title: Evaluating risk factors for chronic kidney disease in pediatric patients with sickle cell anemia.
abstract: Patients with sickle cell anemia (SCA) have an increased prevalence of nephropathy and mortality from chronic kidney disease (CKD).
  
  
  
  We evaluated the association of hyperuricemia and nocturnal hypertension with lower estimated glomerular filtration rate (eGFR) using cystatin-C in patients aged 10-21 years with the HbSS or HbSB0 form of the disease during a non-acute clinic visit. eGFR and uric acid measurements were obtained in 83 and 81 participants, respectively, and 24-h ambulatory blood pressure monitoring (ABPM) was performed in 44 participants. Annual testing included vital signs, complete blood count, comprehensive metabolic panel, medications, urine microalbumin/creatinine, and lactate dehydrogenase measurements. Hyperuricemia was defined as a uric acid level of ≥5.5 mg/dL. Nocturnal hypertension was defined as >25% of nocturnal readings at >95th percentile according to norms established by the American Heart Association Statement on ABPM in children and adolescents.
  
  
  
  The mean eGFR was statistically significantly lower in patients with hyperuricemia than in those with normal uric acid levels (143 vs. 161 mL/min/1.73 m2, respectively). Of the 44 participants for whom ABPM data were available, 14 (32%) had systolic nocturnal hypertension and 12 (27%) had diastolic nocturnal hypertension. The mean eGFR was statistically significantly lower in participants with nocturnal systolic and diastolic hypertension than in those with normal nocturnal blood pressure. In a regression model, nocturnal hypertension and hyperuricemia were associated with a lower eGFR.
  
  
  
  Two risk factors for CKD, i.e., nocturnal hypertension and hyperuricemia, were associated with lower eGFR in older children and adolescent patients with SCA. Long-term studies on their association with progression to CKD in this population are warranted.
  
  
  
  Nocturnal hypertension and hyperuricemia are established risk factors for nephropathy in other diseases and may play a role in SCA nephropathy.
authors.affiliation: Pediatric Hematology and Oncology, University of Alabama at Birmingham, 1600 7th Ave South, Lowder 512, Birmingham, AL, 35233, USA. jlebensburger@peds.uab.edu.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Lebensburger
authors.affiliation: Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Gary R
authors.initials: GR
authors.lastname: Cutter
authors.affiliation: Pediatric Hematology and Oncology, University of Alabama at Birmingham, 1600 7th Ave South, Lowder 512, Birmingham, AL, 35233, USA.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Howard
authors.affiliation: Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Muntner
authors.affiliation: Pediatric Nephrology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Feig
mesh_terms: D000293:Adolescent; D000328:Adult; D000755:Anemia, Sickle Cell / Q000150:complications* / Q000503:physiopathology; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D002648:Child; D015331:Cohort Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D033461:Hyperuricemia / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D007668:Kidney / Q000503:physiopathology; D008297:Male; D015995:Prevalence; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D012307:Risk Factors; D014527:Uric Acid / Q000097:blood; D055815:Young Adult
chemical_list: D014527:Uric Acid
keywords: Children; Hypertension; Hyperuricemia; Kidney; Nephropathy; Sickle cell disease