Why do sales of lipid-lowering drugs vary between counties in Norway? Evidence from the OPPHED Health Study 2000-2001

Abstract

Objective: To study and compare plausible factors that might explain varying sales of lipid-lowering drugs (LLDs) in the two neighbouring counties of Hedmark and Oppland in Norway, with a similar age distribution, socioeconomic structure, and access to healthcare services.

Design, setting, subjects: Cross-sectional population study comprising 10 598 attendants aged 40, 45, 60, and 75 years in the OPPHED Health Study, 2000-2001 (attendance rate 61%).

Main outcome measure: Treatment eligibility (cardiovascular morbidity and risk score), treatment frequency in treatment-eligible subgroups and treatment intensity in terms of achievement of total cholesterol (TC) goal.

Results: Proportions eligible for LLD treatment in Hedmark and Oppland were similar. There was no difference in prevalence of LLD use among participants with cardiovascular disease or diabetes (secondary prevention subgroup). However, LLD use among men in the primary prevention subgroup was higher in Hedmark compared with Oppland, 6.3% and 4.1%, respectively (p < 0.05). The same tendency was seen among women. In both sexes, more LLD users in the primary prevention subgroup achieved the TC goal in Hedmark compared with Oppland (p < 0.05).

Conclusion and implications: The proportion of the population eligible for LLD treatment in the two counties should imply similar treatment rates in both. Higher LLD treatment frequency and intensity in the primary prevention subgroup in Hedmark are probably both contributing factors that explain the higher sales of LLDs in Hedmark compared with Oppland. Feasible intervention thresholds for primary prevention with concurrent reimbursement rules should be defined in guidelines to avoid unintentional variation in LLD use in the future.