After centrifugation, serum or plasma was separated and transferred to cryotubes in aliquots of 1 ml and stored at -80☌. One ml of whole blood from EDTA blood collection tube was transferred to small tubes and CD4+ T cells were enumerated using the Facscount (Becton-Dickinson, New Jersey, USA). The study laboratory personnel collected 10 ml of fasting venous blood in an EDTA tube, and 10 ml in a plain tube. Body composition in HIV negative adults was measured with air displacement plethysmography (BodPod, USA). Lean body mass was calculated based on an assumed hydration factor of 73.2%. Total body water was calculated from post-dose deuterium enrichment with adjustment for pre-dose enrichment, using a factor of 1.041 to adjust for proton exchange. Saliva enrichment of deuterium was determined by Fourier Transform Infrared Spectrometer (IRAffinity-1, Shimadzu, Kyoto, Japan). Post-dose saliva samples were collected after four hours’ equilibration. A 30 g deuterium oxide (99.8% 2H, Sercon, Crewe, UK) weighed with 0.01 g precision was given orally after collection of pre-dose saliva samples.
Body composition in HIV positive adults was assessed using the deuterium dilution method. Weight and height were measured with calibrated scales and stadiometers, respectively, with the participant barefoot and wearing minimal clothing and body mass index (BMI) was calculated as weight (kg)/height (m) 2. Therefore, the aim of the present study was to compare serum creatinine and estimated glomerular filtration rate (eGFR) in HIV positive and negative adults and also to compare eGFR equations with 24-hour creatinine clearance in HIV positive adults. Besides, there are limited studies that have validated GFR estimating equations in HIV positive adults in Africa. However, few studies compared the renal function of ART naïve HIV positive adults with HIV negative adults. Previous studies in Africa have shown variable burden of renal disease in HIV patients. HIV patients in many developing countries are often initiated on ART without baseline GFR determination, as serum creatinine measurement tools are not easily accessible. These equations uses different variables as serum pool of creatinine can be affected by multiple factors like age, muscle mass and diet. Cockcroft and Gault (CG), the Modification of Diet in Renal Disease (MDRD), and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), have proposed GFR estimating equations that are widely used in clinical practice. To overcome this problem, several serum creatinine-based GFR estimating equations have been developed in the past. However, these GFR determination procedures are either costly or require 24-hour urine collection and therefore not commonly used in routine clinical practice. 24-hour creatinine clearance also provides a good estimate of GFR, especially in patients with low lean body mass. Precise assessment of GFR is performed using 125I-iothalamate or 51Cr-EDTA measurements.
Kidney function is assessed by determination of glomerular filtration rate (GFR). Moreover, HIV patients can develop renal impairment due to long-term exposure to antiretroviral treatment (ART) or comorbid illnesses. HIV infection directly or indirectly affects the kidneys and result in HIV-associated nephropathy (HIVAN), immune complex kidney disease and thrombotic microangiopathy.