Comorbidity and polypharmacy in chronic heart failure: a large cross-sectional study in primary care.

Comorbidity is common in heart failure, but previous prevalence estimates have been based on a limited number of conditions using mainly non-primary care data sources. To compare prevalence rates of comorbidity and polypharmacy in those with and without chronic heart failure due to left ventricular systolic dysfunction (LVSD). A cross-sectional study of 1.4 million patients in primary care in Scotland. Data on the presence of LVSD, 31 other physical, and seven mental health comorbidities, and prescriptions were extracted from a database of 1 424 378 adults. Comorbidity prevalence was compared in patients with and without LVSD, standardised by age, sex, and deprivation. Pharmacology data were also compared between the two groups. There were 17 285 patients (1.2%) who had a diagnosis of LVSD. Compared with standardised controls, the LVSD group had greater comorbidity, with the biggest difference found for seven or more conditions (odds ratio [OR] 4.10; 95% confidence interval (CI] = 3.90 to 4.32). Twenty-five physical conditions and six mental health conditions were significantly more prevalent in those with LVSD relative to standardised controls. Polypharmacy was higher in the LVSD group compared with controls, with the biggest difference found for ≥11 repeat prescriptions (OR 4.81; 95% CI = 4.60 to 5.04). However, these differences in polypharmacy were attenuated after controlling for the number of morbidities, indicating that much of the additional prescribing was accounted for by multimorbidity rather than LVSD per se. Extreme comorbidity and polypharmacy is significantly more common in patients with chronic heart failure due to LVSD. The efficient management of such complexity requires the integration of general and specialist expertise