Hyperuricemia and the Risk of Chronic Kidney Disease Progression among Sickle Cell Anemia Patients (HbSS) in North-eastern Nigeria

Abstract

Sickle cell nephropathy is a common complication of HbSS. Several risk factors have been found to be associated with the development of progressive chronic kidney disease. Serum uric acid is usually elevated in patients with chronic kidney disease. This study evaluated the prevalence of hyperuricemia among HbSS patients and determined the association between hyperuricemia and the risk of progressive kidney disease among HbSS patients in northeastern Nigeria. The study is a single centre cross sectional study conducted in the sickle cell clinic of University of Maiduguri Teaching Hospital, northeastern Nigeria. Study participants consisted of HbSS participants sequentially recruited from January 2013 to April 2018. Socio-demographic and clinical variables were obtained from each participant. Glomerular filtration rate was calculated using the modification of diet in kidney disease (MDRD) equation and staged based on KDOQI classification. Participants with eGFR <60ml/minute/1.73m2 were considered to have chronic kidney disease. Serum uric acid was measured and levels >419mmol/L were considered elevated. Out of a total of 261 participants that were seen in the sickle cell clinic during the study period, 217 had complete data set and were included. The prevalence of hyperuricemia was 62.3% among the study population. Sixty-three (57.8%) patients with hyperuricemia had chronic kidney disease whereas 16 (19.5%) patients with normal serum uric acid levels had chronic kidney disease. ODDS ratio of chronic kidney disease in hyperuricemic patients was 2.38(95% CI 1.98 – 3.01). The mean PCV in patients with hyperuricemia and those with normal uric acid levels were 17.71 ± 4.93 and 23.26 ± 5.43 respectively (p=0.000). There were significant differences between patients with normal and elevated serum uric acid levels and serum creatinine (109.71±96.99µmol/L vs 204.11 ± 194.42µmol/L, p=0.000); urea (6.41 ± 6.72mmol/L vs 10.75 ± 6.56mmol/L, p=0.000). This study has shown that hyperuricemia is common among HbSS patients and it is associated with the development of progressive chronic kidney disease among HbSS patients.