Association between ankylosing spondylitis and chronic periodontitis: a population-based study.

OBJECTIVE: Ankylosing spondylitis (AS) is one type of chronic inflammatory rheumatic disease. It has been suggested that rheumatic diseases may have additional underlying factors in common with chronic periodontitis. However, few studies have addressed the possible link between AS and chronic periodontitis. We undertook the present case-control study to investigate the possible association between AS and chronic periodontitis using a population-based data set in Taiwan.
METHODS: We conducted this study by using administrative claims data sourced from the Taiwan National Health Insurance program database. Our study included 6,821 AS patients and 34,105 randomly selected controls. Conditional logistic regression analyses were performed to calculate the odds ratios (ORs) and 95% confidence intervals (95% CIs) for prior chronic periodontitis among AS patients and matched controls.
RESULTS: There was a significant difference in the prevalence of prior chronic periodontitis between patients and controls (41.5% versus 25.9%; P<0.001). Conditional logistic regression analysis revealed that patients were more likely than controls to have been previously diagnosed as having chronic periodontitis (adjusted OR 1.84 [95% CI 1.74-1.98]). We further found that patients were only 1.70 (95% CI 1.56-1.89) times more likely than controls to have undergone a gingivectomy or periodontal flap operation (all patients had a history of chronic periodontitis) within the 5 years preceding the index date. After excluding those who had undergone either a gingivectomy or periodontal flap surgery, patients were even more likely than controls to have been previously diagnosed as having chronic periodontitis (adjusted OR 2.04 [95% CI 1.93-2.15]).
CONCLUSION: This study detected an association between AS and a prior diagnosis of chronic periodontitis.