Assessment of changes in general health status using the short-form 36 questionnaire 1 year following coronary artery bypass grafting

OBJECTIVE: The problem addressed in the study was to gain a greater understanding of the health benefits of coronary artery bypass grafting (CABG). The purpose of the study was to assess general health status, using the short-form (SF)-36 questionnaire, approximately 12 months following CABG, and to document any associations between pre-operative health status, level of social support, coronary artery disease (CAD) risk factors, CAD symptom severity and post-operative health status. METHODS: The study was prospective and observational in design and included assessments at two time points, namely pre-operatively in a hospital outpatient department (1995-1996) and post-operatively at home (1996-1997). Two hundred and fourteen patients awaiting elective CABG were recruited a month before the expected date of operation. Pre-operative assessment included: (1), severity of symptoms; (2), CAD risk factors; (3), SF-36 questionnaire; and (4), social activities questionnaire. Post-operative assessment measured health status using the SF-36 instrument (mean, 16.4 months). Correlation and multiple linear regression analyses were used to identify factors associated with improved health status following CABG. RESULTS: Two hundred and fourteen patients were assessed pre-operatively and underwent CABG. There was a 4.8% 30-day mortality rate, and 183 patients were followed for a mean of 16.4 months after CABG. SF-36 scores following CABG were improved across all of the eight domains (P<0.001). A higher social network score and higher pre-operative health status were associated with improved health status. Patients with lower health levels (SF-36 scores) prior to CABG were less likely to gain improvement in health (SF-36 scores) following CABG. Lower SF-36 scores following operation were influenced by the presence of diabetes mellitus, cigarette smoking, younger age, a high socio-economic deprivation category and higher alcohol intake. Many patients had uncorrected CAD risk factors at pre-operative assessment. CONCLUSIONS: The SF-36 instrument was shown to be a useful and sensitive tool to assess differences and changes in the general health status of patients before and following CABG. High levels of social support were associated with improved health status post-operatively. Lower pre-operative general health status, the presence of diabetes mellitus and cigarette smoking were associated with poorer post-operative general health status.