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A Systematic Review and Meta-Analysis Examining the Impact of Sleep Disturbance on Postoperative Delirium

Objectives: Basic science and clinical studies suggest that sleep disturbance may be a modifiable risk factor for postoperative delirium. We aimed to assess the association between preoperative sleep disturbance and postoperative delirium. Data Sources: We searched PubMed, Embase, CINAHL, Web of Science, and Cochrane from inception until May 31, 2017. Study Selection: We performed a systematic search of the literature for all studies that reported on sleep disruption and postoperative delirium excluding cross-sectional studies, case reports, and studies not reported in English language. Data Extraction: Two authors independently performed study selection and data extraction. We calculated pooled effects estimates with a random-effects model constructed in Stata and evaluated the risk of bias by formal testing (Stata Corp V.14, College Station, TX), Data Synthesis: We included 12 studies, from 1,238 citations that met our inclusion criteria. The pooled odds ratio for the association between sleep disturbance and postoperative delirium was 5.24 (95% CI, 3.61–7.60; p < 0.001 and I2 = 0.0%; p = 0.76). The pooled risk ratio for the association between sleep disturbance and postoperative delirium in prospective studies (n = 6) was 2.90 (95% CI, 2.28–3.69; p < 0.001 and I2 = 0.0%; p = 0.89). The odds ratio associated with obstructive sleep apnea and unspecified types of sleep disorder were 4.75 (95% CI, 2.65–8.54; p < 0.001 and I2 = 0.0%; p = 0.85) and 5.60 (95% CI, 3.46–9.07; p < 0.001 and I2 = 0.0%; p = 0.41), respectively. We performed Begg’s and Egger’s tests for publication bias and confirmed a null result for publication bias (p = 0.371 and 0.103, respectively). Conclusions: Preexisting sleep disturbances are likely associated with postoperative delirium. Whether system-level initiatives targeting patients with preoperative sleep disturbance may help reduce the prevalence, morbidity, and healthcare costs associated with postoperative delirium remains to be determined.