Prevalence and determinants of resistant hypertension in a sample of patients followed in Italian hypertension centers: results from the MINISAL-SIIA study program.

The aim of this study was to detect the prevalence of resistant hypertension (RH), allowing for adherence to appropriate lifestyle measures according to European Society of Hypertension-European Society of Cardiology (ESH-ESC) 2013 guidelines, in a sample of 1284 hypertensive subjects participating at the MINISAL-SIIA study. Hypertensive patients were recruited in 47 Italian centres, recognised by the Italian Society of Hypertension. Anthropometric indexes, blood pressure and 24-h urinary sodium (Na24h) and potassium (K24h) excretion were measured. Data on antihypertensive therapy were available for 1177 (92%) subjects. The population was divided into three groups (North, Central and South), according to their geographical location. Accounting only at the treatment criteria, the prevalence of RH was 8.2% (96/1177). RH prevalence in the southern, central and northern regions was respectively: 1, 3.8 and 3.3% (P<0.001). Participants with RH were older and showed a higher body mass index (BMI) and waist circumference compared with other subjects (P<0.005). RH risk was statistically significant (P<0.01) increased of 1.52-fold (95% confidence interval (CI):1.20-1.92) for one unit increase in s.d. score of age (11 years), and 1.50-fold (95% CI:1.22-1.83) for one unit increase in s.d. score of BMI (4.5 kg m-2). Including in RH diagnosis also the adherence to appropriate lifestyle measures, such as dietary salt restriction (Na24h <100 mmol) and normal BMI (18-25 kg m-2), RH prevalence felt respectively to 2.2% (26/1177) and 0.8% (9/1177). In conclusion in this national sample of Italian hypertensive population, among participants following both drug treatment and lifestyle modifications advises, the 'true' RH prevalence appears to be particularly low.