Objective: To investigate the relationship between blood pressure (BP), renal haemodynamics, anthropometric measures of obesity and urinary albumin excretion in hypertension and in a control group.
Methods: Urinary albumin, BP and anthropometric measurements were carried out in patients attending the hypertension clinic of the University Hospital of the West Indies. A randomised stratified sample was then selected for renal haemodynamic assessment. A normoalbuminuric control group without hypertension or diabetes was also selected. Renal haemodynamics was assessed by measuring glomerular filtration rate using 51-chromium edetic acid (51Cr-EDTA) and renal blood flow using 125-iodohippurate (125-PAH).
Results: Urinary albumin excretion was positively and significantly correlated with systolic pressure (beta = 0.011, P < 0.003, R = 0.22), current body weight (beta = 0.014, P < 0.04, R = 0.15) and the presence of diabetes (beta = 0.9, P < 0.001, R = 0.3). In the sample selected for renal haemodynamics, patients with microalbuminuria had lower age-adjusted corrected renal blood flow (P < 0.006), effective renal plasma flow (P < 0.006) and higher filtration fraction (P < 0.006) when compared with patients without microalbuminuria. Glomerular filtration rate in patients with microalbuminuria was not different from those without. Urinary albumin excretion was positively and significantly correlated with systolic pressure (beta = 0.016, P < 0.003, R = 0.40) and inversely related to corrected renal blood flow (beta = -1.13, P < 0.0002, R = 0.46). Waist:hip ratio was inversely related to corrected renal blood flow (beta = -1.74, P < 0.02, adjusted R = 0.48).
Conclusion: Systolic BP, diabetes and body weight were significant predictors of albuminuria in our patients. Microalbuminuria and body fat distribution as assessed by waist:hip ratio were important determinants of renal haemodynamics in this population.