Predictors of renal function progression in adults with homozygous sickle cell disease

Longitudinal studies of renal function may improve understanding of the pathophysiological mechanisms underlying sickle cell disease (SCD) nephropathy and may identify possible biological and clinical markers of renal function determined over time. Data from the Jamaica Sickle Cell Cohort Study (JSCCS) were extracted and the glomerular filtration rate (GFR) was estimated using the Chronic Kidney Disease Epidemiological and the SCD specific JSCCS-GFR equations from all adulthood serum creatinine measurements in homozygous SS patients. The other dataset consisted of measured GFR at two times about 13 years apart. Linear mixed model (LMM) regression analyses were conducted to determine predictors of GFR and serum creatinine over time. 191 individuals with SS disease had 867 GFR estimates available. Serum creatinine significantly increased from baseline whereas estimated GFR showed a significant decline. Serum creatinine showed positive association with increasing age, male gender, body mass index and sodium levels. Haemoglobin was a significant negative predictor of estimated GFR in age- and gender-adjusted models. A total of 24 females and 17 males had repeat measurements of their GFR. The mean annual decline in GFR was -3·2 ± 2·83 ml/min/1·73 m(2) . Haemoglobin was a significant positive predictor whereas serum creatinine, systolic blood pressure and urinary albumin: creatinine ratio were negative predictors of GFR.