Amplified association between blood pressure and albuminuria in overweight patients with biopsy-proven hypertensive nephrosclerosis

BACKGROUND An overweight person is at high risk for hypertensive renal damage. The effect of weight on the association between systolic blood pressure (SBP) and albuminuria remains unknown in patients with histologically diagnosed hypertensive nephrosclerosis. METHODS A total of 97 patients with biopsy-confirmed hypertensive nephrosclerosis were recruited from 13 centers throughout Japan. We examined the relationship between SBP and proteinuria among those who were overweight, which is defined as a body mass index ≥25 kg/m², and those who were not. We examined the interaction of weight and SBP with albuminuria at baseline and with the changes in estimated glomerular filtration rate (eGFR) during the observational period. RESULTS Our results included mean age (54 years old), blood pressure (138/80), eGFR (53 ml/min/1.73 m²), and urine albumin levels (0.2 g/day). SBP was significantly correlated with log-transformed urine albumin levels (r = 0.4, P = 0.01) in patients who were overweight (n = 38) compared with patients who were not overweight (n = 59). Multiple regression analysis revealed that the interaction between being overweight and SBP with respect to albuminuria was significantly correlated with the log-transformed urine albumin level (β = 0.39, P = 0.047) and was independent of age, sex, and potential confounding factors. The interaction between weight and SBP ≥140 mm Hg was significantly associated with a greater decrease in eGFR in the following 3 years. CONCLUSIONS Being overweight may enhance susceptibility to hypertensive glomerular damage and may eventually lead to renal progression in patients with hypertensive nephrosclerosis.