Damage accrual predicts the development of lymphoma in primary Sjögren's disease

To study whether damage and its kinetics are associated with mortality and lymphoma development in primary Sjögren's disease (pSjD).

Single-centre retrospective cohort study including patients with pSjD. Damage was assessed yearly using the Sjögren Syndrome (SS) damage index (DI) (SSDI) and SS Disease DI (SSDDI) scores. Early damage: damage occurring in the first year after diagnosis; early damage increase: increase of ≥1 point in the first 5 years. SSDDI and SSDI scores' domains were compared with two-sample test of proportions. Cox regression was performed to investigate predictors of mortality and lymphoma. A p<0.05 was considered statistically significant.

We included 208 patients with pSjD (female: 93.8%; mean age at diagnosis/onset: 49.9±14.9/45.6±15.0 years; mean follow-up time: 14.1±9.2 years). Damage affected 79.3% and 85.1% patients, using SSDDI and SSDI scores, respectively. Age at diagnosis (per one-unit increase HR 1.1, 95%CI 1.1-1.2) and at onset (per one-unit increase HR 1.1, 95%CI 1.0-1.2) predicted mortality. Damage and early damage increase did not predict mortality with either score. Seventeen patients (8.2%) developed lymphoma. Early damage increases predicted lymphoma in both scores (SSDDI: HR 14.5, 95% CI 1.8-115; SSDI: HR 12.8, 95% CI 1.5-108.1). Early damage variation, damage variation, and cumulative damage were also predictors of lymphoma.

Although damage was not associated with mortality, age at diagnosis and onset of symptoms were risk factors for mortality in pSjD. Cumulative and evolving damage, especially in the first years of disease, should raise concern about the possible development of lymphoma in these patients.