Association of microalbuminuria and adverse outcomes in hypertensive patients: a meta-analysis

Background Studies on the association of microalbuminuria with adverse outcomes in patients with hypertension remain controversial. This meta-analysis aimed to assess the predictive value of microalbuminuria in hypertensive patients. Methods PubMed and Embase databases were comprehensively searched for studies that published from their inceptions to July 10, 2020. Observational studies reporting the association of microalbuminuria (defined as urinary albumin excretion 30 and 300 mg/24 h urine or albumin/creatinine ratio 30–300 mg/g from a spot urine or equivalent value) with all-cause mortality or major adverse cardiovascular events (MACEs) in hypertensive patients were selected. Results Nine studies with a total of 19,893 hypertensive patients were included. When compared with those without microalbuminuria, hypertensive patients with microalbuminuria had an increased risk of all-cause mortality (risk ratio [RR] 1.68; 95% confidence interval [CI] 1.46–1.93) and MACEs (RR 1.40; 95% CI 1.22–1.62), respectively. Gender-specific analysis indicated that microalbuminuria was significantly associated with an increased risk of all-cause mortality (RR 1.61; 95% CI 1.17–2.21) in men but not in women (RR 1.18; 95% CI 0.78–1.80). Conclusion This meta-analysis suggests that microalbuminuria is independently associated with higher risk of MACEs and all-cause mortality in hypertensive patients. Determination of microalbuminuria has potential to improve the risk classification of hypertension.