Background/Purpose: The durability of renal remission might be a predictor of good long-term renal outcome and survival in patients with lupus nephritis (LN). We aimed to examine the predictors of long-term outcomes in patients with LN who achieve sustained complete remission.

Methods: We reviewed patients with active LN at a single center Lupus Clinic in which patients had been followed prospectively between 1970 and December 2015. We identified the patients who had a minimum of 5 years of follow-up after the complete renal remission (CR) (defined as proteinuria < 500 mg/24 hours or urine protein creatinine ratio < 0.5 and inactive urine sediment). We compared the outcomes of patients who achieved sustained CR, for a minimum of 5 years (group A) with those less than 5 years (group B). The outcomes were mortality, damage (measured by the SLICC/ACR damage index (SDI)), renal flare (any presence of cast, proteinuria, pyuria or hematuria after CR), end stage renal disease (dialysis or transplant) (ESRD) or estimated glomerular filtration rate (eGFR) < 50 mL/min, doubling of serum creatinine, and infection during 20 years after CR. Cox proportional regression models were constructed to identify the predictors of the outcomes in multivariate models controlling for gender, age, disease duration, ethnicity, hypertension and treatment for each outcomes.  

Results: A total of 345 patients were identified, 132 patients in group A and 213 patients in group B.  Most of patients were female (85%). Mean age at the diagnosis of LN was 33.94±12.85 years in group A and 31.75±11.41 years in group B. The duration between active LN and CR was 1.04±1.53 years in group A and 1.46±1.88 years in group B (P=0.03). The duration of CR in group A was 11.76 ± 7.34 years but only 1.24 ± 1.24 years in group B (P< 0.001). Death, increasing of renal SDI, renal flare, renal transplantation, ESRD or eGFR < 50 mL/min, and doubling of serum creatinine in group A were significantly lower than group B (Table 1).  Multivariate analysis revealed that group A were at a lower risk of death (hazard ratio (HR)=0.20; 95% confidence interval (CI), 0.07-0.61; P=0.004), increasing of renal SDI (HR= 0.41; 95% CI, 0.21-0.76; P=0.01), developing ESRD or eGFR < 50 mL/min (HR= 0.27; 95% CI, 0.12-0.61; P=0.001), and doubling of serum creatinine (HR= 0.29; 95% CI, 0.14-0.61; P=0.001) compared with group B.

Conclusion: Sustained complete remission for at least 5 years is an independent predictor of better prognosis in lupus nephritis in terms of reduced mortality, chronic kidney disease and end stage renal disease. Table 1 Outcomes over 20 years after complete renal remission in lupus nephritis

Group A=patients who achieved sustained complete remission, a minimum of 5 years; Group B= patients who achieved sustained complete remission, less than 5 years; SDI= SLICC/ACR damage index; ESRD= end stage renal disease; eGFR=estimated glomerular filtration rate.