Prognostic value of the modified National Institute of health activity and chronicity scoring system in predicting end-stage kidney disease in Latin American lupus nephritis patients

Objective To assess the effectiveness of the modified National Institute of Health (mNIH) activity and chronicity scoring system in predicting the progression to end-stage kidney disease (ESKD) in Latin American lupus nephritis (LN) patients. Methods We retrospectively analyzed 412 patients with biopsy-proven LN. ESKD was defined as an estimated glomerular filtration rate (eGFR) < 15 mL/min/1.73 m2 for >= 3 months, dialysis for >3 months, or kidney transplant. Univariable and multivariable Cox proportional hazards regression analyses were performed to evaluate the predictive value of the mNIH activity and chronicity indices for ESKD. Results 84 patients (20.4%) progressed to ESKD at a median of 3.0 months after biopsy. The mNIH activity and chronicity indices were significantly higher in patients who progressed to ESKD compared to those who did not [7 (5-10) versus 4 (1-7), p < .001; and 3 (1-5) versus 0 (0-2), p < .001, respectively]. Multivariable Cox regression analysis revealed that the mNIH activity index (HR 1.17, 95% CI 1.05-1.29), and the mNIH chronicity index (HR 1.21, 95% CI 1.05-1.40) were independently associated with a higher risk of ESKD, adjusting for age, sex, ethnicity, and eGFR. Furthermore, fibrinoid necrosis (HR 4.09, 95% CI 1.54-10.86) and fibrous crescents (HR 2.36; 95% CI 1.06-5.27), components of the activity and chronicity indices, respectively, were also associated with a shorter time to ESKD. Conclusions In Latin American LN patients, the mNIH activity and chronicity indices are associated with an increased risk of ESKD. Among the components of these indices, shorter time to ESKD was mainly driven by fibrinoid necrosis and fibrous crescents.