Prevalence and incidence of hypertension from 1995 to 2005: a population-based study

Abstract

Background: Researchers have predicted that there will be a relative increase of 24% in the prevalence of hypertension in developed countries from 2000 to 2025. Hypertension is a leading risk factor for death, stroke, cardiovascular disease and renal disease. Thus, accurate estimates of the prevalence of hypertension in a population have important implications for public policy. We sought to assess whether the estimated increase in the prevalence of hypertension has been underestimated.

Methods: We performed a population-based cohort study using linked administrative data for adults aged 20 years and older in Ontario, Canada's most populous province with more than 12 million residents. Using a validated case-definition algorithm for hypertension, we examined trends in prevalence from 1995 to 2005 and in incidence from 1997 to 2004.

Results: The number of adults with hypertension more than doubled from 1995 to 2005. The age- and sex-adjusted prevalence increased from 153.1 per 1000 adults in 1995 to 244.8 per 1000 in 2005, which was a relative increase of 60.0% (p < 0.001). The age- and sex-adjusted incidence of hypertension increased from 25.5 per 1000 adults in 1997 to 32.1 per 1000 in 2004, which was a relative increase of 25.7% (p < 0.001).

Interpretation: Our findings indicate that the rise in hypertension prevalence will likely far exceed the predicted prevalence for 2025. Public health strategies to prevent and manage hypertension and its sequelae are urgently needed.

Figure 1: Prevalence of hypertension in the province of Ontario from 1995 to 2005. We used a logistic regression model to adjust for age, sex, residence location (urban v. rural), socioeconomic status, presence of diabetes, 5-year history of cardiovascular disease, Charlson Comorbidity Index score, and interaction terms between age and sex. Yearly rates are based on prevalence as of Mar. 31 of each year. Results of the Pearson correlation test p < 0.001.

Figure 2: Incidence of hypertension in the province of Ontario from 1997 to 2004. We used a logistic regression model to adjust for age, sex, residence location (urban v. rural), socioeconomic status, presence of diabetes, 5-year history of cardiovascular disease, Charlson Comorbidity Index score, and interaction terms between age and sex. Yearly rates are based on prevalence as of Mar. 31 of each year. Results of the Pearson correlation test were p < 0.001 overall and for women and men aged 20–49 years, p = 0.007 for women aged 50 years and older and p = 0.001 for men aged 50 years and older.