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* From the Departments of Anesthesiology (Drs. Dirard, Chouinard, and Boudreault, and Ms. Ruel), Medicine (Dr. Poirier and Ms. Richard), and Surgery (Dr. Ferraro), CHUM Hôpital Notre-Dame, Montreal, Canada.
Correspondence to: François Girard, MD, Department of Anesthesiology, CHUM Hopital Notre-Dame, 1560 Sherbrooke East, Montreal, Canada, H2L 4M1; e-mail: francois.girard.chum{at}ssss.gouv.qc.ca
Abstract
Study objective: To study the prevalence and impact of pain on the quality of life (QOL) of lung transplant recipients.
Design and patients: Prospective, observational, cross-sectional study. Ninety-six lung transplant recipients (> 3 months after transplantation) completed questionnaires measuring the severity and impact of pain (Brief Pain Inventory), anxiety (State Trait Anxiety Inventory), QOL (Short Form-36 version 2 [SF-36v2]), and depression (Beck Depression Inventory [BDI]).
Setting: University medical center lung transplant outpatient clinic.
Results: The prevalence of pain in lung transplant recipients was 49%. Patients with pain were older, more likely to have undergone unilateral lung transplantation (64% vs 40%, p = 0.03), and were more likely to have lung emphysema (55% vs 38%, p = 0.004). Only a pulmonary diagnosis of lung emphysema remained an independent predictor for postoperative pain in a logistic regression model. Average (± SD) score of the BDI was 9.6 ± 7.8 and 5.8 ± 5.8 (p = 0.005) for patients with and without pain, respectively. Patients with and without pain did not significantly differ in terms of anxiety. Pain-free patients had a significantly higher physical component score than patients with pain in the SF-36v2 (mean, 48.7 ± 8.6 vs 38.6 ± 9.8, p < 0.0001, respectively), while the mental component scores were not statistically different between the two groups.
Conclusions: Lung transplant recipients have a high prevalence of pain. Patients with lung emphysema as their preoperative diagnosis are more likely to have pain. The occurrence of pain is associated with a decreased QOL in lung transplant recipients.
Key Words: Lung transplantation • lung recipients • chronic pain • pain • anxiety • depression • quality of life.
Several studies12345678910111213 have demonstrated that lung transplantation can improve quality of life (QOL). Existing studies have focused on the influence on QOL of persisting respiratory problems,6 side effects from immunosuppression,6 and level of anxiety and depression.1
Chronic pain is known to significantly affect QOL.14 This issue has not been adequately evaluated in lung transplant recipients. The few studies571113 that have addressed the presence of pain in this patient population have done so using general questionnaires that do not provide reliable data on its prevalence and impact in lung transplant recipients.
The Brief Pain Inventory (BPI) is a short questionnaire designed to assess the severity and impact of pain. Initially designed for the assessment of pain in cancer patients, the BPI has also been used to evaluate patients with noncancer pain.15 To our knowledge, it has never been administered to a lung transplant recipient population.
In this study, we investigated patients who underwent lung transplantation > 3 months previously. In a prospective observational and cross-sectional design, the level of anxiety, QOL, and the presence of depression were assessed with a detailed evaluation of the presence and quality of pain. We looked at risk factors for the presence of pain as well as its impact on the precited indexes of patient well-being. Our hypothesis, based on our previous study16 showing a high incidence of poorly controlled acute postoperative pain, was that lung transplant recipients have a high incidence of pain > 3 months after the surgery and that this would have a significant impact on their QOL.
Materials and Methods
Sample
The study population consisted of all patients who had undergone lung transplantation between 1989 and 2002 (> 3 months before the assessment) and were regularly followed up at the University of Montreal Medical Center lung transplant outpatient clinic. Heart and lung transplant recipients were not included in the study. Following institutional review board approval and written informed consent, the questionnaires used for the study were administered to the patients during a postoperative follow-up visit, and all explanations regarding the questionnaires were provided at that time.
Instruments
The BPI was developed to provide information on the intensity of pain as well as the degree to which pain interferes with function. The BPI contains 25 questions concerning pain relief, pain quality, and the patient’s perception of the cause of pain.
The Medical Outcome Survey Short Form-36 version 2 (SF-36v2) is a widely used general measure of health. The SF-36v2 assess the ability to perform physical activity; the ability to perform in one’s major social role (work for example), as influenced by physical health; overall general health; vitality; the ability to function socially; emotional health; and mental health. Results are usually presented as summary measures: the physical health component score (PCS) is the summation of the first four indexes (bodily pain through overall general health), whereas the mental health component score (MCS) regroups the last four indexes (from vitality to mental health). The summaries and eight domain scales are adjusted with scores ranging from 0 (worst) to 100 (best). Scoring is standardized according to the 1998 US general population.
The Spielberger State Trait Anxiety Inventory (STAI) is a self-report assessment device that includes two 20-item inventories that measure state and trait anxiety. The STAI differentiates between the temporary condition of state anxiety and the more general and long-standing quality of trait anxiety. For each inventory, scores range from 20 to 80.
The Beck Depression Inventory (BDI) is a 21-item self-report test that purports to measure presence and degree of depression. Beck recommended the following cutoff scores: 0 to 9, asymptomatic for depression; 10 to 18, mild-to-moderate depression; 19 to 29, moderate-to-severe depression; and 30 to 63, extremely severe depression.
The presence of pain was established by a positive response to question 10 of the BPI: Have you had pain other than everyday kinds of pain (a minor headache, sprains, toothaches) during the last week? Only patients who indicated that the pain was secondary to the effects of treatment and/or their primary disease in question 21 of the BPI were kept for analysis.
Data were stored in a database (Excel; Microsoft; Redmond, WA), and statistical analysis was performed using a statistical software package (SPSS, version 9.0; SPSS; Chicago, IL). Differences between the groups were sought using two-tailed 
2 and unpaired Student t tests for dichotomous and parametrical variables, respectively. Multivariate stepwise logistic regression analysis was used to search for predictive factors of pain; p < 0.05 was considered significant.
Results
Of the 99 eligible patients, 96 agreed to participate in the study (97% response rate): 47 men (49%) and 49 women (51%) [median age, 45 years; range, 16 to 66 years]. Demographic data are presented in Table 1 . Fifty-six of 96 patients reported pain in the BPI. However, the pain was related to the treatment and/or surgery in 47 of them, for a prevalence of 49%. The location of pain is shown in Table 2 . Thirty-two of 47 patients reported pain along the surgical scar. The second most important site of pain was the back (28 patients). Patients reporting pain were older, more likely to have undergone unilateral lung transplantation (64% vs 40%; odds ratio [OR], 2.7; 95% confidence interval [CI], 1.1 to 6.8; p = 0.03) and have lung emphysema (55% vs 38%; OR, 4.7; 95 CI, 1.6 to 14.6; p = 0.004) as their preoperative pulmonary diagnosis. When these data were entered into a logistic regression model, only the pulmonary diagnosis (lung emphysema) remained as an independent predictor for postoperative pain. Notably, the use of an epidural catheter as the first postoperative pain treatment modality (OR, 2.5; 95 CI, 0.7 to 10.5; p = 0.2) and patient gender (OR, 2.2; 95 CI, 0.9 to 5.6; p = 0.1) did not have an influence on the presence of pain.
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In this cross-sectional descriptive study, we evaluated the prevalence and impact on QOL of pain in lung transplant recipients. We showed that 49% of lung transplant recipients have pain at different locations. The prevalence of postthoracotomy syndrome per se (pain along the thoracotomy scar) was 33% in this study. This is consistent with the prevalence of chronic pain following thoracotomy for other indications, which is reported to be from 12 to 67% > 2 months following surgery.171819202122
A few studies have succinctly investigated the impact of postthoracotomy pain on daily life activities, and results are somewhat conflicting. In the study by Katz et al,17 52% of the 30 postthoracotomy patients studied still had pain on a daily or weekly basis 2 years after the surgery. The presence of pain did not, however, affect the BDI and both STAI scores. Perttunen and colleagues20 found a prevalence of chronic pain of 61% 1 year after surgery with a 3 to 5% incidence of severe pain in 67 postthoracotomy patients. In this study, the presence of pain interfered with the patient’s normal daily life in more than half of the cases.
In the present study, 58% of patients reporting pain had moderate-to-severe pain (score > 3 on a scale of 10) on average, and 72% of patients were taking analgesics on a daily or weekly basis. This suggests that a significant proportion of these patients might have a chronic pain syndrome.
Our results indicate that QOL was significantly affected in patients who reported pain in the BPI. Areas where pain interfered the most with daily activities were sleep, normal work, and walking ability in percentages ranging from 40 to 55% for moderate-to-severe interference. General activity and mood were also affected. Relationship with other people, enjoyment of life, appetite, and concentration were the least affected (23 to 32% for moderate-to-severe interference). In addition, patients with pain scored higher on the BDI, indicating a greater tendency to present symptoms of depression. In our study, patients reporting pain had an average (± SD) BDI score of 9.6 ± 7.8, whereas pain-free patients had a BDI score of 5.8 ± 5.8. It therefore appears that the presence of pain has a significant impact on the prevalence of depressive symptoms in lung transplant recipients. BDI scores reported in the literature for the same patient population are very similar to those obtained in our group of patients with pain. Effectively, Burker et al23 obtained a BDI score of 9.56 ± 7.24 for patients awaiting lung transplantation, whereas Cohen and collaborators3 obtained 9.82 ± 5.92 in 85 lung transplant recipients who were not dichotomized into chronic pain and nonchronic pain categories.
In addition, our results show that patients with pain following lung transplantation had lower PCSs on the SF-36v2 as compared to pain-free patients. The latter scored approximately the same on the PCS and the MCS. Since higher scores indicate a better QOL, this indicates that patients reporting pain after lung transplantation are subject to physical limitation when compared to the healthy population,25 and it does not appear to be the case for pain-free patients. Patients in both groups did not have any restriction in their vitality and mental health when compared to healthy subjects.24
The results we obtained for lung recipients reporting pain are in agreement with other studies56 that have administered the SF-36 to post-lung transplant patients. These studies all show a PCS significantly lower than the MCS. What is interesting in our study is that pain-free patients did not have a lower PCS, suggesting that the presence of postoperative pain is associated with a reduced QOL after lung transplantation.
Our two groups of patients had similar scores for both components of the STAI. The results obtained were somewhat higher than those found in the literature323 for the same patient population. Cohen et al3 obtained STAI state scores of 36.16 ± 10.28 and trait scores of 35.77 ± 9.76 in lung transplant recipients, whereas Burker et al23 obtained STAI trait scores of 36.5 ± 9.48 and state scores of 37.1 ± 11.6 in lung transplant candidates.
In our study, the only independent predictor for the presence of pain following lung transplantation was a preoperative pulmonary diagnosis of lung emphysema. Why patients with emphysema are overrepresented in the group of patients reporting pain in comparison to patients with cystic fibrosis is not clear. There are some differences between these two groups of patients. Firstly, emphysema patients (52.3 ± 7.5) are twice as old as cystic fibrosis patients (26.2 ± 7.1, p < 0.01). In one study,25 postthoracotomy residual pain persisted longer in patients aged 
50 years old. Secondly, the surgical approach is different. All emphysema patients underwent unilateral lung transplantation through a posterolateral thoracotomy, as opposed to cystic fibrosis patients who underwent bilateral lung transplantation through an anterior thoracosternotomy (clamshell incision). There was a major difference between these two groups in terms of localization of pain. Fifteen of 17 patients (88%) with bilateral lung transplantation had pain along the thoracotomy scar for 57% in unilateral lung transplant recipients (p = 0.006). A difference in the pathophysiology of pain between these two groups appears evident. A study evaluating the presence of preoperative chronic pain in lung transplant candidates might give a better insight to answer this question.
Limitations
The BPI is not a tool that specifically assesses the presence of chronic pain. Patients who indicated the presence of pain on the BPI are therefore not necessarily suffering from chronic pain. This might account for the high prevalence of pain (49%) reported in the present study. However, certain factors suggest that the pain reported in the BPI questionnaire may in fact be chronic in the majority of cases: pain location (most patients reported pain along the surgical scar and in the back), and the high percentage of patients taking analgesics and/or opioid medications.
The presence of preoperative chronic pain is a strong predictive factor for postoperative chronic pain. In our study, we could not reliably identify which patients had preoperative pain because the question assessing this problem in the BPI had a biased formulation: "when you first received your diagnosis, was pain one of your symptoms ?" (question 8, BPI). Cystic fibrosis patients, for example, "learned" their diagnosis at a very early age. It is thus difficult to establish how many cystic fibrosis patients really had preoperative pain and yet answered "no" to this specific question. We thereby chose not to include positive answers to this question in the logistic regression model.
Furthermore, the cross-sectional design of this study implies that we did not investigate patients preoperatively. This would have provided useful information to infer about risk factors for chronic postoperative pain. Finally, results from this single-center study might not be generalized to other centers, since the population of patients and the surgical and anesthesia techniques may differ.
Conclusion
In the present study, we showed that pain is prevalent in the lung transplant population and that it has a significant impact on QOL. A preoperative diagnosis of lung emphysema is associated with an increased likelihood of presenting post-lung transplant pain. A longitudinal cohort study would provide better insight in defining risk factors associated with the presence of pain following lung transplantation.
Footnotes
Abbreviations: BDI = Beck Depression Inventory; BPI = Brief Pain Inventory; CI = confidence interval; MCS = mental health component score; OR = odds ratio; PCS = physical health component score; QOL = quality of life; SF-36v2 = Medical Outcome Survey Short Form-36 version 2; STAI = Spielberger State Trait Anxiety Inventory
The authors of this article have no conflicts of interest to disclose.
Received for publication March 13, 2006. Accepted for publication May 17, 2006.
References
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