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

Abstract

Prevalence of renal impairment is increasing with aging in sickle cell anemia (SCA) patients, and is responsible for a high morbidity and mortality. However, sickle cell nephropathy s 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 the Cox model. Five‐hundred and thirty‐five 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\u2009mm Hg HR: 2.02 [1.02–3.971], LDH (for 100\u2009IU/L increase) HR: 1.28 [1.12;1.48] and tricuspid regurgitation velocity >2.5\u2009m/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\u2009years (p <\u20090.001). 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.