C-reactive protein implications in new-onset hypertension in a healthy population initially aged 65 years: the Proof study

Background Because inflammation is known to be related with several cardiovascular diseases, we sought to determine whether C-reactive protein (CRP) might precede the onset of hypertension. Methods The study population was selected from the Proof study cohort including 1011 individuals initially aged 65 years at baseline and followed for 7 years. CRP, ambulatory blood pressure measurement (ABPM) and casual blood pressure were repeatedly measured during examination. Normotensive individuals were selected according to different measurements of blood pressure, self-reported history of hypertension and use of anti hypertensive treatment. Results Among 335 individuals, considered normotensive at baseline with ABPM (threshold 135/85 mmHg), with no history of hypertension and no use of anti hypertensive treatment, the incidence of hypertension was 9.9% 2 years later. The 2-year risk for new-onset hypertension was 18% greater for 1 mg/l increment of CRP (odds ratio, 1.18; 95% confidence interval, 1.01 - 1.39). This relationship remained after adjustment for low-density lipoprotein cholesterol, BMI and change in CRP between the two examinations but not after adjustment for 24-h systolic ABPM. Among the 160 individuals considered normotensive at baseline with an additional criterion (casual blood pressure below 140/90 mmHg), the incidence of hypertension was 26.9% 2 years later. The 2-year risk for new-onset hypertension was 52% greater for 1 mg/l increment of CRP (odds ratio, 1.52; 95% confidence interval, 1.17 - 1.96) after adjustment for systolic ABPM, change in CRP and BMI. Conclusion An elevated baseline CRP value precedes new-onset hypertension at an early stage among an elderly healthy population. Whether CRP measurement can ease the detection of patients likely to develop clinical hypertension remains to be determined. J Hypertens ;27:736-743 (C) 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins.