Objectives: To investigate medication changes for older patients admitted to hospital and to explore associations between patient characteristics and polypharmacy.
Design: Prospective cohort study.
Participants and setting: Patients aged 70 years or older admitted to general medical units of 11 acute care hospitals in two Australian states between July 2005 and May 2010. All patients were assessed using the interRAI assessment system for acute care.
Main outcome measures: Measures of physical, cognitive and psychosocial functioning; and number of regular prescribed medications categorised into three groups: non-polypharmacy (0-4 drugs), polypharmacy (5-9 drugs) and hyperpolypharmacy (≥ 10 drugs).
Results: Of 1220 patients who were recruited for the study, medication records at admission were available for 1216. Mean age was 81.3 years (SD, 6.8 years), and 659 patients (54.2%) were women. For the 1187 patients with complete medication records on admission and discharge, there was a small but statistically significant increase in mean number of regular medications per day between admission and discharge (7.1 v 7.6), while the prevalence of medications such as statins (459 [38.7%] v 457 [38.5%] patients), opioid analgesics (155 [13.1%] v 166 [14.0%] patients), antipsychotics (59 [5.0%] v 65 [5.5%] patients) and benzodiazepines (122 [10.3%] v 135 [11.4%] patients) did not change significantly. Being in a higher polypharmacy category was significantly associated with increase in comorbidities (odds ratio [OR], 1.27; 95% CI, 1.20-1.34), presence of pain (OR, 1.31; 1.05-1.64), dyspnoea (OR, 1.64; 1.30-2.07) and dependence in terms of instrumental activities of daily living (OR, 1.70; 1.20-2.41). Hyperpolypharmacy was observed in 290/1216 patients (23.8%) at admission and 336/1187 patients (28.3%) on discharge, and the proportion of preventive medication in the hyperpolypharmacy category at both points in time remained high (1209/3371 [35.9%] at admission v 1508/4117 [36.6%] at discharge).
Conclusions: Polypharmacy is common among older people admitted to general medical units of Australian hospitals, with no clinically meaningful change to the number or classification (symptom control, prevention or both) of drugs made by treating physicians.