Background/Purpose: In IgG4-related disease (IgG4-RD), spontaneous, or at least temporary, remissions without treatment have been reported, and watchful waiting may be appropriate in certain patients with asymptomatic and inactive disease. However, the outcomes of patients with IgG4-RD who do not undergo treatment are still unclear. This study aimed to clarify the outcomes of untreated patients with IgG4-RD and the factors related to the outcomes.

Methods: We retrospectively evaluated clinical features including laboratory data and involved organs at diagnosis in 107 patients (pts) with IgG4-RD, who were followed up for more than 6 months, at a single center in Japan. Among them, 27 patients were followed up without treatment after the initial diagnosis. We compared the clinical features of these 27 patients with those of the 80 patients who underwent treatment. The outcomes of untreated patients were investigated, and logistic regression analysis was performed to assess factors related to the outcomes. Deterioration of IgG4-RD was defined as symptomatic, radiological, or functional exacerbation of the organ involved or new organ involvement.

Results: The patients comprised 73 men and 34 women (mean age 65.7 years). The mean follow-up periods were 64.1 (range 7–252) months, and the serum IgG4 levels at diagnosis were 706 (range 10.7–3,610) mg/dL. The 27 untreated patients had significantly lower IgG4-RD responder index (10.8 ± 5.1 vs 13.8 ± 6.8, P=0.048), fewer affected organs (1.9 ± 1.2 vs 3.0 ± 1.6, P=0.001), and lower frequency of ophthalmic and renal parenchymal lesions (25.9% vs 53.8%, P=0.015, and 3.7% vs 26.3%, P=0.012, respectively) than did the 80 patients who underwent treatment. Of these 27 patients, 8 experienced deterioration of IgG4-RD 62.8 (range 3–232) months after the diagnosis. New organ involvement was observed in all 8 patients, 2 of whom concurrently suffered exacerbation of the organs involved. In age- and sex-adjusted logistic regression analysis, serum IgG4 elevation (per 100 mg/dL, odds ratio 1.194, 95% confidence interval 1.017-1.402, P = 0.030) was the only significant factor related to deterioration of disease in untreated patients with IgG4-RD, whereas serum IgG4 levels did not relate to deterioration in patients who underwent treatment (per 100 mg/dL, odds ratio 0.995, 95% confidence interval 0.921-1.075, P = 0.901).

Conclusion: The present study suggests that serum IgG4 levels may be a useful predictor of the outcomes of untreated patients with IgG4-RD, who tend to have fewer affected organs and lower IgG4-RD responder index.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/factors-related-to-deterioration-of-igg4-related-disease-in-untreated-patients-with-igg4-related-disease/