Hydroxychloroquine Associated with Lower Glomerular Filtration Rate Decline in Lupus Nephritis.

Abstract

Background: Hydroxychloroquine (HCQ) protects kidney function in lupus nephritis (LN) by preventing flares, yet some cohort studies show no significant benefit in kidney function with HCQ. Clarifying these conflicting findings by showing early and long-term benefits of HCQ on kidney function preservation is critical. Therefore, we analyzed data from our retrospective longitudinal inception LN cohort to examine the time-varying effects of HCQ on kidney function decline in LN.

Methods: Retrospective data from an incident biopsy proven LN cohort. Creatinine values at LN diagnosis through the last follow-up were abstracted to estimate the glomerular filtration rate (eGFR). Using HCQ exposure as a time-dependent covariate, we examined associations between HCQ exposure and sustained eGFR decline ≥30% and ≥40%. We also calculated an annual eGFR slope decline by HCQ exposure using linear mixed effects analysis.

Results: Among 209 patients, 33% & 23% experienced eGFR decline ≥30% and ≥40% over time. Time-varying HCQ exposure was associated with 60% and 62% lower risk of eGFR decline of ≥30% or ≥40%, after adjusting for propensity scores. An 77% lower risk of eGFR decline was noted in patients with CKD ≥3 with HCQ. HCQ exposure reduced the annual eGFR slope decline by 5.12 and 3.17 ml/min/1.73 m² within first 5 and 10 years of diagnosis.

Conclusion: HCQ use was associated with early and long-term benefits on kidney function in LN, including those with CKD ≥3. Universal HCQ use should be encouraged in LN patients.