Disease activity of rheumatoid arthritis and kidney function decline: a large prospective registry study
Introduction Chronic kidney disease (CKD) is a common comorbidity of rheumatoid arthritis (RA). The association of longitudinal RA disease activity with long-term kidney function has remained uncertain. Method We analysed a multicentre prospective RA registry in the USA from 2001 to 2022. The exposure was updated time-averaged Clinical Disease Activity Index (TA-CDAI) categories from study enrolment. The primary outcome was a longitudinal estimated glomerular filtration rate (eGFR) change. Secondary outcomes included developments of CKD stage G3a (eGFR<60 mL/min/1.73 m2) and stage G3b (eGFR<45 mL/min/1.73 m2). Results were adjusted for relevant time-fixed and time-varying covariates. Results 31 129 patients (median age: 58.0 years, female: 76.3%, median eGFR: 90.7 mL/min/1.73 m2) contributed 234 973 visits and 146 778 person-years of follow-up. Multivariable mixed-effect linear model showed an average annual eGFR decline during follow-up in the TA-CDAI-remission group of −0.83 mL/min/1
