Table 2

Prevalence of periodontitis of rheumatoid arthritis patients compared with the age- and gender-matched control population

DPSI category

Patients with RA

(n = 95)

Control population

(n = 420)

P value

Relative risk

95% CI

A: No periodontitis, percentage

30

70

< 0.001

B: Moderate periodontitis, percentage

43

18

< 0.001

3.6

2.3-5.5

C: Severe periodontitis, percentage

27

12

< 0.001

3.7

2.4-5.9

CI, confidence interval; DPSI, Dutch periodontal screening index; RA, rheumatoid arthritis.

Smit et al. Arthritis Research & Therapy 2012 14:R222   doi:10.1186/ar4061