Global Prevalence of Spondyloarthritis: A Systematic Review and Meta-Regression Analysis.

OBJECTIVE: To summarize the prevalence of spondyloarthritis (SpA) and its subtypes in the general population, and to identify demographic and methodologic characteristics that might explain heterogeneity in prevalence estimates.

METHODS: A systematic literature search was performed to identify relevant articles. Risk of bias was assessed and data were extracted. Pooled prevalences were calculated. Potential sources of heterogeneity were explored by subgroup analysis and meta-regression analysis.

RESULTS: The prevalence of SpA ranged from 0.20% (95% confidence interval [95% CI] 0.00-0.66) in South-East Asia to 1.61% (95% CI 1.27-2.00) in Northern Arctic communities; the prevalence of ankylosing spondylitis (AS) from 0.02% (95% CI 0.00-0.21) in Sub-Saharan Africa to 0.35% (95% CI 0.24-0.48) in Northern Arctic communities; and the prevalence of psoriatic arthritis (PsA) from 0.01% (95% CI 0.00-0.17) in the Middle East to 0.19% (95% CI 0.16-0.32) in Europe. The following characteristics were significantly associated with variation in prevalence of SpA, AS, and/or PsA: proportion of females, mean age of the sample, geographic area and setting (demographic characteristics), year of data collection, case finding, and case ascertainment (methodologic characteristics). For the other SpA subgroups, too few studies were available to conduct a meta-analysis, but prevalence estimates of reactive arthritis (range 0.0-0.2%), SpA related to inflammatory bowel disease (range 0.0-0.1%), and undifferentiated SpA (range 0.0-0.7%) were generally low.

CONCLUSION: SpA is a common disease, but with large variation in reported prevalence estimates, which can partly be explained by differences in demographic and methodologic characteristics. Particularly, geographic area as well as case finding account for a substantial part of the heterogeneity.