Abstract
OBJECTIVE: To characterize the longitudinal trajectory of estimated glomerular filtration rate (eGFR) in patients with systemic lupus erythematosus (SLE) and identify predictors of the change in eGFR trajectory. METHODS: The longitudinal eGFR levels of patients in the Hopkins Lupus Cohort were modelled by piecewise linear regression to evaluate the slope of different line segments. The slopes were classified into declining (≤-4 mL/min/1.73 m(2) per year), stable (-4 to 4 mL/min/1.73 m(2) per year), and increasing (≥4 mL/min/1.73 m(2) per year) states. The transition rate between states and the impact of clinical parameters were estimated by a Markov model. RESULTS: The analysis was based on 494 SLE patients. At a mean follow-up of 8.8 years, 347 (70.2%), 107 (21.7%), 33 (6.7%), and 7 (1.4%) patients had zero, one, two, and three state transitions, respectively. In patients with no transition, 37 (10.7%), 308 (88.8%), and 2 (0.6%) were in declining, stable, and increasing state, respectively. In patients with one transition, 43 (40.2%) changed from declining to stable state while 29 (27.1%) changed from stable to declining state. When patients were in a non-declining GFR state, those who were younger and African Americans were more likely to transition to a declining GFR state. In adjusted analyses, high blood pressure, C4 and low hematocrit were associated with change from non-declining to declining state. High urine protein-to-creatinine ratio also tended to be associated with change from non-declining to declining state. African American patients were less likely to move from declining to non-declining state. Use of prednisone was associated with change from declining to non-declining state. CONCLUSIONS: Patients with high blood pressure, low complement C4, low haematocrit, and high urine protein-to-creatinine ratio are more likely to have a declining eGFR trajectory, while the use of prednisone stabilizes the declining eGFR trajectory.