FLARE FREQUENCY, ORGAN DAMAGE, AND ECONOMIC BURDEN AMONG INDIVIDUALS WITH IMMUNOGLOBULIN G4-RELATED DISEASE (IGG4-RD) IN THE UNITED STATES
Author(s)
Sushmitha Inguva, PhD1, Emma L. Culver, BSc (Hons), MBChB, MRCP, DPhil2, Matthew C. Baker, MD, MS3, Pallavi Rane, PhD1, Laura C. Moore-Schiltz, PhD4, Melissa Rosen, MD1, Kristina Patterson, MD, PhD1, Donna McMorrow, BS4, Zulkarnain Pulungan, PhD4, John H. Stone, MD, MPH5;
1Amgen Inc., Thousand Oaks, CA, USA, 2Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom, 3Stanford University, Palo Alto, CA, USA, 4Inovalon, Bowie, MD, USA, 5Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
1Amgen Inc., Thousand Oaks, CA, USA, 2Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom, 3Stanford University, Palo Alto, CA, USA, 4Inovalon, Bowie, MD, USA, 5Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
OBJECTIVES: To describe healthcare resource utilization (HCRU), costs, and indicators of organ damage by flare frequency in individuals with immunoglobulin G4-related disease (IgG4-RD) using US administrative claims data.
METHODS: Adults with IgG4-RD were identified using a validated patient case-finding algorithm in Medicare fee-for-service (2018 to 2022) and Inovalon MORE2 registry (2018 to June 2023). The index date was the first claim for an algorithm-defined IgG4-RD ICD-10 code. Socio-demographics and baseline disease characteristics in the 12-month pre-index period were assessed. Flares, HCRU, costs, and organ damage were evaluated in the ≥12-month post-index period. Flares were defined based on treatment escalation as initiation of IgG4-RD therapy, addition of glucocorticoids (GC) to existing non-GC therapy, or GC dose escalation by ≥5mg following a clinical visit, as well as ureteral stent or endoscopy and biliary stent procedures. Organ damage was identified as incident claims for clinically informed organ-specific indicators and analyzed as any damage and by specific indicators.
RESULTS: A total of 965 patients were identified (mean age 65.7±14.2 years; 59.2% male; 61.5% white; mean follow-up 45.3±19.5 months). Patients were categorized by flare frequency: 0 (n=92, 9.5%), 1 (n=156, 16.2%), 2 (n=149, 15.4%), and ≥3 flares (n=568, 58.9%). The median (IQR) annualized flare rate was 0.95 (1.24). Hospitalizations occurred in 22.8%, 31.4%, 34.2%, and 44.5%; emergency visits in 35.9%, 40.4%, 32.9%, and 44.2%; and specialist visits in 68.5%, 82.1%, 75.8%, and 87.1% of patients across the 0, 1, 2, and ≥3 flare groups, respectively. Median (IQR) per-patient-per-year total healthcare costs were $17,423 ($26,004), $28,433 ($34,632), $28,572 ($39,272), and $37,957 ($46,447) across the flare groups. Organ damage occurred in 35.9%, 37.2%, 37.6%, and 55.5% of patients across the flare groups.
CONCLUSIONS: Increasing flare frequency in IgG4-RD was associated with higher HCRU, healthcare costs, and organ damage, highlighting the need for therapies that effectively reduce flares and long-term disease burden.
METHODS: Adults with IgG4-RD were identified using a validated patient case-finding algorithm in Medicare fee-for-service (2018 to 2022) and Inovalon MORE2 registry (2018 to June 2023). The index date was the first claim for an algorithm-defined IgG4-RD ICD-10 code. Socio-demographics and baseline disease characteristics in the 12-month pre-index period were assessed. Flares, HCRU, costs, and organ damage were evaluated in the ≥12-month post-index period. Flares were defined based on treatment escalation as initiation of IgG4-RD therapy, addition of glucocorticoids (GC) to existing non-GC therapy, or GC dose escalation by ≥5mg following a clinical visit, as well as ureteral stent or endoscopy and biliary stent procedures. Organ damage was identified as incident claims for clinically informed organ-specific indicators and analyzed as any damage and by specific indicators.
RESULTS: A total of 965 patients were identified (mean age 65.7±14.2 years; 59.2% male; 61.5% white; mean follow-up 45.3±19.5 months). Patients were categorized by flare frequency: 0 (n=92, 9.5%), 1 (n=156, 16.2%), 2 (n=149, 15.4%), and ≥3 flares (n=568, 58.9%). The median (IQR) annualized flare rate was 0.95 (1.24). Hospitalizations occurred in 22.8%, 31.4%, 34.2%, and 44.5%; emergency visits in 35.9%, 40.4%, 32.9%, and 44.2%; and specialist visits in 68.5%, 82.1%, 75.8%, and 87.1% of patients across the 0, 1, 2, and ≥3 flare groups, respectively. Median (IQR) per-patient-per-year total healthcare costs were $17,423 ($26,004), $28,433 ($34,632), $28,572 ($39,272), and $37,957 ($46,447) across the flare groups. Organ damage occurred in 35.9%, 37.2%, 37.6%, and 55.5% of patients across the flare groups.
CONCLUSIONS: Increasing flare frequency in IgG4-RD was associated with higher HCRU, healthcare costs, and organ damage, highlighting the need for therapies that effectively reduce flares and long-term disease burden.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
CO194
Topic
Clinical Outcomes
Topic Subcategory
Relating Intermediate to Long-term Outcomes
Disease
SDC: Rare & Orphan Diseases, SDC: Systemic Disorders/Conditions (Anesthesia, Auto-Immune Disorders (n.e.c.), Hematological Disorders (non-oncologic), Pain)