Australian general practitioners initiate statin therapy primarily on the basis of lipid levels; New Zealand general practitioners use absolute risk

The cost-effectiveness of coronary calcium score-guided statin therapy initiation for Australians with family histories of premature coronary artery disease

OBJECTIVES

To compare the cost-effectiveness of coronary artery calcium (CAC) score-guided statin therapy criteria and American College of Cardiology/American Heart Association (ACC/AHA) guidelines (10-year pooled cohort equation [PCE] risk ≥ 7.5%) with selection according to Australian guidelines (5-year absolute cardiovascular disease risk [ACVDR] ≥ 10%), for people with family histories of premature coronary artery disease.

STUDY DESIGN, SETTING

Markov microsimulation state transition model based on data from the Coronary Artery calcium score: Use to Guide management of Hereditary Coronary Artery Disease (CAUGHT-CAD) trial and transition probabilities derived from published statin prescribing and adherence outcomes and clinical data.

PARTICIPANTS

1083 people with family histories of premature coronary artery disease but no symptomatic cardiovascular disease.

MAIN OUTCOME MEASURES

Relative cost-effectiveness over fifteen years, from the perspective of the Australian health care system, compared with usual care (Australian guidelines), assessed as incremental cost-effectiveness ratios (ICERs), with a notional willingness-to-pay threshold of $50 000 per quality-adjusted life-year (QALY) gained.

RESULTS

Applying the Australian guidelines, 77 people were eligible for statin therapy (7.1%); with ACVDR 5-year risk ≥ 2% and CAC score > 0, 496 people (46%); with ACVDR 5-year risk ≥ 2% and CAC score ≥ 100, 155 people (14%); and with the ACC/AHA guidelines, 256 people (24%). The ICERs for CAC-guided selection were $33 108 (CAC ≥ 100) and $53 028 per QALY gained (CAC > 0); the ACC/AHA guidelines approach (ICER, $909 241 per QALY gained) was not cost-effective. CAC score-guided selection (CAC ≥ 100) was cost-effective for people with 5-year ACVDR of at least 5%.

CONCLUSION

Expanding the number of people at low to intermediate CVD risk eligible for statin therapy should selectively target people with subclinical atherosclerosis identified by CAC screening. This approach can be more cost-effective than simply lowering treatment eligibility thresholds.

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.

Factors predicting statin prescribing for primary prevention: a historical cohort study

Background

Initiation of statins for the primary prevention of cardiovascular disease (CVD) should be based on CVD risk estimates, but their use is suboptimal.

Aim

To investigate the factors influencing statin prescribing when clinicians code and do not code estimated CVD risk (QRISK2).

Design and setting

A historical cohort of patients who had lipid tests in a database (IQVIA Medical Research Data) of UK primary care records.

Method

The cohort comprised 686 560 entries (lipid test results) between 2012 and 2016 from 383 416 statin-naive patients without previous CVD. Coded QRISK2 scores were extracted, with variables used in calculating QRISK2 and factors that might influence statin prescribing. If a QRISK2 score was not coded, it was calculated post hoc. The outcome was initiation of a statin within 60 days of the lipid test result.

Results

Of the entries, 146 693 (21.4%) had a coded QRISK2 score. Statins were initiated in 6.6% (95% confidence interval [CI] = 6.4% to 6.7%) of those with coded and 4.1% (95% CI = 4.0% to 4.1%) of uncoded QRISK2 (P<0.001). Statin initiations were consistent with National Institute for Health and Care Excellence guideline recommendations in 85.0% (95% CI = 84.2% to 85.8%) of coded and 44.2% (95% CI = 43.5% to 44.9%) of uncoded QRISK2 groups (P<0.001). When coded, QRISK2 score was the main predictor of statin initiation, but total cholesterol was the main predictor when a QRISK2 score was not coded.

Conclusion

When a QRISK2 score is coded, prescribing is more consistent with guidelines. With no QRISK2 score, prescribing is mainly based on total cholesterol. Using QRISK2 is associated with statin prescribing that is more likely to benefit patients. Promoting the routine CVD risk estimation is essential to optimise decision making.