Background Lupus nephritis (LN) leads to end stage kidney disease (ESKD) in 17–33% after 10 years. The prevalence of chronic kidney disease stage IV (eGFR=15–29ml/min/1.73m2) is not known. Our objective was to determine the impact of time to remission and number of flares on the development of advanced CKD in LN.
Methods Patients with LN were retrieved from the Toronto Lupus Clinic database. Individuals with advanced CKD at baseline were excluded. All patients were followed for ≥ 5 years. Primary outcome: advanced CKD (eGFR&x2266;29ml/min/1.73m2). Remission: proteinuria<0.5g/24h, no active urinary sediment, serum creatinine ≤120% baseline. Flare: proteinuria >0.5g/day after remission. Death was treated as competing risk in survival analysis.
Results Of 418 eligible patients, 50% achieved remission within the first year, 24.4% within the 2nd/3rd years, 16.7% after 3 years and 8.9% never achieved remission. Sixty-six patients (15.8%) developed advanced CKD after 9.5 years on average (29 with CKD IV, 37 with ESKD). At baseline, these patients had a higher SLICC/Damage Index, lower eGFR, higher prevalence of hypertension, more proliferative nephritis and more often treated with angiotensin converting enzyme inhibitors or receptor blockers. Other variables did not differ significantly. Remission rates, flares and exposure to immunosuppressives after remission shown in table 1.
Patients who achieved remission within one year from diagnosis demonstrated significantly better outcomes compared to all other groups (p <0.0001, figure 1). Patients with complete remission between 1–3 years had similar outcomes for the first 10 years and deteriorated during the second decade of follow-up.
Conclusions Complete remission within the 1st year from LN diagnosis strongly protects against the development of advanced CKD. Flares significantly affect prognosis. Longer time on immunosuppressives after remission is associated with decreased risk for advanced CKD. These findings emphasize the importance of achieving early remission as well as flare prevention with immunosuppressives to maximize renal survival.
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