Utilization of cardiovascular drugs (blood pressure lowering drugs, lipid lowering drugs and nitrates) and mortality from ischaemic heart disease andstroke - An ecological analysis based on Sweden's municipalities

Objective: To perform an ecological study in an effort to generate question s concerning the preventive impact of various cardiovascular drugs on morta lity from stroke and ischaemic heart disease (IHD) in the community, and to explore the association between sales of nitrates and mortality from strok e and IHD. Methods: Out-patient drug utilization (sales) of blood pressure lowering dr ugs, lipid lowering drugs and nitrates were categorized in four groups of e qual size by quartiles and compared with mortality from IHD and stroke, usi ng the group of municipalities with the lowest utilization as reference, fr om 1989 to 1993 in 283 of Sweden's 288 municipalities, by Poisson regressio n. Adjustments were made for population size, age and gender proportions, t he utilization rate of cardiovascular drugs other than the tested drug grou p and location of the municipality. Results: Compared with the group of municipalities with the lowest sales an d adjusting only for population size, mortality from IHD and stroke increas ed with the extent of utilization of blood pressure lowering drugs and nitr ates. In contrast, mortality decreased with increased utilization of lipid lowering drugs. After further adjustments by percentage of men, age structu re, geographical. location (mid-points) of the municipalities, and, as a. p roxy for cardiovascular disease, the sales of cardio- vascular drugs other than the tested drug group, the increased risk associated with blood pressu re lowering drugs disappeared, and there was a dose-response association be tween sales of diuretics and old antihypertensives and decreasing mortality , sales of nitrates continued to be associated with an increased risk, and the low mortality risk associated with sales of lipid lowering drugs persis ted. Conclusion: Lipid lowering drugs may have a preventive impact in the genera l population, but the preventive impact of blood pressure lowering drugs, w ith the exception of diuretics and old antihypertensives, may be low in man y municipalities. The safety of nitrates needs more investigation at the in dividual level.