Association of Preoperative Anticholinergic Medication Exposure With Postoperative Healthcare Resource Use and Outcomes: A Population-based Cohort Study.

OBJECTIVE: The aim of this study was to measure the association of preoperative anticholinergic exposure with length of stay (LOS) and other outcomes in older people having elective noncardiac surgery.

SUMMARY BACKGROUND DATA: Anticholinergic medications are associated with adverse events in nonsurgical populations; the association of anticholinergic medications with outcomes in elective surgery patients is poorly described.

METHODS: We conducted a retrospective, population-based cohort study using linked administrative data in Ontario, Canada. We identified all people >65 years old, from 2003 to 2014, having major, elective noncardiac surgery. Anticholinergic medication exposure was quantified using the Anticholinergic Risk Scale (ARS). Multilevel, multivariable modeling measured the adjusted association of ARS with LOS (primary outcome), institutional discharge, readmissions, costs, and survival (secondary outcomes).

RESULTS: Of 245,410 individuals, 71,569 had anticholinergic exposure (ARS 1-2, 15.6%; ARS ≥3, 13.6%). Median LOS was 5 days (interquartile range 3-7). Using proportional hazards analysis to model time to discharge, adjusting for in-hospital death as a competing risk, and surgical risk, demographic characteristics, and comorbidities, higher ARS scores were associated with longer LOS [smaller hazard ratios (HRs) mean longer LOS; ARS 1-2: adjusted HR 0.94, 95% confidence interval (CI), 0.93-0.95, P < 0.0001; ARS ≥3: adjusted HR 0.93, 95% CI, 0.91-0.95, P < 0.0001]. Similar associations were observed for all secondary outcomes.

CONCLUSIONS: Increasing ARS scores were associated with increased LOS, decreased survival, higher rates of institutional discharge and readmission, and higher costs of care. Perioperative interventional research to reduce the anticholinergic exposure in older surgical patients is likely warranted.