Microalbuminuria in HIV disease.

BACKGROUND/AIMS: Microalbuminuria is a marker for early kidney disease and cardiovascular risk. The purposes of this study were to determine the prevalence of microalbuminuria in an HIV-infected clinic population, to test the predictive value of a single urine albumin/creatinine ratio (ACR) to identify persistent microalbuminuria and to examine covariates of microalbuminuria. METHODS: We conducted a prospective cohort study of HIV-infected subjects (n = 182) without proteinuria (urine protein/creatinine ratio ≥0.5 g/g), elevated serum creatinine, diabetes, or chronic inflammatory conditions. Subjects completed three research visits within 9 months. Microalbuminuria was defined as the geometric mean ACR of 25-355 mg/g for females and 17-250 mg/g for males. RESULTS: The prevalence of microalbuminuria was 14%. The negative predictive value of a single urine ACR determination was 98%, whereas the positive predictive value was only 74%. Microalbuminuria was similar among Black (15%) and non-Black (14%) subjects (p = 0.8). Subjects with microalbuminuria were more likely to have hypertension (p = 0.02) and metabolic syndrome (p = 0.03). While duration of HIV infection and the level of HIV viremia were similar between groups, those with microalbuminuria were more likely to have a CD4 count <200 cells/µl (p = 0.0003). In a multivariate logistic regression analysis, the only significant independent predictors of microalbuminuria were low CD4 count (p = 0.018) and current ritonavir exposure (p = 0.04). CONCLUSION: The prevalence of microalbuminuria in an HIV-infected clinic population was similar to earlier reports, and was associated with hypertension and impaired immune function. A single normal ACR determination effectively excludes microalbuminuria, whereas an elevated ACR requires confirmation.

Hydrogen-1 MR spectroscopy for measurement and diagnosis of hepatic steatosis.

OBJECTIVE: Hydrogen-1 MR spectroscopy ((1)H-MRS) is gaining acceptance as a noninvasive technique for assessment of hepatic steatosis, and the findings have been found to correlate closely with histopathologic grade. The aims of this study were to validate (1)H-MRS performed with a 3-T MRI system for quantifying hepatic steatosis and to determine threshold values of (1)H-MRS proton density fat fraction corresponding to standard histopathologic grade in patients undergoing diagnostic liver biopsy. SUBJECTS AND METHODS: We conducted a prospective cross-sectional liver MRS study with 52 subjects undergoing diagnostic liver biopsy. The diagnostic accuracy of (1)H-MRS was evaluated with receiver operating characteristic curves. RESULTS: The diagnostic accuracy of (1)H-MRS for hepatic steatosis was high with an area under the receiver operating characteristic curve of 0.94 (95% CI, 0.88-1.0). Results were similar for three (1)H-MRS measurements obtained at different locations in the liver, for two independent pathologists, and whether fibrosis was present or absent. One third of participants had elevated transaminase concentrations of unknown cause, and (1)H-MRS estimates of steatosis had perfect agreement with histopathologic grade in this group. Calculated (1)H-MRS proton density fat fraction thresholds for histologic grades were less than 17% for grade 0 or trace steatosis, 17-38.6% for grade 1, and greater than 38.6% for grade 2 or higher. CONCLUSION: Hydrogen-1 MR spectroscopy is an effective, noninvasive technique that can be used to diagnose and quantify hepatic steatosis. Hydrogen-1 MR spectroscopy thresholds corresponded with histopathologic grades and may be useful in the workup of patients with elevated transaminase concentrations.