Introduction

IgG4-related disease (IgG4-RD) is a chronic inflammatory condition that culminates in fibrosis and organ damage. The real-world diagnosis, treatment and outcomes of IgG4-RD patients remain poorly understood.

Aims & Methods

To characterise diagnosis, clinical characteristics, treatment and disease burden, healthcare use and patient-reported outcomes (PRO) in IgG4-RD patients. Data were drawn from a real-world, cross-sectional survey of physicians and patients with IgG4-RD in Europe (France, Spain, Italy, Germany and the United Kingdom), Brazil and the Kingdom of Saudi Arabia (KSA) from September 2023 – September 2024. Physicians reported patient demographics, clinical characteristics, patient journey, treatment patterns and healthcare resource use. Patients self-reported on burden of fatigue using the FACIT-Fatigue Scale, and work and activity impairment using the WPAI questionnaire (Table 1). Analyses were descriptive.

Results

Data were reported by 208 physicians on 982 patients (France: n=181, Spain: n=96, Italy: n=160, Germany: n=162, UK: n=143, Brazil: n=89, KSA: n=151), of whom 254 provided self-reported data. Mean (standard deviation; SD) patient age was 53.8 (13.4) years (59.6% Male; 73.7% White). Overall, mean (SD) age at symptom onset was 49.6 (13.0) years. Time from symptom onset to diagnosis was 8.9 (19.5) months, ranging from 3.3 (8.1) in KSA and 21.0 (30.0) in Brazil. Fatigue (57.0%), weight loss (32.3%), and joint pain (24.1%) were the most common symptoms at first consultation; the most common organ manifestations being pancreas (41.9%), bile ducts (25.2%) and abdominal/pelvic lymph nodes (23.9%). Primary care physicians (46.3%) and gastroenterologists (17.4%) were most often consulted first about symptoms, with gastroenterologists (37%) and rheumatologists (31%) most often confirming IgG4-RD diagnosis. Most patients were treated by gastroenterologists (53.9%), rheumatologists (46.8%) and primary care physicians (20.4%). Patients required a mean (SD) of 5.1 (4.0) consultations and 17.4 (8.9) tests prior to diagnosis; physical examination (85.7%), serum IgG4 levels (84.5%), and tissue biopsy (81.0%) were most frequently used to aid diagnosis. 86.0% of patients had another condition suspected prior; most commonly pancreatitis (28.3%), cholangiocarcinoma (14.1%) and Sjögren’s syndrome (12.5%). Post-diagnosis, mean (SD) time to treatment initiation was 16.5 (28.0) months, ranging from 12.0 (22.5) in Europe to 34.6 (38.2) in KSA. Prednisone was the most common first line therapy (78.6%), followed by rituximab (12.7%) and azathioprine (9.7%). In the 12 months prior to survey, 26.7% of patients were hospitalised (21.4% in Europe; 15.4% in Brazil and 56.0% in KSA). Of those hospitalised, the mean (SD) number of hospitalisations was 1.4 (0.8), ranging from 1.2 (0.5) in KSA to 1.5 (0.9) in Brazil. 41.6% of patients were admitted via the emergency room (ER) and spent 5.9 (5.0) nights in hospital.

Conclusion

The diagnostic journey for IgG4-RD patients is often delayed, involving multiple consultations, tests and misdiagnoses. Despite the heterogeneous nature of the disease, most patients reported substantial burden of illness and impact to daily lives. Optimizing diagnosis and treatment pathways may improve disease burden and quality of life among patients with IgG4-RD.

Disclosure

ED has received consulting fees from Amgen Inc.
EC has received consulting fees from Advance/Intercept, Amgen, Dr Falk Pharma, GSK, Ipsen, Mirum, Moderna, Sail, Sanofi, and Zenus and a research grant from Janssen.
JP, RW, AM and MR are Amgen employees and own Amgen stock.
SLB and HS are employees of Adelphi Real World