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.