IMPACT OF LUPUS NEPHRITIS FLARES ON HEALTHCARE UTILIZATION: A RETROSPECTIVE COHORT STUDY IN THE UNITED STATES BETWEEN 2016 AND 2025
Author(s)
Jiying Zou, MSc1, Huong Trinh, MSc1, Jesse Sussell, PhD1, Shu Wang, MSc2, Anisha M. Patel, PhD1, William F. Pendergraft III, MD, PhD1, Lisa Lindsay, PhD, MPH1;
1Genentech Inc., South San Francisco, CA, USA, 2Genesis Research Group, Hoboken, NJ, USA
1Genentech Inc., South San Francisco, CA, USA, 2Genesis Research Group, Hoboken, NJ, USA
OBJECTIVES: This study assessed incremental healthcare utilization (HCU) due to lupus nephritis (LN) flares.
METHODS: A retrospective cohort study (2016-2025) was conducted using de-identified patient electronic health records (EHRs) from a US-based healthcare network. Adults were included in the study who had LN identified between January 1, 2018 and May 31, 2024 (index) and provided EHRs spanning 2 years pre-index; baseline (index ±90 days) urine protein-to-creatinine ratio (UPCR) of ≥0.5 g/g and any estimated glomerular filtration rate (eGFR) result; >1 additional post-baseline UPCR and eGFR result; and no prior dialysis or kidney transplant. Patients with LN flares were matched (1:1) to patients without flares using a propensity score derived from clinical and demographic characteristics. One-way crossover was allowed for patients who were flare negative but experienced subsequent flares. HCU rates, rate ratio (RR) and rate difference (RD) by flare status were estimated using negative binomial modeling.
RESULTS: Of the 1705 individuals eligible for inclusion in the study, 75% experienced an LN flare. Mean follow-up was 55 months and mean time to first flare was 13 months. Among the 1705 eligible patients, 1528 patients were included in the matched analyses (764 with flares; 764 without flares); the estimated HCU rate per person-year, RR and RD (95% confidence interval) for patients with flares versus without flares were: inpatient stay 0.99 versus 0.59, RR=1.68 (1.35, 2.09), RD=0.40 (0.23, 0.58); emergency room visits 0.93 versus 0.41, RR=2.29 (1.80, 2.91), RD=0.52 (0.36, 0.69); and outpatient visits 29.49 versus 19.92, RR=1.48 (1.35, 1.62), RD=9.57 (7.29, 11.84). All findings were significant (P<0.001).
CONCLUSIONS: LN flares significantly increased the annual rate of HCU, demonstrating the importance of sustained disease control for both patients and society.
METHODS: A retrospective cohort study (2016-2025) was conducted using de-identified patient electronic health records (EHRs) from a US-based healthcare network. Adults were included in the study who had LN identified between January 1, 2018 and May 31, 2024 (index) and provided EHRs spanning 2 years pre-index; baseline (index ±90 days) urine protein-to-creatinine ratio (UPCR) of ≥0.5 g/g and any estimated glomerular filtration rate (eGFR) result; >1 additional post-baseline UPCR and eGFR result; and no prior dialysis or kidney transplant. Patients with LN flares were matched (1:1) to patients without flares using a propensity score derived from clinical and demographic characteristics. One-way crossover was allowed for patients who were flare negative but experienced subsequent flares. HCU rates, rate ratio (RR) and rate difference (RD) by flare status were estimated using negative binomial modeling.
RESULTS: Of the 1705 individuals eligible for inclusion in the study, 75% experienced an LN flare. Mean follow-up was 55 months and mean time to first flare was 13 months. Among the 1705 eligible patients, 1528 patients were included in the matched analyses (764 with flares; 764 without flares); the estimated HCU rate per person-year, RR and RD (95% confidence interval) for patients with flares versus without flares were: inpatient stay 0.99 versus 0.59, RR=1.68 (1.35, 2.09), RD=0.40 (0.23, 0.58); emergency room visits 0.93 versus 0.41, RR=2.29 (1.80, 2.91), RD=0.52 (0.36, 0.69); and outpatient visits 29.49 versus 19.92, RR=1.48 (1.35, 1.62), RD=9.57 (7.29, 11.84). All findings were significant (P<0.001).
CONCLUSIONS: LN flares significantly increased the annual rate of HCU, demonstrating the importance of sustained disease control for both patients and society.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
EE186
Topic
Economic Evaluation
Topic Subcategory
Cost/Cost of Illness/Resource Use Studies
Disease
SDC: Systemic Disorders/Conditions (Anesthesia, Auto-Immune Disorders (n.e.c.), Hematological Disorders (non-oncologic), Pain), SDC: Urinary/Kidney Disorders