The 10 - year risk of incident hypertension across blood pressure categories in a population based cohort study in southwestern Sweden

Abstract

The 10 - year risk of incident hypertension across blood pressure categories in a population based cohort study in southwestern Sweden Klara Lundholm Supervisors: Senior lecturer Bledar Daka, MD, PhD Professor Ulf Lindblad, MD, PhD Abstract Objective. To explore the determinants of incident hypertension, and especially the impact of baseline blood pressure category, in a representative Swedish population during 10 years follow-up. Design and method. A population based cohort study with sex ratio 1:1 and mean age 47. Blood pressures were measured and categorized according to ESH guidelines with optimal blood pressure <120/80 mmHg, normal 120-129/80-84 mmHg, high normal 130-139/85-89 mmHg, and unstable ≥140 systolic and/or ≥90 mmHg diastolic at one or two visits. Hypertension was defined as ongoing treatment or readings of ≥140 and/or ≥ 90 mmHg at three consecutive visits. Subjects with hypertension at baseline were excluded. Data were analyzed with multiple binary logistics regression. Results. At baseline, blood pressure was optimal in 633 subjects (56.1%), normal in 292 (25.9%), high normal in 141 (12.5 %) and unstable in 63 (5.6%). Within the optimal blood pressure group 18 (2.8%) converted to hypertension during follow up. Corresponding numbers for subjects with normal, high normal and unstable blood pressure were 58 (19.9%), 56 (39.7%) and 47 (74.6%) respectively. Normal, high normal and unstable baseline blood pressure were all associated with an increased risk of development to manifest hypertension compared to optimal blood pressure, with odds ratios (OR) and 95% CI of 5.4 (2.9-9.9), 12.5 (6.3-24.8) and 87.5 (33.1-231.4), respectively, independent of age and other main cardiovascular risk factors. The progression to hypertension was also independently predicted by age, BMI and family history of hypertension, with OR 1.03 (1.00-1.05), 1.12 (1.05-1.19) and 2.59 (1.59-4.23), respectively. Conclusions. Subjects with high normal or unstable blood pressure should be identified in clinical practice and evaluated for global risk accounting for family history of hypertension. Thereupon personalized advice on lifestyle modification should be given, as early prevention of cardiovascular disease.