Association of Poor Sleep Quality with Risk Factors after Coronary Artery Bypass Graft Surgery—a Prospective Cohort Study

Fragmented sleep is a daunting experience and a common health problem with high prevalence among patients 3 months after coronary artery bypass grafting (CABG). However, the potential predictors on poor seep quality remains unexplored. The main purpose of this study was to determine the predictors of poor sleep quality among patients 3 months after CABG. A prospective cohort study is a part of the randomized controlled trial between 2012 and 2013 in which 400 adult patients undergoing elective CABG were being randomly sampled as per the inclusion criteria followed up at 3 months after CABG surgery in the cardiovascular outpatient clinic of a tertiary-care hospital. The study was conducted according to the Declaration of Helsinki and was approved by the institutional ethical committee. All participants gave written informed consent on having received detailed information on the study. Demographic and clinical data were obtained from medical records at the time of CABG. The data on sleep quality were collected by using the Pittsburgh Sleep Quality Index and state anxiety was evaluated utilizing state-trait anxiety inventory (STAI-YI fo3rm). Multivariable logistic regression examined the association between the postoperative poor sleep quality and clinical, preoperative state anxiety, and angina. The significant variables are chosen based on the P-value associated with the significant level of model that lies on alpha = 0.05. Logit determination and the correlation between the variables are also discussed for further analysis. A total of 187 patients (mean age 55.6 +/- 12.05 years) completed the questionnaire. Most patients (78%) reported poor sleep quality (4.23 +/- 1.24) (PQSI score of less than 5). There was a strong relationship between PQSI and state anxiety. The higher state anxiety among 68% of patients with the mean score (53.51 +/- 9.55) had 6.42 (95% CI 3.04-9.61) times the odds of being classified as high risk for sleep disturbance. There are 3 factors that most significant of the 8 factors tested were identified as having influence significantly on the poor sleep quality. These factors are diabetes (OR 1.186, 95% CI 1.016-1.097, P >.01), body mass index > 30 kg/m(2) (OR 2.36, 95% CI 1.041-1.172, P > .05), sedentary lifestyle (OR 1.091, 95% CI 1.016-1.159, P >.01), and preoperative state anxiety (OR 1.186, 95% CI 1.074-1.115, P >.01). Even though the body mass index>30 kg/m(2), sedentary lifestyle, and diabetes were significantly associated with sleep quality, the only factor with more significantly related to poor sleep quality was preoperative state anxiety which is the strong predictor of poor sleep quality. Hence, early recognition of predictors and careful management of poor sleep quality is warranted.