Excess risk of diabetes in persons with hypertension.

Problem: Persons with hypertension appear to be at increased risk of diabetes, an important predictor of cardiovascular disease. Whether, and to what extent, this risk may vary across subgroups defined on the basis of important clinical characteristics has not been well characterized.

Methods: Study population included members of Kaiser Permanente Northwest Region, a large health maintenance organization, aged > or = 35 years and free of diabetes in 1998. Persons in the study population were stratified based on whether or not they had hypertension, and onset of diabetes was ascertained over a 6-year period beginning January 1999. Excess risk of diabetes was characterized in terms of risk differences between persons with and without hypertension, and was estimated on an overall basis and for subgroups defined on the basis of age, sex, and body mass index (BMI).

Results: Study population totaled 104,368; 44% had hypertension. Relative risk (RR) of developing diabetes was 2.7 (95% CI: 2.6-2.8) for those with vs. without hypertension [21.0 (95% CI: 20.7-21.4) vs. 7.8 (95% CI: 7.6-8.0) per 1000 person-years, respectively]. Adjusted for age, sex, and BMI, RR of diabetes was 1.8 (95% CI: 1.7-1.9). With one exception (men, aged > or = 75 years), risk of diabetes was higher across all age and BMI strata for both men and women with vs. without hypertension; differences in risk were greatest among those with high BMI (> or = 35 kg/m(2)). Across BMI strata, RR of developing diabetes was generally higher at younger ages.

Conclusion: All persons with hypertension, irrespective of age, sex, and BMI, are at elevated risk of developing diabetes. Men and women with hypertension who are overweight or obese are at substantially elevated risk of diabetes, regardless of age, and should be monitored especially closely for the development of this disease.