Multimorbidity and cardiovascular prevention in primary care: Cohort study in New Zealand.

Abstract

Multimorbidity adds complexity to medication management. National guidelines in New Zealand (NZ) recommend dual therapy with blood-pressure- and lipid-lowering agents for most patients at five-year cardiovascular disease (CVD) risk ≥15% (high risk), considered at 5-14% (intermediate risk), and not generally recommended at <5% (low risk). To examine the association between multimorbidity and dispensing of dual therapy across risk strata. A cohort study among 430,286 patients aged 30-79 years without prior CVD, enrolled in the NZ Primary Health Organisation ProCare in 2014. Multivariable Poisson regression estimated relative risks (RR) for dual therapy across CVD risk groups at cohort entry. Two-year maintenance of dual therapy was then compared by multimorbidity within each risk stratum. Baseline dual therapy receipt was 1.5%, 31% and 40% in low, intermediate and high risk groups respectively. Multimorbidity was associated with greater use of dual therapy across risk groups (low risk: RR 2.90 [95% CI 2.77-3.03]; intermediate risk: RR 1.35 [95% CI 1.32-1.38]; high risk: RR 1.15 [95% CI 1.10-1.22]). Multimorbidity was also associated with higher maintenance in the low (88% vs 84%) and intermediate (90% vs 86%) risk groups (both p<0.001) and was high, irrespective of multimorbidity, in high risk (89% vs 88%; p=0.415). Patients with multimorbidity were more likely than others to be commenced on and maintain CVD prevention. However, while dispensing increased with increasing CVD risk, a large evidence-practice gap in dual therapy remained for those at high CVD risk.