Objectives: To estimate the incidence of hypertension in people with and without prehypertension and determine the factors that predict progression to hypertension.
Methods: Data from a cohort of 25–74-year old residents of Spanish Town, Jamaica, were analysed. All participants completed a structured questionnaire and had blood pressure (BP), anthropometric measurements and venous blood sampling performed by trained personnel. Blood Pressure was classified using the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC-7) criteria.
Results: 708 persons who had the required data and were not hypertensive at baseline were included in this analysis. Mean follow-up time was 4.1 years; 28.7% of prehypertensive participants developed hypertension compared to 6.2% of normotensive participants. The unadjusted incidence rate ratio (IRR [95% CI]) for progression among prehypertensive compared to normotensive participants was 4.62[2.96, 7.43]. Among males, the rate of progression to hypertension was significantly higher for those 45–64 years old and those who were current smokers. Among females, progression was higher for age groups 25–44 years, 45–64 years, those who were overweight (BMI ≥ 25), obese (BMI ≥ 30) and current smokers. In multivariate models, prehypertension, female gender, overweight status and older age remained significantly associated with progression to hypertension among the combined prehypertensive and normotensive groups. IRR [95% CI] were: prehypertension, 3.45 [2.18–5.45]; female gender, 1.81 [1.12, 2.94]; overweight, 1.87 [1.15, 2.94]; age 45–64 years, 1.73 [1.08, 2.76]; age ≥ 65 years 2.39 [1.31, 4.34].
Conclusions: Prehypertension is associated with a three-fold increase in the incidence of hypertension. Higher BMI, age and female gender also independently predict the development of hypertension.