Mortality among patients with hypertension from 1995 to 2005: a population-based study

Abstract

Background: We have reported that the prevalence of diagnosed hypertension increased by 60% from 1995 to 2005 in Ontario. In the present study, we asked whether this increase is explained by a decrease in the mortality rate.

Methods: We performed a population-based cohort study using linked administrative data for Ontario, a Canadian province with over 12 million residents. We identified prevalent cases of hypertension using a validated case-definition algorithm for hypertension, and we examined trends in mortality from 1995 to 2005 among adults aged 20 years and older with hypertension.

Results: The age- and sex-adjusted mortality among patients with hypertension decreased from 11.3 per 1000 people in 1995 to 9.6 per 1000 in 2005 (p < 0.001), which is a relative reduction of 15.5%. We found that the relative decrease in age-adjusted mortality was higher among men than among women (-22.2% v. -7.3%, p < 0.001).

Interpretation: Mortality rates among patients with hypertension have decreased. Along with an increasing incidence, decreased mortality rates may contribute to the increased prevalence of diagnosed hypertension. Sex-related discrepancies in the reduction of mortality warrant further investigation.

Figure 1: Annual crude and multivariable adjusted mortality rates among people with hypertension. Yearly rates are based on death by Mar. 31 of each year. Data were adjusted by logistic regression for age, sex, rural residence location, socioeconomic status, diabetes, 5-year history of cardiovascular disease, Charlson score and interaction between age and sex. The adjusted trends for overall and men were significant (p < 0.001), as was the adjusted trend for women (p < 0.012).