Statin prescribing in Australia: socioeconomic and sex differences - A cross-sectional study

Abstract

OBJECTIVE: 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. DESIGN: Cross-sectional study using data on statin prescribing by age, sex and patient postcode for the period May to December 2002. SETTING AND PARTICIPANTS: The Australian population, stratified by sex and quintile of Index of Relative Socio-Economic Disadvantage (IRSD). MAIN OUTCOME MEASURES: Age-standardised rates of statin scripts per 1000 population per month for each sex and IRSD quintile. RESULTS: 9.1 million prescriptions for statins were supplied between May and December 2002, for a total cost of $570 million. 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). Conclusions: 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 MJA 2004; 180: 229–231 measure of risk).