Evaluating red cell distribution width and kidney dysfunction in HIV-positive and HIV-negative adults with diabetes: insights from KwaZulu-Natal, South Africa

Background: Red cell distribution width (RDW) is a prognostic marker in cardiovascular and kidney disease, but its significance in African populations with high burdens of diabetes and HIV is unclear.Methods: 135 adults attending a diabetes clinic in South Africa were retrospectively analysed. Kidney dysfunction was defined as eGFR < 60 ml/min/1.73 m2 or abnormal proteinuria defined as urine protein:creatinine ratio (uPCR) > 0.015 g/mmol or dipstick ≥ 1+ when uPCR was missing. Associations between RDW and kidney dysfunction were assessed using correlation tests and multivariable logistic regression in this cross-sectional analysis.Results: Kidney dysfunction was present in 90/135 patients (66.7%): 29 by eGFR < 60 alone, 28 by abnormal proteinuria alone, and 33 by both. RDW did not differ significantly between those with and without kidney dysfunction (13.6 ± 1.7% vs. 13.2 ± 1.6%, p = 0.19). RDW was not correlated with eGFR (ρ = –0.10, p = 0.26) or uPCR (ρ = –0.04, p = 0.68) and showed only a weak trend with HbA1c (ρ = –0.15, p = 0.08). In multivariable regression, age (OR 1.10 per year, 95% CI 1.04–1.17, p = 0.001), and HIV-positive status (OR 4.36, 95% CI 1.06–17.98, p = 0.042) were independently associated with kidney dysfunction. RDW was not predictive (OR 1.23, 95% CI 0.90–1.67, p = 0.19).Conclusion: RDW was not independently associated with kidney dysfunction in this cohort. Age and HIV infection remained independently associated with kidney dysfunction. Proteinuria was incorporated into the composite outcome definition and therefore was not treated as an independent predictor.