Olaniran KO, Allegretti AS, Zhao SH, et al. - By performing this multicenter, observational study, researchers intended to gain insight into the trajectory as well as the predictors of kidney function decline in patients with sickle cell trait and sickle cell disease. For this purpose, they used registry data (obtained January 2005 through June 2018). Participants were adult black patients carrying sickle cell trait (n = 1,251) or disease (n = 230) (exposures) or normal hemoglobin phenotype (n = 8,729) (reference) status, with a median follow-up of 8 years. Findings revealed faster eGFR decline in relation to sickle cell trait and disease among black patients, with a faster decline in sickle cell disease. Low hemoglobin S was found to be related to faster eGFR decline in sickle cell trait but may be confounded by concurrent hemoglobinopathies.