Abstract 1356: Exercise Capacity Predicts Progression From Pre-hypertension to Hypertension in African American Men
Background: Predictors of the progression from pre-hypertension to hypertension (HTN) have not been adequately defined, especially in African-Americans. Since fitness is associated with cardiovascular health, we assessed the association between fitness and the rate of progression to HTN in pre-hypertensive African-American men.
Methods: From March of 1985 to June 2007, we identified 1,081pre-hypertensive African-American men (mean age: 54±12) who underwent an exercise evaluation to rule out ischemia. All had a normal exercise response, were not receiving cardiac or antihypertensive medications and had resting blood pressure within the established pre-hypertension criteria. We established four fitness categories based on the age and MET level achieved. Individuals who achieved a peak MET level within the lowest 20th percentile of their respective age group (mean: 5.2 MET) comprised the Lowest-Fit category (n=210). Those with a MET level between the 21st and 50th percentile (mean: 7.1 MET) comprised the Low-Fit category (n=359). Subjects with a MET level between 51st and 85th percentile (mean: 8.8 MET) comprised the Moderate-Fit category (n=352) and those with a MET level above the 85th percentile (mean: 10.1 MET), comprised the High-Fit category (n=160).
Results: The overall rate of progression from pre-hypertension to HTN within the follow-up period of 8.2±5.8 years was 33.3% and the yearly rate 4.1%. The highest rate (41.4%) was observed in the Lowest-Fit category, followed by 39.3%, 28.4% and 20% for the Low, Moderate and High-Fit categories respectively. Cox proportional hazard analysis (adjusted for age, BMI, smoking, resting BP, and diabetes) revealed a 10% lower risk for developing HTN for every 1-MET increase in exercise capacity. When compared to the High-Fit category, the risk for hypertension was 66% higher (hazard ratio= 1.66; CI: 1.1–2.4) in the Low-Fit and 82% higher (hazard ratio= 1.82; CI: 1.1–2.7) in the Lowest-Fit category individuals.
Conclusions: Exercise capacity is inversely related to the risk for developing HTN. The risk was 10% lower for each 1-MET increase in exercise capacity. The relative risk for developing HTN in the two lowest fit categories was approximately 60% to 80% higher when compared to the High-Fit.