Detection of Prescribing Cascades in Multimorbid Older Patients Hospitalized with Acute Unselected Illness

Background Prescribing cascades (PCs) occur when a new medication is prescribed to treat an unrecognized side-effect of another medication. PCs represent an important but often underrecognized aspect of inappropriate prescribing in older people with multimorbidity and associated polypharmacy and can result in avoidable morbidity and mortality. Numerous PCs are described in the literature, however, there are no prospective studies describing PC prevalence in older people. Therefore, we aimed to investigate the prevalence of PCs in acutely hospitalized older adults. Methods We undertook a prospective observational study, including adults ≥65years with polypharmacy (≥5 daily drugs) and multimorbidity (≥3 chronic disorders). Prescription medication lists were examined for the co-prescription of 31 drug pairs according to two pre-defined PC lists– ThinkCasades1 and of the explicit cascades published by Doherty et al2. PCs were defined as ‘definite’, ‘probable’, ‘possible’, ‘uncertain’ or ‘indeterminate’ according to specific criteria. Results We obtained prospective data on 300 patients (56% female, mean age 80.4yrs SD 7.2). 233 drug pairs were prescribed in the sequence of drug A → drug B, these occurred in 43% (n=130) of patients. Of the 233 pairs, 38% (n=88) were probable or possible PCs and 62% (n=145) were uncertain. 45 patients (15%) had ≥1 possible or probable PCs. The most commonly identified probable/possible PCs were diuretic → overactive bladder medication and calcium channel blocker → diuretic. Patients with an identified PC experienced higher mean levels of polypharmacy than patients with no PCs (11.7, SD 4.0 vs 9.6, SD 3.1, T= -4.97, p <0.001). Conclusion In this first-ever study to report prospective prevalence of PCs, possible or probable PCs were significantly prevalent among acutely hospitalized multimorbid older patients and were associated with higher levels of polypharmacy.McCarthy LM, et al. Drgs & aging. 2022 Oct;39(10):829-40.Doherty AS, et al. Pharmacology research & perspectives. 2022 Oct;10(5): e01008.