Polypharmacy and anticholinergic burden are common but not independently associated with outcomes after emergency laparotomy in older adults

Anticholinergic burden (ACB) is an accumulative effect of medications with individual anticholinergic properties. ACB arising from polypharmacy is common in older adults and has been linked to poorer outcomes in a variety of clinical contexts. With more older patients undergoing surgery, there is greater exposure to higher risk individuals with polypharmacy and increased ACB, although the significance of these postoperatively is unknown. The purpose of the study was to determine the frequency of polypharmacy and accompanying ACB in older patients undergoing laparotomy and to investigate their effect on outcomes. An ambispective, observational cohort study was conducted across two UK hospitals and included patients aged ≥ 65 undergoing emergency laparotomy, as per National Emergency Laparotomy Audit (NELA) criteria, over a 2-year period. Patients with polypharmacy (≥ 5 drugs) or high ACB (ACB score ≥ 3) were identified. Primary outcome was mortality up to 1 year and secondary outcomes included postoperative complications, functional and cognitive decline, intensive care unit (ICU) admission, length of hospital stay and readmission within 30-days. A total of 144 patients were included (median age 76, 54% female) of which 42% had polypharmacy and 17% had high ACB. There was no significant difference in mortality up to 1 year following surgery between those with or without polypharmacy, nor those with or without significant ACB. Patients with polypharmacy had longer hospital stays (15 vs. 12 days, p = 0.025). There were no significant differences demonstrated for other secondary outcomes. Polypharmacy and high ACB are common in older adults undergoing emergency laparotomy but neither appeared to influence adverse outcomes apart from increased length of hospitalisation. Polypharmacy and ACB may simply be surrogate markers for age, frailty and comorbidity burden. The relationship should be further explored in larger, well-designed studies.