Effect of age, gender, ethnicity, socioeconomic status and region on dispensing of CVD secondary prevention medication in New Zealand: the Atlas of Health Care Variation CVD cohort (VIEW-1).

Background: Triple therapy with anti-platelet/anti-coagulant, blood pressure (BP)-lowering, and statin medications improves outcomes in atherosclerotic cardiovascular disease (CVD). However, in practice there is often a substantial evidence-practice gap, with sub-optimal initiation and longer-term adherence. Our aim was to enumerate a contemporary national cohort of people with significant CVD and report the variation in CVD secondary prevention dispensing by demographic variables.

Methods: Using anonymised linkage of national data sets, we identified 86,256 individuals, alive and residing in New Zealand at the end of 2010, aged 30-79 years who were hospitalised for an atherosclerotic CVD event or procedure in the previous10 years. This cohort was linked to the national pharmaceutical dispensing dataset to assess dispensing of CVD prevention medications during the 2011 calendar year. Adequate dispensing was defined as being dispensed a drug in at least 3 of the 4 quarters of the year. Multivariate regression was used to identify independent predictors of adequate dispensing.

Results: 59% were maintained on triple therapy, 77% on BP-lowering medication, 75% on anti-platelet/anti-coagulants and 70% on statins. From multivariate analysis, patients less than 50 years were about 20% less likely than older patients and women were 10% less likely than men to be maintained on triple therapy. Indian patients were about 10% more likely to be maintained on triple therapy than NZ European/Others. Those living in the Southern Cardiac Network region of New Zealand had slightly higher rates of triple therapy than National Cardiac Regions further north.

Conclusions: The significant under-utilisation of safe and inexpensive secondary prevention medication, particularly in younger people and women, provides an opportunity to improve CVD outcomes in this easily identifiable high-risk population.