Sleep disturbances and risk of hospitalization and inpatient days among older women

Study Objectives: Determine the associations of sleep disturbances with hospitalization risk among older women. Methods: One thousand eight hundred and twenty-seven women (mean age 83.6 years) participating in Study of Osteoporotic Fractures Year 16 (Y16) examination (2002-2004) linked with Medicare and/or HMO claims. At Y16 examination, sleep/wake parameters were measured by actigraphy (total sleep time [TST], sleep efficiency [SE], sleep latency [SL], and wake after sleep onset [WASO]) and subjective sleep measures (sleep quality [Pittsburgh Sleep Quality Index] and daytime sleepiness [Epworth Sleepiness Scale]) were assessed by questionnaire. Measures except TST were dichotomized based on clinical thresholds. Incident hospitalizations were determined from claims data. Results: Nine hundred and seventy-six women (53%) had ≥1 hospitalization in the 3 years after the Year 16 examination. Reduced SE (odds ratio [OR] = 2.39, 95% confidence interval [CI] 1.69-3.39), prolonged SL (OR = 1.41, 95% CI 1.11-1.78), greater WASO (OR = 1.57, 95% CI 1.28-1.93), shorter TST (OR = 1.98, 95% CI 1.42-2.77) and poorer sleep quality (OR = 1.33, 95% CI 1.07-1.65) were each associated with a higher age and site-adjusted odds of hospitalization; associations were attenuated after multivariable adjustment for traditional prognostic factors with the OR for reduced SE (OR = 1.60, 95% CI 1.08-2.38) and shorter TST (OR = 1.63, 95% CI 1.12-2.37) remaining significant. Among women who were hospitalized, greater WASO (rate ratio [RR] = 1.20, 95% CI 1.04-1.37) and poorer sleep quality (RR = 1.18, 95% CI 1.02-1.35) were each associated with a greater age and site-adjusted RR of inpatient days, but associations did not persist after multivariate adjustment. Conclusions: Older women with sleep disturbances have an increased risk of hospitalization partially attributable to demographics, poorer health status, and comorbidities.