Prevalence, awareness, treatment and control of hypertension and salt intake in Portugal

Abstract

To determine prevalence, awareness, treatment and control of hypertension and the 24-h sodium excretion (24h-UNa) in the Portuguese adult population and to examine their changes from a similar study done in 2003. A population-based cross-sectional survey conducted in 2011-2012. A multistage-stratified (by age and sex) sampling method was used to select a representative sample of the 18-90-year-old population yielding 3720 participants (52.6% women, 97.1% Caucasians). Hypertension was defined as a SBP of at least 140 mmHg or DBP of at least 90 mmHg [average of 2-3 blood pressure (BP) measurements by trained observers with OMRON M6] or reported knowledge or treatment with antihypertensive drugs at the first visit (V1). A complete clinical information was obtained with a standard questionnaire. This procedure was repeated 10-15 days after visit 2 (V2) and 24-h urinary sample was collected for 24h-UNa, 24-h potassium excretion and creatinine excretion. The overall prevalence of hypertension at V1 was 42.2% (44.4% in men, 40.2% in women) (42.1% in 2003). The age-specific prevalence of hypertension was 6.8, 46.9 and 74.9% in people below 35 years, 35-64 years and above 64 years. Comorbidities were 2.2-6.3 times more common in hypertensive patients vs. normotensive individuals. Overall, among the hypertensive patients, 76.6% were aware of the hypertension condition, 74.9% were treated and 42.5% were controlled (BP <140/90 mmHg), that is, respectively, 1.7, 1.9 and 3.8 times higher vs. data in 2003, with lower values in men vs. women and younger vs. older people. Global mean BP was 127.4/74.6 ± 17.7/10.5 vs. 134.7/80.4 ± 21.2/14.1 mmHg in 2003. From V1 to V2, control of hypertension increased on average by 14.8%. Multivariate analysis showed that age and BMI were independently associated with prevalence of hypertension. 24h-UNa (84% valid urinary samples) was 182.5 ± 64.7 mmol/day (10.7 g salt/day) and 24-h potassium excretion 75.2 ± 26.1 mmol/day. 24h-UNa was higher in patients with hypertension than in normotensive individuals (185.4 ± 64.8 vs. 177.8 ± 64.5 mmol/day; P < 0.02) and correlated with SBP (r = 0.05), age (r = 0.08) and BMI (r = 0.10) (P < 0.01). Hypertension prevalence among Portuguese adults remained stable in the past decade, but proportions of awareness, treatment and control of hypertension improved significantly. Salt intake is still high being almost double the WHO recommendations.