Urinary Albumin Excretion at Follow-Up Predicts Cardiovascular Outcomes in Subjects With Resistant Hypertension

BACKGROUND Renal function and albuminuria predict cardiovascular disease (CVD) in general population. However, their prognostic value in patients with resistant hypertension (RH) is somewhat unknown. OBJECTIVE To determine the ability of renal function and albuminuria to predict CVD in RH patients. METHODS One hundred and thirty-three RH (blood pressure [BP] ≥140/90mmHg despite treatment with ≥3 drugs) patients were evaluated. Median follow-up was 73 months. Primary endpoint was a composite of non-fatal cardiovascular events or cardiovascular death. Serum creatinine (SCr) and estimated glomerular filtration rate (eGFR) were determined. Microalbuminuria was defined as a urinary albumin-to-creatinine ratio (UACR) ≥30mg/g. RESULTS Twenty-two patients (16.5%) reached the primary endpoint. Long-term elevated UACR (66 vs. 17mg/g, P=0.045), but not at baseline, was associated with the primary endpoint, after adjusting for age, prior CVD, and both eGFR and office systolic-BP at baseline and during follow-up. Although baseline SCr and eGFR were associated with CVD, significance was lost after baseline risk adjustment. Baseline microalbuminuria prevalence was 45% and 41% in patients with and without CVD (P=0.813), while percentages of patients with microalbuminuria at follow-up were 67% and 28%, respectively (P=0.002). More patients with de novo CVD, compared with those without CVD, developed microalbuminuria at follow-up (28% vs. 6%) or had persistent microalbuminuria (39% vs. 21%), while fewer patients with CVD had microalbuminuria regression (11% vs. 19%) or remained normoalbuminurics (22% vs. 53%; overall P=0.005). CONCLUSION In RH patients, the inability to microalbuminuria regression, either due to persistence or new appearance, independently predicts CVD.