Risk of Venous Thromboembolism in Patients with Sjogren’s Syndrome: A Systematic Review and Meta-analysis

Background/Purpose: Venous thromboembolism (VTE) is a common medical problem with a significant morbidity and mortality.  Chronic inflammatory state, though not generally regards as a conventional risk factor for VTE, is increasingly recognized as its potential predisposing factor.  In fact, several chronic inflammatory disorders, such as systemic lupus erythematosus and rheumatoid arthritis, have been shown to increase VTE in large epidemiologic studies.  However, the data on Sjogren’s syndrome (SS), another common chronic inflammatory disorder, remain unclear due to conflicting studies.  Thus, to further investigate this possible association, we conducted a systematic review and meta-analysis of observational studies that compared the risk of VTE in patients with SS versus participants without it.

Methods : Two investigators (P.U. and C.T.) independently searched published studies indexed in MEDLINE, EMBASE and the Cochrane database from inception to March 2014 using the terms for Sjogren’s syndrome in conjunction with the terms “venous thromboembolism”, “pulmonary embolism” and “deep venous thrombosis”.  A manual search of references of retrieved articles was also performed.  The inclusion criteria were as follows: (1) observational studies published as original studies to evaluate the association between SS and VTE and (2) odds ratios (OR’s), relative risk (RR’s) or hazard ratio (HR’s) or standardized incidence ratio (SIR’s) with 95% confidence intervals (CI’s) were provided.  Study eligibility was independently determined by the two investigators noted above. Newcastle-Ottawa scale was used to assess the quality of included studies.

RevMan 5.2 software was used for the data analysis.  Point estimates and standard errors were extracted from individual studies and were combined by the generic inverse variance method of DerSimonian and Laird.  Given the high likelihood of between study variance, we used a random-effect model rather than a fixed-effect model.  Statistical heterogeneity was assessed using the Cochran’s Q test. 

Results : Out of 382 potentially relevant articles, four studies (three retrospective cohort studies and one case-control study) were identified and included in our data analysis.  The pooled risk ratio of VTE in patients with SS was 2.04 (95% CI, 1.85 to 2.24). The statistical heterogeneity of this meta-analysis was not significant with an I² of 0%.

Conclusion : Our study demonstrated a statistically significant increased VTE risk among patients with SS.