Factors related to under-treatment of secondary cardiovascular risk, including primary healthcare: Australian National Health Survey linked data analysis

Objective: To inform national evidence gaps on cardiovascular disease (CVD) preventive medication use and factors relating to under-treatment - including primary healthcare engagement - among CVD survivors in Australia. Methods: Data from 884 participants with self-reported CVD from the 2014-15 National Health Survey were linked to primary care and pharmaceutical dispensing data for 2016 through the Multi-Agency Data Integration Project. Logistic regression quantified the relation of combined blood pressure- and lipid-lowering medication use to participant characteristics. Results: Overall, 94.8% had visited a general practitioner (GP) and 40.0% were on both blood pressure- and lipid-lowering medications. Medication use was least likely in: women versus men (OR=0.49[95%CI:0.37-0.65]), younger participants (e.g. 45-64y versus 65-85y: OR=0.58[0.42-0.79])and current versus never-smokers (OR=0.73[0.44-1.20]). Treatment was more likely in those with >= 9 versus <= 4 conditions (OR=2.15[1.39-3.31]), with >= 11 versus 0-2 GP visits/year (OR=2.62[1.53-4.48]) and with individual CVD risk factors (e.g. high blood pressure OR=3.13 [2.34-4.19]) versus without); the latter even accounting for GP service-use frequency. Conclusions: Younger people, smokers, those with infrequent GP visits or without CVD risk factors were the least likely to be on medication. Implications for public health: Substantial under-treatment, even among those using GP services, indicates opportunities to prevent further CVD events in primary care.