Chest ACCP Education Calendar
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Guest Access | Sign In via User Name/Password
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Article Archive
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (10)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lynd, L. D.
Right arrow Articles by Anis, A. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lynd, L. D.
Right arrow Articles by Anis, A. H.
(Chest. 2002;122:1973-1981.)
© 2002 American College of Chest Physicians

Patterns of Inhaled Asthma Medication Use*

A 3-Year Longitudinal Analysis of Prescription Claims Data From British Columbia, Canada

Larry D. Lynd, BSP, PhD; Daphne P. Guh, MSc; Peter D. Paré, MD and Aslam H. Anis, PhD

* From the Department of Health Care and Epidemiology (Drs. Lynd and Anis), University of British Columbia, Vancouver, BC, Canada; and the Centre for Health Evaluation and Outcome (Ms. Guh) and the iCAPTURE Centre (Dr. Paré), Providence Health Care, Vancouver, BC, Canada.

Correspondence to: Aslam H. Anis, PhD, Center for Health Evaluation and Outcome Sciences, 620-1081 Burrard St, Vancouver, BC, Canada V6Z 1Y6; e-mail: anis{at}cheos.ubc.ca


   Abstract
TOP
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Study objectives: To assess trends in asthma management and to identify factors associated with increasing short-acting (SA) ß-agonist utilization in British Columbia using administrative prescription data.

Design: A retrospective cohort analysis.

Setting: All patients between 13 and 50 years of age who had received at least one prescription for a SA ß-agonist covered by BC Pharmacare between January 1, 1996, and December 31, 1998.

Methods: Cross-sectional analysis of all patients, and longitudinal analyses only of patients who had received at least one SA ß-agonist prescription in each of the 3 years. Trends in asthma medication use over time were evaluated using repeated-measures Mantel-Haenszel tests. Multiple logistic regression was used to identify factors associated with increasing SA ß-agonist use.

Results: A total of 78,758 patients were included in the cohort. No decrease in the annual prevalence of receiving more than four canisters per year of a SA ß-agonist was identified between 1996 and 1998. A total of 12,844 patients filled at least one SA ß-agonist prescription each year. Time-trend analysis showed an overall increasing probability of not receiving an inhaled corticosteroid (ICS) agent in this population (p = 0.002). In patients exhibiting low SA ß-agonist use, > 18 years of age (adjusted odds ratio [OR], 1.5), male gender (adjusted OR, 1.7), and in receipt of social assistance (adjusted OR, 2.3) were associated with receiving increasing amounts of SA ß-agonist agents over the 3 years. In patients with a high degree of use of SA ß-agonists, only the receipt of social assistance (adjusted OR, 1.3) was significantly associated with increasing use.

Conclusions: Despite the development and dissemination of asthma management guidelines, there was no trend toward decreasing SA ß-agonist use. An unexpected trend toward decreasing ICS utilization was identified. Receiving social assistance was a risk factor for increasing SA ß-agonist use, independent of baseline utilization.

Key Words: adrenal cortex hormones • adrenergic ß-agonists • asthma • drug therapy • pharmacoepidemiology


   Introduction
TOP
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
Historically, short-acting (SA) inhaled ß-agonists have been the mainstay of asthma management. However, their excessive use has been identified as a potential risk factor for, or marker of, increased asthma-related morbidity and mortality.1 2 3 4 5 6 Although the most recent study7 of chronic SA ß-agonist administration did not find an increase in the asthma exacerbation rate in the population studied, in at least four previous prospective studies8 9 10 11 the regular use of salbutamol and/or fenoterol had detrimental effects on patients in terms of lung function, symptoms, exacerbations, and/or airway responsiveness when compared to their use on an as-needed or rescue basis only.

The increased recognition that airway inflammation plays an integral role in asthma has resulted in a shift from the use of SA ß-agonists to inhaled corticosteroid (ICS) agents as the mainstay of therapy in all but the most mildly affected patients. Current asthma management guidelines12 13 14 define appropriate asthma management as the optimization of ICS doses, with or without add-on therapy (eg, with leukotriene antagonists, long-acting ß-agonists, or chromoglycans), such that no more than three doses per week of a SA ß-agonist are required. Appropriate asthma therapy therefore can be defined as the utilization of two canisters of SA ßagonist per year.

Given the evidence of the risks of excessive SA ß-agonist utilization, either causally or as a marker for deteriorating control or worsening disease, and the recent dissemination of asthma management guidelines, it was our hypothesis that the acceptance and adoption of these guidelines should be reflected in a trend toward more appropriate asthma management in the population. Although the guidelines had been published prior to 1995, it was expected that the effect of this would have deteriorated resulting in a demonstrable improvement in management in the 3 years immediately following their republication. We postulated that this trend should be illustrated by a decrease in the prescription of SA ß-agonist agents and an increase in the utilization of ICS agents, particularly by those patients who are most likely to benefit from their use (ie, asthmatic patients receiving greater than four canisters of SA ß-agonists per year). Using British Columbia (BC) Ministry of Health Pharmacare prescription claims data, we evaluated asthma prescribing practices over a 3-year period following the release and dissemination of the 1995 asthma management guidelines.12 A secondary objective of the analysis was to investigate the factors that are potentially associated with the increasing utilization of SA ß-agonists.


   Materials and Methods
TOP
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Subjects and Sources of Data
Prescription records for all asthma medications were obtained for all patients covered by Pharmacare in BC who had filled at least one prescription for an inhaled SA ß-agonist medication (ie, salbutamol, fenoterol, or terbutaline) in 1996, 1997, or 1998. Pharmacare, the pharmaceutical reimbursement program of the BC government, provides comprehensive first-dollar coverage for all BC residents on social assistance (plan C) and for the general population (plan E) whose annual family pharmaceutical expenditure exceeds their deductible limit ($600 prior to April 1, 1998, and $800 thereafter). Once a family reaches this threshold, each family member becomes eligible for the reimbursement of drug expenditures for those drugs covered by Pharmacare, and their entire drug profile (including drugs prescribed prior to their achievement of the threshold) is added to the database.

Drug Utilization Determination
The annual quantity of inhaled SA ß-agonists received was determined for all patients between 13 and 50 years of age who were on plans C and E and were identified in the Pharmacare database. To control for differences in potency, strength, and formulation, the amount of each specific SA ß-agonist that had been prescribed was standardized to the number of canisters of a salbutamol metered-dose inhaler (MDI) [100 µg per puff and 200 puffs per canister]. Comparative dosages were derived from dosage comparison data and recommended dosages. Salbutamol administered by dry powder inhaler was considered to be half as potent as administration by MDI,14 15 16 and fenoterol and salbutamol were considered equipotent when administered by MDI and nebulizer.17 18 Each dosage form of ICS also was standardized to the equivalent dose of beclomethasone dipropionate (BDP) administered by MDI. BDP was considered to be equipotent to budesonide administered by MDI,19 20 and half as potent when administered by dry powder inhaler.21 22 Triamcinolone14 and fluticasone23 24 25 26 27 were considered to be half and twice as potent, respectively, as BDP when administered by MDI.

All patients were classified ordinally, based on the amount of SA ß-agonists they had received each calendar year, into low users (ie, <= 4 canisters), intermediate users (ie, 5 to 12 canisters), high users (ie, 13 to 20 canisters), or excessive users (ie, > 20 canisters), and they were classified according to their average daily ICS dose for each year (ie, none, 1 to 400 µg/d, 401 to 800 µg/d, and > 800 µg/d). This ordinal classification scheme was developed to reflect increasingly poor asthma control, to provide a gradient of asthma severity, and has been applied in a previous study.28

Study Design
Overall drug utilization patterns were assessed in a cross-sectional analysis of all patients. The longitudinal analyses only of patients who had received at least one SA ß-agonist prescription in each of the 3 years were undertaken to assess transitions between drug use classes. We hypothesized that improved asthma management would be demonstrated by a trend of decreasing SA ß-agonist use and increasing ICS use over the 3 years. Trends in ICS use were evaluated using the following two methods: (1) a trend analysis of the annual prevalence of not receiving a prescription for an ICS; and (2) an analysis of transitions between receiving and not receiving an ICS prescription. In the second analysis, the proportion of subjects who received an ICS prescription in 1996 but not in 1998 was compared with the proportion that did not receive an ICS prescription in 1996 but did so in 1998. Each of these analyses was stratified by the levels of the baseline (ie, 1996) SA ß-agonist use.

Factors associated with increasing SA ß-agonist use were assessed in two discrete samples of this population, as follows: (1) users of low doses of SA ß-agonists (ie, four canisters or fewer) in 1996 who could be considered controlled; and (2) users of more than four canisters in 1996 whose utilization could increase, decrease, or remain static but could be deemed uncontrolled. Controlled subjects who consistently received four or fewer canisters of SA ß-agonist each year were compared with those who were controlled in 1996 but received more than four canisters in 1997 and 1998, and at least four more canisters in 1998 relative to 1996. Because the usage patterns of uncontrolled subjects could change in either direction (as well as remain static), those whose use increased were compared to those whose use decreased. For this analysis, increasing use was defined as the receipt of more SA ß-agonist canisters in both 1997 and 1998 relative to 1996, with an overall increase of at least 50% over the 3 years. Similarly, decreasing use was defined as a consistent decrease of at least 50% in the amount of SA ß-agonist agents received over the 3 years. These cut points were selected based on what was deemed to be indicative of a significant change. A one-way sensitivity analysis around these cut points was performed.

Statistical Analysis
Between-group differences in mean values were compared using the Student t test. To account for correlation within individuals, trends in SA ß-agonist and ICS use over time were evaluated using repeated-measures Mantel-Haenszel tests for dichotomous and ordinal responses.29 30 31 Within-patient transitions between groups were analyzed using the McNemar test.

The relationships between increasing SA ß-agonist utilization and age, gender, Pharmacare plan, and change in mean annualized daily ICS dose were evaluated using multiple logistic regression. The mean daily ICS dose at baseline also was evaluated and was included in the adjusted models if significant. The dependent variable used for the analysis of both subgroups was increasing use, resulting in the determination of odds ratios (ORs) for increasing use relative to remaining in the low-use group over the 3 years in controlled users, and for increasing use relative to decreasing use in uncontrolled users. All variables significant in univariate analyses at a level of {alpha} = 0.10 were included in the multiple regression models. Model fit was assessed using -2 Log likelihood. Crude and adjusted ORs and 95% confidence intervals (CIs) are reported for each variable.


   Results
TOP
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Demographics
A total of 78,758 individual patients in Pharmacare plans C and E filled at least one prescription for a SA ß-agonist in any of the 3 years (1996, 43,277 patients; 1997, 41,790 patients; and 1998, 33,781 patients) [Table 1 ]. A total of 618,519 prescriptions for asthma medications (ie, SA ß-agonists, ICS agents, ipratropium bromide, theophylline, long-acting ß-agonists, chromoglycans, and nedocromil) were filled or refilled over this time period. The majority of the population was composed of women (62.2%; p < 0.001) and were receiving social assistance (ie, Pharmacare plan C; 56%; p < 0.001). The number of patients included in the entire cohort accounts for approximately 17% of the all patients covered by both Pharmacare plans C and E in 1996. The average (± SD) age was 32.3 ± 11.4 years. Patients who were on plan E were significantly older than were patients on plan C (33.3 vs 31.6 years, respectively; p < 0.0001), and women were significantly older than men (32.9 vs 31.5 years, respectively; p < 0.0001).). Of the 10,686 patients who received at least one SA ß-agonist prescription each year, 1,408 (17%) were between 13 and 17 years of age, and 3,463 (32.4%) were between 18 and 35 years of age.


View this table:
[in this window]
[in a new window]

  		Table 1. Annual Number of Canisters of SA ß-Agonist Received*

 
Cross-Sectional Analysis
Although the majority of patients received <= 4 canisters of SA ß-agonist each year, > 2,000 patients (> 6%) received >= 13 canisters, > 40% of whom received > 20 canisters (Table 1) . Among these patients, 1,147 received an average of > 20 canisters per year, of whom 152 (13.2%) averaged > 40 canisters per year. We had hypothesized that, over time, fewer patients would receive inappropriately high doses of SA ß-agonists. However, the proportion of patients in each SA ß-agonist use group varied < 1% between years.

Longitudinal Analysis
A total of 10,686 patients received at least one prescription for an SA ß-agonist each year, 50% of whom consistently received four or fewer canisters per year. A total of 1,141 patients (10.7%) consistently received 5 to 12 canisters per year, and 1,066 (10%) received > 12 canisters in both years, of whom approximately 40% received in excess of 20 canisters per year. A total of 1,589 patients (14.9%) transitioned upward between usage groups between 1996 and 1998, vs 1,804 patients (16.8%) who transitioned downward. A trend analysis did not provide any meaningful indication of either increasing or decreasing SA ß-agonist use over the 3 years.

Each year, approximately 40% of the patients in this population did not fill a prescription for an ICS. Even though the majority of these patients received <= 4 canisters per year of SA ß-agonists, and thus are patients for whom an ICS would not necessarily be indicated, more than one third of ICS nonusers consistently received > 12 canisters per year of an SA ß-agonist agent. A trend analysis did not reveal any evidence of increasing ICS use over the 3 years. To the contrary, Figure 1 illustrates a trend toward an increasing prevalence of not receiving any ICS (p < 0.0001) among subjects who received at least one SA ß-agonist prescription each year. Because this finding could be related to decreasing asthma severity, we repeated the analysis in the 966 patients who received at least 13 canisters in all 3 years and found that their probability of not receiving an ICS increased from 0.16 to 0.20 (p = 0.002) between 1996 and 1998.



View larger version (49K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 1. Trends in the annual prevalence of not receiving a prescription for an ICS among SA ß-agonist users. ** = p <= 0.0001 (by Mantel-Haenszel test for trends).

 
Figure 2 illustrates the comparison of the proportion of patients who filled at least one prescription for an ICS in 1996 but did not do so in 1998 to the proportion that did not fill an ICS prescription in 1996 but did so in 1998. Although there was no difference in proportions in the low-use group, significantly more patients appear to have discontinued ICS therapy than were initiated on it over the 3 years. The most salient discrepancy occurred in the excessive SA ß-agonist users, 16.4% of whom received a prescription for an ICS in 1996 but did not do so in 1998 compared to only 4.7% who initiated ICS therapy (p < 0.0001).



View larger version (58K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 2. Transitions between receiving and not receiving at least one ICS prescription (by 1996 ß-agonist use group). ** = p < 0.0001 (by McNemar test).

 
Factors Association With Increasing SA ß-Agonist Use
The analysis of factors associated with increasing SA ß-agonist use in previously controlled patients is presented in Table 2 . A total of 6,449 patients received four or fewer canisters of an SA ß-agonist in 1996. A total of 4,932 patients remained in this use group in all 3 years vs 631 who consistently increased their use over the 3 years and received at least four more canisters in 1998 relative to 1996 (median increase, 6.0; interquartile range, 4.6 to 9.0).


View this table:
[in this window]
[in a new window]

  		Table 2. Factors Associated With Increasing SA ß-Agonist Use Among Controlled Users in 1996 (n = 5,563)*

 
Logistic regression analysis revealed a positive association between increasing SA ß-agonist use and all the factors tested. In the fully adjusted model, individuals between 18 and 34 years of age were 1.5 times more likely than those < 18 years of age to increase their ß-agonist use, and being a man or receiving social assistance increased the risk of increasing SA ß-agonist use by 1.7 and 2.3 times, respectively. A positive association between increasing SA ß-agonist use and both average daily ICS dose in 1996 and the change in ICS dose between 1996 and 1998 also was found.

Of 4,237 patients who received more than four canisters of an SA ß-agonist in 1996, 584 and 1,332, respectively, met the criteria of increasing and decreasing use (Table 3 ). Patients whose use decreased received significantly more canisters of SA ß-agonists (13.0 vs 9.3, respectively; p < 0.0001) and had a higher mean daily ICS dose (475 vs 326 µg/d, respectively; p < 0.0001) at baseline than those whose use increased. More plan C patients than plan E patients also increased their use over the 3 years (33.0% vs 25.2%, respectively; p = 0.004). Although there was no relationship between age and increasing use in uncontrolled patients, and the association between gender and increasing use was attenuated in the adjusted model, the receipt of social assistance remained significant. Patients on Pharmacare plan C were 1.3 times more likely than patients on plan E to increase their SA ß-agonist use by at least 50%. Sensitivity analysis, varying increasing use from two to six canisters per year in controlled users, and varying increasing and decreasing use from 30 to 70% in uncontrolled users, resulted in consistent findings.


View this table:
[in this window]
[in a new window]

  		Table 3. Factors Associated With Increasing SA ß-Agonist Use Among Uncontrolled Users in 1996 (n = 1,916)*

 

   Discussion
TOP
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
Current asthma management guidelines stipulate that a primary goal of asthma management should be the minimization of SA ß-agonist use to no more than three doses per week by increasing the use of ICS and other add-on agents. Realizing that the goal of asthma management should be to improve overall asthma control rather than merely to decrease the amount of SA ß-agonist use, and given the absence of other measures of control, we have used SA ß-agonist use as a surrogate measure of asthma control.

Each year, approximately 5% of this population received > 12 canisters of SA ß-agonist, more than half of whom were prescribed > 20 canisters, far exceeding the desired management goal. Although the total number of clients decreased from 1997 to 1998, there was no change in the distribution of the users. This decrease may have been at least partially attributable to the increase in the deductible that became effective April 1, 1998. The prevalence of SA ß-agonist use in this sample was greater than the prevalence of asthma in the general population (17% vs 5 to 10%, respectively). This was not unexpected given the apparent higher prevalence of asthma in lower social classes32 33

In a previous Canadian study, Habbick et al34 demonstrated an increase in the annual prevalence of ICS use between 1989 and 1992, with a subsequent decrease in 1993. This reversal may have occurred due to the weakening of the effect of the 1990 publication of the guidelines. Although we expected to identify some effect following the republication of the guidelines, we were unable to identify any trends toward improved asthma management in terms of either decreasing SA ß-agonist use or increasing ICS use. In this population, it appears that inappropriate management persists and may be deteriorating further. Even though this is only a sample of the population of asthmatic patients in BC and provides a conservative estimate of the overall magnitude of inappropriate overutilization of SA ß- agonists, it provides ample evidence of persistent inappropriate overreliance on SA bronchodilators.

The benefits of adding ICS to SA ß-agonist therapy are well-established, with the most marked benefits occurring in those patients using the highest doses of SA ß-agonist agents.28 35 36 37 Although our finding that patients whose SA ß-agonist use decreased were receiving greater amounts at baseline can be attributed at least partially to regression to the mean, the finding of higher average annual daily doses of ICS agents at baseline in uncontrolled patients whose SA ß-agonist use decreased cannot. This is not an unexpected finding and may further illustrate the beneficial effects of ICS therapy. Despite this, each year approximately 500 patients who received > 12 canisters of SA ß-agonist did not receive any concomitant therapy with an ICS. Furthermore, we identified a paradoxical trend of decreasing ICS use, which is illustrated by an increasing prevalence of not receiving an ICS and a greater likelihood of not receiving an ICS after having received one previously than of starting to receive one. Most disconcertingly, these trends were most pronounced in patients who are the most likely to benefit from concomitant ICS therapy (ie, the excessive SA ß-agonist users).

A subgroup analysis of factors associated with increasing use identified increasing ICS dose as the strongest risk factor for increasing SA ß-agonist use, which likely is indicative of increasing asthma severity. These analyses therefore demonstrate different associations of age, gender, and receipt of social assistance with increasing SA ß-agonist use in controlled and uncontrolled patients, independent of disease severity.

One of the most noteworthy associations identified was the greater risk of increasing SA ß-agonist use by subjects on social assistance. However, because this sample is composed only of patients who exceeded their family deductible or who received social assistance benefits, a sample selection bias is potentially manifest. Patients receiving benefits under Pharmacare plan E may represent those persons in the general population with the most severe or most poorly controlled asthma. If so, this analysis will provide a conservatively biased estimate of the true risk of increasing SA ß-agonist use by plan C patients relative to the general population. Although previous studies38 39 have attributed class differences in asthma-related outcomes to disease severity, this study indicates that poorer asthma control also may be contributory.

Previous studies40 41 have shown increases in the annual prevalence of ICS use but have utilized annual cross-sectional analysis only and may, therefore, be confounded by asthma prevalence. By utilizing a repeated-measures analysis and including only subjects in the data set each year, we controlled for this potential confounding and were able to more accurately assess drug utilization patterns, independent of asthma prevalence. Despite this, a limitation of this analysis is that this is not an incident cohort and, in fact, is likely composed of mostly prevalent SA ß-agonist users. Patients receiving long-term therapy may be less likely to alter their therapy or to have it changed, whereas newly treated asthmatic patients may be more apt to be treated in accordance with the guidelines. It was not possible to test this hypothesis using these data.

The majority of patients in this sample received four or fewer canisters of SA ß-agonists and may therefore not be asthmatic. To determine the frequency of the prescribing of SA ß-agonist medications for indications other than asthma in this population, we utilized data from IMSHealth Canada (Mississauga, ON, Canada [an independent pharmaceutical research firm]) and estimated that approximately 85% of prescriptions for SA ß-agonists in this age group are prescribed for the treatment of asthma. Most nonasthmatic patients likely received a SA ß-agonist for an acute indication and will therefore be classified as low users, resulting in a conservatively biased estimate of the proportion of asthmatic patients using inappropriately high amounts of SA ß-agonists. This bias is less likely to affect the longitudinal analysis given the inclusion only of patients who had received an SA ß-agonist prescription each year.

At least two previous studies28 42 also have identified potential asthmatic patients based on the receipt of at least one canister of an SA ß-agonist in a year. Theoretically, because one goal of asthma management is to minimize the use of SA ß-agonists to less than four doses (eight puffs) per week or approximately two canisters per year, this has the potential to exclude the most well-controlled asthmatic patients. In a study by Diette et al,43 SA ß-agonists were the most frequently prescribed medication, with 94.4% of patients with moderate-to-severe asthma reporting their use. Gaist et al40 evaluated asthma medication utilization patterns in persons 20 to 44 years old between 1991 and 1994 and found that in 1994 only 4.3% of asthmatic patients receiving moderate to high doses of ICS agents used the equivalent of less than four canisters of an SA ß-agonist medication. It is likely that < 1% of these patients used less than one canister. Thus, although it is a theoretical consideration, the magnitude of this potential bias is minimal and is unlikely to affect our findings significantly.

Because these results are based entirely on computerized prescription drug data of dispensed medications, they may not coincide precisely with the actual intake of the medications, potentially resulting in some misclassification of drug use. It is also possible that some patients may acquire extra canisters of an SA ß-agonist for security reasons. Although this is a limitation of using administrative prescription data for any pharmacoepidemiologic study, the abundance of previous studies2 3 6 28 44 45 46 47 48 49 specifically investigating asthma using this methodology suggests that it is an acceptable limitation. Using annualized prescription data and assuming that the receipt of a prescription approximates usage patterns eliminates the potential recall bias and attenuates any effect of the seasonal variation in drug utilization. The large sample size and longitudinal analysis in this study should minimize the impact of this potential prescription bias.

This analysis demonstrates a continued overreliance on as-needed inhaled ß-agonist medications, which is one measure of asthma control. Even though this is only a sample of the population, it provides disconcerting evidence of the potential magnitude of the problem. Although we have identified age, gender, and social class as potential contributing factors, other etiologic factors contributing to this inappropriate utilization remain to be elucidated. A recent survey of Canadian asthmatic patients suggested other potential causes such as inappropriate prescribing, lack of specialist referral, inappropriate asthma medication utilization, inaccurate patient and physician perceptions of asthma severity and control, and erroneous understanding of the role of ß-agonist and ICS medications in asthma management.50 The explication of the physiologic, social, behavioral, and control factors contributing to persistent excessive SA ß-agonist utilization will facilitate the identification of patients who are prone to a lack of control and the targeting of management resources to asthmatic patients who are the most likely to benefit from those resources.


   Footnotes
 
Abbreviations: BC = British Columbia; BDP = beclomethasone dipropionate; CI = confidence interval; ICS = inhaled corticosteroid; MDI = metered-dose inhaler; OR = odds ratio; SA = short-acting

This work was supported by a grant from the British Columbia Lung Association, and was part of Dr. Lynd’s doctoral dissertation. Dr. Lynd was supported by a Canadian Institutes for Health

Research doctoral fellowship. Dr. Anis’ research program was supported by a grant from the BC Ministry of Health, and the Ministry responsible for Seniors.

Received for publication August 23, 2001. Accepted for publication June 27, 2002.


   References
TOP
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Speizer, F, Doll, R, Heaf, P (1968) Observations on recent increases in mortality from asthma. BMJ 1,335-339[ISI][Medline]
  2. Grainger, J, Woodman, K, Pearce, N, et al Prescribed fenoterol and death from asthma in New Zealand 1981–1987: a further case-control study. Thorax 1991;46,105-111[Abstract]
  3. Spitzer, W, Suissa, S, Ernst, P, et al The use of beta-agonists and the risk of death and near death from asthma. N Engl J Med 1992;326,501-506[Abstract]
  4. Ernst, P, Habbick, B, Suissa, S, et al Is the association between inhaled beta-agonist use and life-threatening asthma because of confounding by severity? Am Rev Respir Dis 1993;148,75-79[ISI][Medline]
  5. Suissa, S, Ernst, P, Boivin, J-F, et al A cohort analysis of excess mortality in asthma and the use of inhaled beta-agonists. Am J Respir Crit Care Med 1994;149,604-610[Abstract]
  6. Suissa, S, Blais, L, Ernst, P Patterns of increasing beta-agonist use and the risk of fatal or near-fatal asthma. Eur Respir J 1994;7,1602-1609[Abstract]
  7. Dennis, SM, Sharp, SJ, Vickers, MR, et al Regular inhaled salbutamol and asthma control: the TRUST randomised trial; Therapy Working Group of the National Asthma Task Force and the MRC General Practice Research Framework. Lancet 2000;355,1675-1679[CrossRef][ISI][Medline]
  8. Sears, MR, Taylor, DR, Print, CG, et al Regular inhaled beta-agonist treatment in bronchial asthma. Lancet 1990;336,1391-1396[CrossRef][ISI][Medline]
  9. Van Ganse, E, van der Linden, PD, Leufkens, HG, et al Asthma medications and disease exacerbations: an epidemiological study as a method for asthma surveillance. Eur Respir J 1995;8,1856-1860[Abstract]
  10. Taylor, D, Sears, M, Herbison, G, et al Regular inhaled beta-agonist in asthma: effects on exacerbations and lung function. Thorax 1993;48,134-138[Abstract]
  11. van Schayck, CP, Dompeling, E, van Herwaarden Cees, L, et al Bronchodilator treatment in moderate asthma or chronic bronchitis: continuous or on demand? A randomized controlled study. BMJ 1991;303,1426-1430[ISI][Medline]
  12. Ernst, P, Fitzgerald, J, Spier, S Canadian asthma consensus conference summary of recommendations. Can Respir J 1996;3,89-100
  13. Boulet, L-P, Becker, A, Bérubé, D, et al Canadian asthma consensus report, 1999. Can Med Assoc J 1999;161(suppl),S1-S62[Free Full Text]
  14. National Asthma Education and Prevention Program. Expert panel report 2: guidelines for the diagnosis and management of asthma. April 1997 National Institute of Health Bethesda, MD. Publication No. 97–4051
  15. Hebel, S eds. Drug facts and comparisons 2000 Facts and Comparisons St. Louis, MO.
  16. Young, LY, Koda-Kimble, MA Applied therapeutics: the clinical use of drugs 6th ed. 1995 Applied Therapeutics Vancouver, WA.
  17. Newhouse, MT, Dolovich, MB, Kazim, F Dose-effect relationship of the beta-agonists fenoterol and salbutamol in patients with asthma. Chest 1994;105,1738-1742[Abstract/Free Full Text]
  18. Lipworth, BJ, Newnham, DM, Clark, RA, et al Comparison of the relative airways and systemic potencies of inhaled fenoterol and salbutamol in asthmatic patients. Thorax 1995;50,54-61[Abstract]
  19. Bjorkander, J, Formgren, H, Johansson, SA, et al Methodological aspects on clinical trials with inhaled corticosteroids: results of two comparisons between two steroid aerosols in patients with asthma. Eur J Respir Dis Suppl 1982;122,108-117[Medline]
  20. Ebden, P, Jenkins, A, Houston, G, et al Comparison of two high dose corticosteroid aerosol treatments, beclomethasone dipropionate (1500 micrograms/day) and budesonide (1600 micrograms/day), for chronic asthma. Thorax 1986;41,869-874[Abstract]
  21. Thorsson, L, Edsbacker, S, Conradson, TB Lung deposition of budesonide from Turbuhaler is twice that from a pressurized metered-dose inhaler P-MDI. Eur Respir J 1994;7,1839-1844[Abstract]
  22. Agertoft, L, Pedersen, S Importance of the inhalation device on the effect of budesonide. Arch Dis Child 1993;69,130-133[Abstract]
  23. Gustafsson, P, Tsanakas, J, Gold, M, et al Comparison of the efficacy and safety of inhaled fluticasone propionate 200 micrograms/day with inhaled beclomethasone dipropionate 400 micrograms/day in mild and moderate asthma. Arch Dis Child 1993;69,206-211[Abstract]
  24. Ayres, JG, Bateman, ED, Lundback, B, et al High dose fluticasone propionate, 1 mg daily, vs fluticasone propionate, 2 mg daily, or budesonide, 1.6 mg daily, in patients with chronic severe asthma: International Study Group. Eur Respir J 1995;8,579-586[Abstract]
  25. Fabbri, L, Burge, PS, Croonenborgh, L, et al Comparison of fluticasone propionate with beclomethasone dipropionate in moderate to severe asthma treated for one year: International Study Group. Thorax 1993;48,817-823[Abstract]
  26. Dahl, R, Lundback, B, Malo, JL, et al A dose-ranging study of fluticasone propionate in adult patients with moderate asthma: International Study Group. Chest 1993;104,1352-1358[Abstract/Free Full Text]
  27. Barnes, NC, Marone, G, Di Maria, GU, et al A comparison of fluticasone propionate, 1 mg daily, with beclomethasone dipropionate, 2 mg daily, in the treatment of severe asthma: International Study Group. Eur Respir J 1993;6,877-885[Abstract]
  28. Anis, A, Lynd, L, Wang, X, et al Double trouble: inappropriate asthma medication use linked to increased use of health care resources. Can Med Assoc J 2001;164,625-631[Abstract/Free Full Text]
  29. Stokes, M, Davies, C, Koch, G Categorical data analysis using the SAS system. 1995 SAS Institute Cary, NC.
  30. Landis, J, Heyman, E, Koch, G Average partial association in three-way contingency tables: a review and discussion of alternative tests. Int Stat Rev 1978;46,237-254
  31. Kuritz, S, Landis, J, Koch, G A general overview of Mantel-Haenszel methods: applications and recent developments. Annu Rev Public Health 1988;84,1813-1817
  32. Persky, VW, Slezak, J, Contreras, A, et al Relationships of race and socioeconomic status with prevalence, severity, and symptoms of asthma in Chicago school children. Ann Allergy Asthma Immunol 1998;81,266-271[ISI][Medline]
  33. Litonjua, AA, Carey, VJ, Weiss, ST, et al Race, socioeconomic factors, and area of residence are associated with asthma prevalence. Pediatr Pulmonol 1999;28,394-401[CrossRef][ISI][Medline]
  34. Habbick, B, Baker, MJ, McNutt, M, et al Recent trends in the use of inhaled beta 2-adrenergic agonists and inhaled corticosteroids in Saskatchewan. CMAJ 1995;153,1437-1443[Abstract]
  35. Donahue, JG, Weiss, ST, Livingston, JM, et al Inhaled steroids and the risk of hospitalization for asthma. JAMA 1997;277,887-891[Abstract]
  36. Wennergren, G, Kristjansson, S, Strannegard, IL Decrease in hospitalization for treatment of childhood asthma with increased use of antiinflammatory treatment, despite an increase in prevalence of asthma. J Allergy Clin Immunol 1996;97,742-748[CrossRef][ISI][Medline]
  37. Gottlieb, DJ, Beiser, AS, O’Connor, GT Poverty, race, and medication use are correlates of asthma hospitalization rates: a small area analysis in Boston. Chest 1995;108,28-35[Abstract/Free Full Text]
  38. Erzen, D, Carriere, K, Dik, N, et al Income level and asthma prevalence and care patterns. Am J Respir Crit Care Med 1997;155,1060-1065[Abstract]
  39. Littlejohns, P, Macdonald, LD The relationship between severe asthma and social class. Respir Med 1993;87,139-143[CrossRef][ISI][Medline]
  40. Gaist, D, Hallas, J, Hansen, NC, et al Are young adults with asthma treated sufficiently with inhaled steroids? A population-based study of prescription data from 1991 and 1994. Br J Clin Pharmacol 1996;41,285-289[CrossRef][ISI][Medline]
  41. Goodman, DC, Lozano, P, Stukel, TA, et al Has asthma medication use in children become more frequent, more appropriate, or both? Pediatrics 1999;104,187-194[Abstract/Free Full Text]
  42. Blais, R, Gregoire, JP, Rouleau, R, et al Ambulatory use of inhaled beta(2)-agonists for the treatment of asthma in Quebec: a population-based utilization review. Chest 2001;119,1316-1321[Abstract/Free Full Text]
  43. Diette, GB, Wu, AW, Skinner, EA, et al Treatment patterns among adult patients with asthma: factors associated with overuse of inhaled beta-agonists and underuse of inhaled corticosteroids. Arch Intern Med 1999;159,2697-2704[Abstract/Free Full Text]
  44. Sears, MR, Rea, HH, Beaglehole, R Asthma mortality: a review of recent experience in New Zealand. J Allergy Clin Immunol 1987;80,319-325[CrossRef][ISI][Medline]
  45. Beasley, R, Pearce, N, Crane, J, et al Asthma mortality and inhaled beta-agonist therapy. Aust N Z J Med 1991;21,753-763[ISI][Medline]
  46. Crane, J, Pearce, N, Flatt, A Prescribed fenoterol and death from asthma in New Zealand, 1981–1983: a case-control study. Lancet 1989;1,917-922[ISI][Medline]
  47. Blais, L, Ernst, P, Suissa, S Confounding by indication and channeling over time: the risk of beta-2 agonists. Am J Epidemiol 1996;144,1161-1169[Abstract/Free Full Text]
  48. Suissa, S, Ernst, P, Benayoun, S, et al Low-dose inhaled corticosteroids and the prevention of death from asthma. N Engl J Med 2000;343,332-336[Abstract/Free Full Text]
  49. Blais, L, Suissa, S, Boivin, JF, et al First treatment with inhaled corticosteroids and the prevention of admissions to hospital for asthma. Thorax 1998;53,1025-1029[Abstract/Free Full Text]
  50. Glaxo Wellcome.. Asthma in Canada: a landmark survey 2000 Glaxo Wellcome Mississauga, ON, Canada.



This article has been cited by other articles:


Home page
 ChestHome page
L. D. Lynd, A. J. Sandford, E. M. Kelly, P. D. Pare, T. R. Bai, J. M. FitzGerald, and A. H. Anis
Reconcilable Differences: A Cross-sectional Study of the Relationship Between Socioeconomic Status and the Magnitude of Short-Acting {beta}-Agonist Use in Asthma
Chest, October 1, 2004; 126(4): 1161 - 1168.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Article Archive
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (10)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lynd, L. D.
Right arrow Articles by Anis, A. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lynd, L. D.
Right arrow Articles by Anis, A. H.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS