Risk factors for CKD stage II onset in a prospective cohort of homozygous sickle cell adults.

Prevalence of renal impairment is increasing with aging in sickle cell anemia (SCA) patients responsible for a high morbidity and mortality. However, sickle cell nephropathy natural course remains mostly unknown. We conducted a prospective observational cohort study aimed to identify risk factors for CKD stage II in a cohort of SCA patients. Baseline clinical and biological parameters were collected. Renal parameters were updated at each visit. Risk factors were analyzed using Cox model. 535 SCA patients were included with a median follow-up of 5.33 (IQR:2.10-8.13) years. Median age was 22 (IQR:19-30) years old. Glomerular hyperfiltration was detected in 299 (55.9%) patients, microalbuminuria and macroalbuminuria in 180 (34%) and 67 (12.7%) patients respectively. During follow up, CKD stage II onset was detected in 39 patients (7.3%). Risk factors for CKD stage II after adjustment on baseline eGFR and age were macroalbuminuria HR: 3.89 [95% CI: 1.61;9.43], diastolic blood pressure (DBP) above 70 mmHg HR: 2.02 [1.02-3.971], LDH (for 100 UI/L increase) HR: 1.28 [1.12;1.48] and tricuspid regurgitation velocity >2.5 m/sec HR: 2.89 [1.20- 6.99]. Multivariate analysis also found age as a strong independent risk factor with HR: (per year increase) 1.13 [1.09;1.16] and a 13.3 fold increase above 30 years (p<0.001). Our results show a high incidence of CKD stage II with aging, with a strong significant risk increase after 30 years old, and pinpoint baseline DBP, macroalbuminuria and increased LDH as independent risk factors raising the issue of optimal blood pressure targets for SCA patients. This article is protected by copyright. All rights reserved.