Associations of renal vascular resistance with albuminuria in adolescents and young adults

Background. Renal vascular resistance [resistive index (RI)] has been associated with albuminuria in patients with type 2 diabetes. We studied the correlations between renal artery RI and urinary albumin excretion in adolescents and young adults. Methods. From May 2006 through September 2008, we established a cohort of adolescents and young adults based on previous history of elevated blood pressure (EBP) or normal blood pressure in childhood. This cohort was selected from the 1992-2000 nationwide mass urine screening of school children aged 6-18 years in Taiwan. From October through December 2008, we called back these adolescents and young adults living in Taipei to participate in a renal vascular stiffness study. Linear mixed regression models were applied to study the correlation between renal artery RI and urinary albumin excretion after controlling for cardiovascular (CV) risk factors. Results. Of the 147 subjects enrolled in this study, 67 had macroalbuminuria, 36 had microalbuminuria and 44 had normoalbuminuria. Except for high-density lipoprotein cholesterol, most CV risk factors did not differ significantly among these three groups. Mean RI were similar for the three groups. Neither log (urinary albumin concentration) nor log (urinary albumin: creatinine ratio) correlated with RI. Step-wise linear mixed regression models showed that RI was significantly associated only with male gender and diastolic blood pressure, but not with urinary albumin excretion or EBP in childhood. Conclusion. Renal artery RI is not associated with urinary albumin excretion in nondiabetic adolescents and young adults.