Table 4

Sensitivity analyses comparing adjusted OR (aOR) with 95% CI for rheumatoid arthritis on the basis of different periodontitis exposure definitions and reference groups

Sensitivity analysesaOR (95% CI)
Various periodontitis exposure definitions†‡
 Periodontitis (ICD9-CM: 523.3–5)1.16 (1.12 to 1.20)
 Chronic periodontitis (ICD9-CM: 523.4)1.16 (1.09 to 1.22)
 Acute or chronic periodontitis (ICD9-CM: 523.3–4)1.17 (1.12 to 1.21)
 Periodontal or gingival diseases (ICD9-CM: 523.x)1.17 (1.13 to 1.21)
Reference group: patients who never had a coding of periodontitis (ICD9-CM: 523.3–5)
 Periodontitis (ICD9-CM: 523.3–5)†1.18 (1.14 to 1.23)
 Dental scaling ≤2 times a year with a coding of ICD9-CM: 523.3–51.05 (1.00 to 1.09)*
  • *p Value=0.051.

  • †Patients with periodontitis exposure are patients who had dental visits with corresponding ICD9-CM codes and received concurrent antibiotic treatment, or periodontal treatment other than dental scaling, or dental scaling more than twice a year.

  • ‡Reference groups are patients without the corresponding conditions.

  • Matched variables include age group, sex and year of index date. Adjusted variables include geographical region and pre-existing diseases, including diabetes requiring antidiabetic drugs and Sjögren's syndrome with a certificate of catastrophic illness.

  • aOR, adjusted OR; ICD9-CM, International Classification of Diseases, 9th Revision, Clinical Modification.