Clinical Characteristics Of Igg4-Related Disease In The United Arab Emirates: A Retrospective Single-Center Study

Background: Demographic and clinical data of IgG4-related disease affecting solely the native population of the UAE, known as Emiratis, does not exist in the literature. Aim: To explore the demographic and clinical characteristics of IgG4-related disease in a well-defined population of Emirati patients attending Cleveland Clinic Abu Dhabi, a large tertiary center in the Middle East. Patients and Methods: The data presented is part of a retrospective cohort study, in which 15 Emirati patients with IgG4-related disease (IgG4-RD) were evaluated over 5 years from April 2015 to September 2020 at the rheumatology outpatient clinic at Cleveland Clinic Abu Dhabi. The demographic and clinical data were recorded. Descriptive statistics of the variables were applied. Results: Fifteen Emirati patients with an established diagnosis of IgG4-RD were assessed. There was a male predominance (53%) with a median age at the time of diagnosis of 47 +/- 11.2 years. A 6-year lag period was noted from the initial presentation until a diagnosis of IgG4-RD was established. The most frequent comorbidities observed were hematological conditions (63%), hypertension (47%), diabetes mellitus (40%), and gastroesophageal reflux disease (40%). An elevated serum IgG4 was observed in the majority of patients at the initial presentation. Rheumatoid factor was detected in 13% and low titer of immunofluorescence antinuclear antibody in 7%. 86% of patients had a tissue biopsy with marked lymphocytic and plasmacytic infiltration being the most reported finding in 86%. Methotrexate, azathioprine, and rituximab were the most frequently prescribed disease-modifying agents. Conclusion: We report the first comprehensive analysis on a small cohort of Emirati patients with IgG4-RD. We describe disease features unique to UAE patients and demonstrate that IgG4-RD has a significant disease burden. Our results underscore the need for the IgG4-RD UAE-wide national registry to improve the quality of care of these patients.