Mortality in patients with primary Sjögren's syndrome: a systematic review and meta-analysis.

OBJECTIVE: It remains debated whether patients with primary Sjögren's syndrome (pSS) are at greater risk of mortality. We aimed to determine the magnitude of all-cause mortality risk in patients with pSS compared with the general population through a systematic review and meta-analysis. METHODS: We searched PubMed, EMBASE and Cochrane Library for studies published from inception to October 2020. Stata meta-analysis software was used to calculate the pooled risk estimates for mortality (standardized mortality ratio, SMR). RESULTS: Our search identified 2796 articles, of which 14 studies with 14 584 patients were eventually included for the analysis. A total of 902 deaths were observed. Overall, we found a 1.46-fold increased risk of death in pSS patients when compared with the general population [meta-standardized mortality ratio (SMR): 1.46, 95% CI: 1.10, 1.93]. Subgroup analyses showed that mortality risks were higher in European countries (meta-SMR: 1.55, 95% CI: 1.04, 2.33), in retrospective studies (meta-SMR: 1.50, 95% CI: 1.09, 2.05), in studies based on referral cohorts (meta-SMR: 1.55, 95% CI: 1.04, 2.30), in studies that enrolled >500 patients (meta-SMR: 1.70, 95% CI: 1.11, 2.61) and in studies with follow-up time longer than 8 years (meta-SMR: 1.55, 95% CI: 0.87, 2.77). Significantly greater mortality risk was found in patients with older age, male gender, vasculitis, interstitial lung disease, low complements, positive anti-La/SSB and cryoglobulinaemia. CONCLUSION: The existing data indicated ∼50% increase of mortality among patients with pSS compared with the general population. More attention should be paid to those patients with poor prognostic factors.