Intermediate-term follow-up and damage in IgG4-related disease: a single centre experience

Due to its progressive fibro-inflammatory nature and frequent delays in diagnosis, IgG4-related disease (IgG4-RD) carries a significant risk of permanent organ damage. An index to evaluate the damage in IgG4-RD has been developed recently. The aim of this follow-up study was to assess the prognosis of IgG4-RD, with a focus on damage progression.

Data on IgG4-RD baseline characteristics, treatment, relapses, damage progression and deaths during follow-up were retrospectively extracted from electronic medical records of patients with IgG4-RD diagnosed and monitored at our rheumatology centre. Damage was assessed using the CIC IgG4-RD Damage Index (CIC IgG4-RD DI) at baseline, 12 months, 24 months and at the last follow-up visit. Risk factors for damage at the last visit and for death were evaluated by Cox proportional-hazards regression analysis.

Of 59 patients diagnosed between January 2012 and December 2024, 55 were followed for a median (IQR) of 44.7 (20.4; 81.2) months (37/55 patients were followed for more than 24 months), while 4 were lost to follow-up. At diagnosis, 36 patients (65.5%) had already developed damage. At the 12-, 24-month visits and last follow-up visit of a subgroup followed-up for more than 24 months, 37/50 (74%), 29/37 (78.4%) and 32/37 (86.5%) patients had developed damage, respectively. A relapsing disease course was identified as a factor associated with damage at the last patient's visit (HR 5.3 (95%CI 1.1; 24,4), p=0.035). Eight patients (14.5%) died during follow-up, with 4 deaths related to IgG4-RD or its treatment. Damage at the last visit emerged as a risk factor for death (HR 1.5 (95%CI 1.0; 2.2), p=0.036).

At diagnosis, damage was already present in nearly two-thirds of our patients. During follow-up, damage progressively accumulated and was associated with patient death.