Statin prescribing in Australia: socioeconomic and sex differences

Abstract

To assess if there are any differences in statin prescribing across Australia by socioeconomic status or sex and to relate prescribing rates to coronary heart disease (CHD) mortality rates. Cross-sectional study using data on statin prescribing by age, sex and patient postcode for the period May to December 2002. The Australian population, stratified by sex and quintile of Index of Relative Socio-Economic Disadvantage (IRSD). Age-standardised rates of statin scripts per 1000 population per month for each sex and IRSD quintile. 9.1 million prescriptions for statins were supplied between May and December 2002, for a total cost of 570 million dollars. The age-standardised rates for statin prescribing in women varied from 56.9 (95% CI, 56.6-57.2) scripts per 1000 population per month in the most disadvantaged socioeconomic quintile through 53.4 (95% CI, 53.0-53.7), 50.3 (95% CI, 50.0-50.6), 48.4 (95% CI, 48.1-48.7) to 46.3 (95% CI, 46.0-46.6) in the least disadvantaged quintile. For men the figures were 52.6 (95% CI, 52.3-52.9), 50.9 (95% CI, 50.6-51.2), 48.8 (95% CI, 48.6-49.1), 47.7 (95% CI, 47.4-47.9), and 51.9 (95% CI, 51.6-52.2). There was a significant linear association between statin prescribing and CHD mortality by quintile of socioeconomic disadvantage in women (weighted least squares slope, 0.380; 95% CI, 0.366 to 0.395; P < 0.0001), but not in men (slope, -0.002; 95% CI, -0.010 to 0.006; P = 0.65). Our results suggest that in men there is either overprescribing of statins in the highest socioeconomic quintile or underprescribing in the lowest. Furthermore, contrary to expectation, women - relative to men - are prescribed statins at higher rates at lower levels of risk (using CHD deaths as a proxy measure of risk).