Leoné Malan, Nicolaas T. Malan, Wayne Smith, Hugo W. Huisman, Catharina M. C. Mels, A. Kruger, Minrie Greeff, Ruan Kruger, C.M.T. Fourie, J.M. Van Rooyen, Rudolph Schutte, and Aletta E. Schutte
Twenty-four hour urinary albumin excretion reflects general endothelial damage, relates to arterial stiffness, and predicts adverse health outcomes. Albumin determined from easily collected spot urine samples is also predictive. No prognostic evidence for albumin excretion from any means of urine collection exists for Africans. We followed health outcomes in 1061 randomly selected non-diabetic, HIV negative Africans (mean age: 51.5 years; 62.0% women). We determined the baseline urinary albumin-to-creatinine ratio from spot urine samples. Over a median follow-up of 4.52 years, 132 deaths occurred of which 47 were cardiovascular-related. The urinary albumin-to-creatinine ratio averaged 0.68 (5th to 95th percentile interval; 0.13, 4.54 mg/mmol). In multivariable-adjusted analyses, albumin excretion predicted all-cause mortality (hazard ratio, 1.26; 95% confidence interval, 1.07, 1.48; P=0.006), and a tendency existed for cardiovascular (1.26; 0.97, 1.63; P=0.087) mortality, which seemed driven by stroke (1.72; 1.17, 2.54; P=0.006) and not cardiac mortality (0.67; 0.41, 1.07; P=0.094). The predictive value remained in 528 hypertensives for both all-cause (1.38; 1.13, 1.69; P=0.001) and cardiovascular mortality (1.45; 1.07, 1.96; P=0.017), but again driven by stroke. Our findings remained significant after excluding participants with macroalbuminuria and those on anti-hypertensive treatment. In conclusion, in non-diabetic HIV-negative Africans, albumin excretion from spot urine samples predicts all-cause and stroke mortality.