Prevalence of Periodontitis in Patients with Established Rheumatoid Arthritis: A Swedish Population Based Case-Control Study

Abstract

Introduction: The possible hypothesis of a link between periodontitis and rheumatoid arthritis (RA), specifically anti-citrullinated protein antibody (ACPA) positive RA, prompted us to investigate the prevalence of periodontitis in the Swedish Epidemiological Investigation of RA (EIRA), a well-characterised population-based RA case-control cohort.

Methods: Periodontal status of 2,740 RA cases and 3,942 matched controls was retrieved through linking EIRA with the National Dental Health Registry (DHR), where dental diagnostic- and treatment codes on the adult Swedish population have been registered. Dental records from 100 cases and controls were reviewed to validate the periodontal diagnostic codes in DHR.

Results: The reviewed dental records confirmed 90% of the periodontitis diagnoses in DHR among RA cases, and 88% among controls. We found the positive predictive value of periodontitis diagnoses in the DHR to be 89% (95% CI 78 to 95%) with a sensitivity of 77% (95% CI: 65 to 86%). In total, 86% of EIRA participants were identified in DHR. The risk for periodontitis increased by age and current smoking status in both cases as well as controls. No significant differences in prevalence of periodontal disease in terms of gingivitis, periodontitis, peri-implantitis or increased risk for periodontitis or peri-implantitis were observed between RA cases and controls. In addition, there was no difference on the basis of seropositivity, ACPA or rheumatoid factor (RF), among patients with RA.

Conclusions: Our data verify that smoking and ageing are risk factors for periodontitis, both in RA and controls. We found no evidence of an increased prevalence of periodontitis in patients with established RA compared to healthy controls, and no differences based on ACPA or RF status among RA subjects.

Fig 1. Study design.

Schematic overview of the study, including linkage of EIRA (Epidemiological Investigation of Rheumatoid Arthritis) with DHR (Dental Health Registry) and the validation of the diagnostic codes from DHR using dental records.

Fig 2. Prevalence of periodontitis in relation to age.

Prevalence (%) and numbers of exposed participants with periodontitis in different age groups identified in DHR demonstrating, (A) RA cases versus controls, (B) ACPA-positive versus ACPA-negative RA patients, (C) RA-women versus RA-men, (D) control-women versus control-men. Statistical differences were observed with increased age for both RA cases and controls. The differences between the groups were analysed by chi-square test or Fisher´s exact test. p-value < 0.05 was considered statistically significant.