Risk factors for 30-day readmission in patients with ischemic stroke: a systematic review and meta-analysis

BACKGROUND: The aim of this study was to identify risk factors for 30-day readmission in ischemic stroke survivors, with an attempt to improve post-discharge care and lower the 30-day readmission rate. METHODS: Seven databases were searched from inception to April 30, 2021. Retrospective or prospective observational studies and interventional studies focusing on 30-day readmission risk factors in patients with ischemic stroke were included. Two authors independently screened the literature and evaluated the quality of the studies using the Newcastle-Ottawa scale (NOS). The pooled effect size was estimated using the odds ratio (OR), and the corresponding 95% confidence interval (CI) was calculated. The Cochrane Q (χ2) and I2 tests were used to assess heterogeneity among studies, and each risk factor was tested for its robustness using fixed- or random-effects models. RESULTS: A total of 17 retrospective observational studies from the United States (n=10), China (n=2), Republic of Korea (n=2), Norway (n=2), and Australia (n=1), comprising a total of 1,829,964 patients, were included. The 30-day readmission rates of ischemic stroke survivors ranged from 1.41% to 27.64%, with a mean value of 10.66%±6.87%. We finally identified 6 risk factors: history of stroke (OR, 1.33; 95% CI: 1.08-1.64; P=0.007), diabetes mellitus (OR, 1.15; 95% CI: 1.13-1.17; P<0.001), hypertension (OR, 1.10; 95% CI: 1.07-1.13; P<0.001), atrial fibrillation (OR, 1.26; 95% CI: 1.23-1.29; P<0.001), heart failure (OR, 1.59; 95% CI: 1.56-1.63; P<0.001), and age, among which age was determined by descriptive analysis. Four risk factors were ruled out: hyperlipidemia (OR, 1.01; 95% CI: 0.87-1.17; P=0.91), coronary artery disease (OR, 0.83; 95% CI: 0.73-0.96; P=0.009), smoking (OR, 0.97; 95% CI: 0.83-1.14; P=0.71), and gender (female, OR, 0.97; 95% CI: 0.96-0.98; P<0.001). DISCUSSION: The 30-day readmission rates of ischemic stroke survivors ranged from 1.41% to 27.64% and remained challenging. We found that stroke history, diabetes mellitus, hypertension, atrial fibrillation, heart failure, and advanced age were risk factors for 30-day readmission, whereas hyperlipidemia, coronary artery disease, smoking, and gender were not. All the studies included in this analysis were case-control studies, and thus causality cannot be inferred. Furthermore, recall bias may be present.