Multimorbidity, defined as two or more chronic medical conditions, leads to the use of multiple medicines, including for cardiovascular conditions. This is associated with frailty and an increased risk of medication-related harm. Hospitalised adults have higher rates of multimorbidity and frailty compared with non-hospitalised adults. The aim of this study was to examine the use of medicines for hypertension, ischaemic heart disease and atrial fibrillation among patients with multimorbidity and frailty, who are generally not well represented in clinical trials.

A cross-sectional study was performed of adults aged ≥45 years with inpatient admissions during an 18-month period. Regular medications prescribed at discharge and coding data were obtained from the electronic medical record and hospital datasets.

The prevalence of multimorbidity (using coded chronic medical conditions or the RxRisk pharmaceutical comorbidity index), frailty (using hospital frailty risk score) and polypharmacy (defined as ≥5 medicines) were calculated. The uptake of medicines recommended by the Australian Therapeutic Guidelines for patients with coded hypertension, ischaemic heart disease and atrial fibrillation was also assessed.

Two large acute care, teaching hospitals in Adelaide, South Australia.

23 980 unique patients were identified.

69% (n=16 637) of patients had multimorbidity using the coding definition compared with 94% (n=22 620) using the pharmaceutical comorbidity score. 81% (n=19 366) had polypharmacy and 46% (n=11 091) had frailty. More than 85% of patients with hypertension were taking an antihypertensive. More than 75% of patients with ischaemic heart disease were taking an antithrombotic or a lipid-lowering agent and more than 50% were taking an agent acting on the renin-angiotensin system. Over 70% of patients with atrial fibrillation without a contraindication to anticoagulation were taking an anticoagulant. Patients with multimorbidity were 11–51% more likely to be taking an antihypertensive, antithrombotic or lipid-lowering medicine for the respective cardiovascular conditions, whereas those with frailty were 31–48% less likely to be taking guideline-directed medicines for all conditions studied.

Over two-thirds of hospitalised patients with these cardiovascular conditions were taking at least one guideline-directed medicine. Medication use was generally more common in multimorbidity and less common in frailty. Outcomes studies are needed to quantify the risks and benefits of cardiovascular medicines in these patients.