Resistant hypertension prevalence and associated cardiovascular risk factors and renal disease: the I-DEMAND study

Background: Resistant hypertension (RH) is defined by most guidelines as blood pressure that remains above goal despite use of at least 3 antihypertensive agents of different classes, including a diuretic, prescribed at optimal doses. Few data are available on the clinical characteristics and on the prevalence of different forms of organ damage in these patients. Aim of this analysis is to evaluate the prevalence of RH and the prevalence of associated chronic kidney disease (CKD) and cardiovascular risk factors and diseases, participating to the Italy Developing Education and awareness on MicroAlbuminuria in patients with hyperteNsive Disease (I-DEMAND). Methods: This is an observational, cross-sectional, multicenter study aimed at determining prevalence and correlates of among Italian hypertensive patients attending out-patient referral clinics. CKD was defined as glomerular filtration rate (GFR) less than 60 ml/min per 1.73 m (Modification of Diet in Renal Disease equation) or urine albumin to creatinine ratio of at least 2.5 mg/mmol in men and of at least 3.5 mg/mmol in women or both. Results: A total of 3,754 study treated patients with renal data available were considered for this analysis: 47% women, mean age was 62±11 years and 38% had diabetes mellitus. Resistant hypertension was observed in 271 patients (7.1%). Patients with RH were older (mean age 67±9 vs 61±11 yrs, p<0.01), had higher glucose values (129±41 vs 117±39 mg/dl, p<0.001), BMI (29±45 vs 28.5±5 mg/dl, p<0.005) and triglycerides (169±107 vs 145±94 mg/dl, p<0.001). Estimated glomerular filtration rate (MDRD) was lower in RH (59±23 mL/min/1,73 m2 vs 74±24, p