Effects of Coronary Angioplasty, Coronary Bypass Surgery, and Medical Therapy on Employment in Patients with Coronary Artery Disease: A Prospective Comparison Study

Coronary bypass surgery and coronary angioplasty have been shown in randomized clinical trials to relieve angina and to improve exercise tolerance when compared with medical therapy [1-3]. Although survival is improved for selected subsets of higher-risk patients with coronary artery disease who are treated with bypass surgery [4], many patients treated with angioplasty are low risk, and the survival benefits of angioplasty remain inconclusive. The economic cost of coronary revascularization is relatively high, but these costs could be mitigated in part by improved patient function and particularly by improved rates of return to work. Previous randomized trials and observational treatment comparisons [1, 2, 5, 6] have failed to show an effect of bypass surgery on return-to-work rates, contrary to initial expectations. Most of these studies were done during the 1970s; however, substantial evidence exists that bypass surgery in the 1980s was done more effectively with less morbidity and mortality [7]. To date, the effects of coronary angioplasty on employment have been less intensively investigated [8-12]. We compared return-to-work rates in patients treated with angioplasty, bypass surgery, and medical therapy between 1986 and 1990 while accounting for the effects of nonmedical factors on long-term employment rates [13]. Methods Patients We studied patients with suspected coronary artery disease who were referred to Duke University Medical Center for diagnostic cardiac catheterization between March 1986 and June 1990. Patients were eligible for this study if they were younger than 65 years at the time of catheterization, were referred for evaluation of chest pain or equivalent ischemic symptoms, did not require intensive cardiac care at the time of their catheterization procedure, and had no previous angioplasty or bypass surgery. Patients found at angiography to have normal coronary arteries or clinically insignificant coronary artery disease ( 50% stenosis) were excluded. As described previously [13], 2022 patients meeting these criteria were enrolled in a prospective study of economic and quality-of-life outcomes. Of these, 1252 were employed at the time of their catheterization, and they form the basis of the present investigation of employment outcomes. Treatment groups were defined according to the first revascularization procedure the patient received within 60 days of catheterization: angioplasty (n = 312), bypass surgery (n = 449), and medical treatment (n = 491). The median time from catheterization to revascularization was 1 day for the patients who had angioplasty (25th percentile to 75th percentile, 1 to 3 days) and 5 days for patients who had bypass surgery (3 to 9 days). Data Collection and Information System The computerized information system used in this study, the Duke Cardiovascular Disease Databank, has been described previously [14]. Demographic, clinical, and angiographic data were collected prospectively as part of the routine patient care process [15]. Baseline quality-of-life and job-related data were usually collected on the day before catheterization or, less frequently, after the catheterization but before referral for revascularization using a self-administered questionnaire, as previously described [13]. Functional status was assessed with the Duke Activity Status Index, a 12-item scale developed and validated against measured maximal exercise oxygen consumption. The Duke Activity Status Index assesses whether patients can do a spectrum of activities without difficulty, and in this study, it was scored from 0 to 12, with higher scores indicating better functional capacity [13, 16]. General health perceptions were assessed by a four-level ordinal question that asked about the effect of the patient's health on function. Psychological status was assessed with four visual analog scales graded from 0 to 10 (lower scores indicate better function) from the General Well-Being Schedule covering anxiety, depression, health concerns, and energy [17]. Socioeconomic status was assessed with questions on years of education, marital status, spouse occupation, number of dependents, and income. The patient's job was assigned to one of six job classes using standard criteria [18]: managerial and professional; technical and sales; service; farming, forestry, and fishing; precision production, craft, and repair; and operators, fabricators, and laborers. The physical demands of the job were categorized using U.S. Department of Labor criteria into one of four classes (sedentary, light, medium, and heavy) [19]. The psychological stress of the job and the decision latitude available to the patient at work were measured using scales designed by Karasek and colleagues [20, 21]. Follow-up All patients were contacted by mailed questionnaire or telephone interview at 1 year and were asked to complete a battery of quality-of-life and job status questions similar to those administered at baseline. Follow-up was 98% complete. Because the date of return to work was not included in this follow-up questionnaire, we did additional follow-up in a subset of patients to collect this data. Seventy-two patients who had returned to work (25 receiving medical treatment; 24, bypass surgery; and 23, angioplasty) were randomly selected from the December 1989 to June 1990 cohort and were contacted by telephone to determine the date of return to work, so that the time interval from cardiac catheterization until initial return to work (full- or part-time) could be calculated. Data Analysis Discrete variables were summarized with percentages and continuous variables were summarized with medians and interquartile ranges (25th to 75th percentile). In this study, the binary logistic regression model [22] was used to test for differences among treatment groups in 1-year work status, unadjusted and adjusted for previously identified independent predictors of follow-up work status [13]. Patients who died before their 1-year follow-up (n = 27) were deleted from the final analysis. Including these patients (3 receiving angioplasty; 9, bypass surgery; and 15, medical treatment) and counting them as not working at 1 year did not alter the results. Differences among the treatment groups in time to return to work were tested using the Kruskal-Wallis test. In order to estimate the economic value of those days lost from work and the potential impact of an earlier return to work, we multiplied each patient's weekly income (calculated from the midpoint of the patient's annual income range ascertained at the baseline pretreatment assessment) by the number of weeks lost from work by that patient. To eliminate the potential effect on these results of slight imbalances in income distribution among treatments, we repeated the calculations using the average weekly income for the entire 70 patient sample in place of the individual income values. Both time until initial return to work and the dollar value of that lost productivity were plotted graphically using Kaplan-Meier methods [23] to display the total distribution of those variables by treatment group. Results Baseline characteristics of the three treatment groups differed in medical factors and in several nonmedical factors shown to predict subsequent work outcomes (Table 1, Table 2, and Table 3). Overall, the angioplasty group was significantly younger, had fewer previous myocardial infarctions, had less congestive heart failure, and had less extracardiac vascular disease but had a higher prevalence of unstable angina than the patients who were treated medically or had bypass surgery (Table 1). Coronary anatomy also differed substantially (Table 2), with more one-vessel disease in the angioplasty group and more three-vessel and left-main disease in the bypass surgery group. In addition, patients who had angioplasty had the highest ejection fractions, and patients receiving medicine had the lowest. Table 1. Comparison of Baseline Demographic and Clinical Characteristics by Treatment Group* Table 2. Comparison of Catheterization Results by Treatment Group Table 3. Comparison of Baseline Functional, Socioeconomic, and Psychological Characteristics by Treatment Group* Patients who had angioplasty had the highest functional status at the time of initial evaluation (see Table 3); patients who received medicine had intermediate levels; and patients who had bypass surgery had the lowest functional status [median of six activities done without difficulty compared with five activities and four activities, respectively]. Seventy-seven percent of patients who had angioplasty reported that their health caused no or only mild limitation of general functioning compared with 68% for patients who received medicine and 60% of patients who had bypass surgery. The three groups were similar, however, in terms of the socioeconomic predictors of work status (see Table 3). The median education level for all three groups was completion of high school, and the percentages who were married and who had a working spouse were also similar. In addition, the number of dependents in the household and the income did not differ by treatment group. The three treatment groups were also essentially identical at baseline in psychological status, with similar degrees of anxiety, depression, energy levels, and health concerns. Further, the three treatment groups had similar types of employment and similar physical and psychological demands on the job (Table 4). Particularly, the percentage of each group with heavy physical job demands was the same, as were the scores on the job psychological-demands scale. Table 4. Comparison of Job Characteristics by Treatment Group* Overall, at 1 year, 84% of patients who had angioplasty were still employed, compared with 79% of patients who had bypass surgery and 76% of patients receiving medicine. Employment rates for patients who had angioplasty and patients receiving medicine were different (P =