Detection of Potential Prescribing Cascades in Multimorbid Older Patients Hospitalised with Acute Illness—An Observational Prospective Prevalence Study

Background: Prescribing cascades occur when a new drug is prescribed to treat an adverse drug event caused by an existing medication, resulting in unnecessary, or potentially hazardous additional drugs. To date, there are no published studies assessing the prevalence of prescribing cascades in older hospitalised adults. Objective: To investigate the prevalence of prescribing cascades in hospitalised older adults. Methods: We conducted a prospective observational study of adults aged ≥ 65 years with multimorbidity and polypharmacy presenting to hospital with acute unselected medical or surgical illness. Prescribing cascades were identified using two predefined validated explicit cascade lists, i.e. ThinkCascades, and a list derived from a recently published systematic review of prescribing cascades in community-dwelling adults, referred to here as the ‘Doherty list’. Potential prescribing cascades were classified as ‘definite’, ‘probable’, ‘possible’, ‘uncertain’ or ‘indeterminate’ according to pre-specified criteria. Results: The study included 385 consecutive patients (55.1% female, mean age 80.2 years, standard deviation 7.3 years). A total of 281 potential prescribing cascades (drug A → drug B) were identified in 152 patients (39.4%). Probable or possible prescribing cascades were identified in 48 patients (12.4%) using the Doherty list and in 44 patients (11.4%) using ThinkCascades. Patients exposed to potential prescribing cascades experienced greater levels of polypharmacy than patients not exposed to prescribing cascades (median interquartile range [IQR] of 12 [9–14] daily drugs versus 9 [IQR 7–11], p < 0.001). Conclusions: Potential prescribing cascades were highly prevalent in older hospitalised adults. Practical tools are needed to assist prescribers in prevention, recognition and management of inappropriate prescribing cascades.