Factors Affecting Glomerular Filtration Rate, as Measured by Iohexol Disappearance, in Men with or at Risk for HIV Infection

Abstract

ObjectiveFormulae used to estimate glomerular filtration rate (GFR) underestimate higher GFRs and have not been well-studied in HIV-infected (HIV(+)) people; we evaluated the relationships of HIV infection and known or potential risk factors for kidney disease with directly measured GFR and the presence of chronic kidney disease (CKD).DesignCross-sectional measurement of iohexol-based GFR (iGFR) in HIV(+) men (n = 455) receiving antiretroviral therapy, and HIV-uninfected (HIV(−)) men (n = 258) in the Multicenter AIDS Cohort Study.MethodsiGFR was calculated from disappearance of infused iohexol from plasma. Determinants of GFR and the presence of CKD were compared using iGFR and GFR estimated by the CKD-Epi equation (eGFR).ResultsMedian iGFR was higher among HIV(+) than HIV(−) men (109 vs. 106 ml/min/1.73 m2, respectively, p = .046), and was 7 ml/min higher than median eGFR. Mean iGFR was lower in men who were older, had chronic hepatitis C virus (HCV) infection, or had a history of AIDS. Low iGFR (≤90 ml/min/1.73 m2) was associated with these factors and with black race. Other than age, factors associated with low iGFR were not observed with low eGFR. CKD was more common in HIV(+) than HIV(−) men; predictors of CKD were similar using iGFR and eGFR.ConclusionsiGFR was higher than eGFR in this population of HIV-infected and -uninfected men who have sex with men. Presence of CKD was predicted equally well by iGFR and eGFR, but associations of chronic HCV infection and history of clinically-defined AIDS with mildly decreased GFR were seen only with iGFR.

Factors associated with iohexol-based glomerular filtration rate slope over 36 months in HIV-negative and HIV-positive individuals

“…Additionally, a recent study from a North American consortium of HIV cohorts reported that the incidence of end-stage renal disease (ESRD) among HIV-positive subjects that maintained durable viral suppression was similar to age-, sex-, and race-matched ESRD rates in the general population [12]. In contrast, we found no association between current CD4 count and baseline iGFR or iGFR slope, consistent with a prior report [6]. Together, these findings suggest that uncontrolled HIV infection is associated with loss of kidney function and that durable viral suppression can normalize longitudinal GFR trajectory.…”

“…To date, several groups have presented cross-sectional analyses of exogenously measured GFR in HIV-positive participants [3–6], however, few data are available regarding longitudinal GFR measures using a gold-standard method. Using GFR measurements based on iohexol plasma disappearance (iGFR), our objectives were to 1) compare longitudinal iGFR trajectories in HIV-positive and HIV-negative participants, and 2) assess the associations of baseline factors with baseline iGFR and iGFR slope in HIV-positive subjects.…”

Update on Estimation of Kidney Function in Diabetic Kidney Disease

“…The relative simplicity of the DBS method and better results compared to eGFR suggest that this or similar methodology may improve upon current practices used to assess GFR, which are either not feasible or effective in ascertaining early renal function loss clinically. Adapting this methodology to an outpatient setting by measuring iohexol clearance, as was also recently reported in a Kenyan population [106], to assess GFR in youth with type 1 diabetes requires further study to determine if it addresses the current need to better screen for early diabetic kidney disease. Given the current variability with estimation of GFR at levels >60 mL/min/1.73 m 2 , which encompasses the majority of patients with diabetes, particularly adolescents and young adults, better methods are required to fulfill the promise of reducing diabetic nephropathy by annual GFR screening in people with diabetes.…”

The Problem of Renal Function Monitoring in Patients Treated With the Novel Antiretroviral Drugs

“…1,2 The increase in life expectancy that followed the introduction of combination antiretroviral therapy (cART) induced the emergence of common chronic conditions, such as diabetes and hypertension, that act as major pathogenic determinants for the development of CKD. 2,3 Moreover, chronic infl ammation caused by the infection and probably direct renal damage mediated by viral products on kidney biology are contributory factors for the onset of CKD in these subjects. Finally, the potential toxic effect of some antiretroviral agents, such as indinavir or tenofovir (TDF), is well known with a body of evidence.…”