Table 5.
Incidence and incidence rate ratios of visits for oral ulceration and temporomandibular joint disorders in the rheumatoid arthritis cohort and the comparison cohort
| Disorder | Age group (years) | Rheumatoid arthritis cohort | Comparison cohort | IRR (95% CI) | aIRR (95% CI) | ||||
|---|---|---|---|---|---|---|---|---|---|
| (ICD-9-CM) | No. of patient | Person-years | Incidence | No. of patient | Person-years | Incidence | p value | P value | |
| Oral ulcerationa (528.2) | |||||||||
| Overall | 222 | 7057 | 31.46 | 1734 | 70,434 | 24.62 |
1.28 (1.11–1.47) 0.001 |
1.24 (1.08–1.44)0.003 | |
| Sex | |||||||||
| Male | 34 | 1539 | 22.09 | 351 | 15,880 | 22.10 |
1.00 (0.70–1.42) 0.999 |
1.05 (0.73–1.50) 0.804 |
|
| Female | 188 | 5518 | 34.07 | 1383 | 54,554 | 25.35 |
1.34 (1.15–1.56) < 0.001 |
1.29 (1.10–1.51) 0.002 |
|
| Age group (years) | |||||||||
| 20–54 | 121 | 4117 | 29.39 | 934 | 41,241 | 22.65 |
1.30 (1.07–1.57) 0.007 |
1.30 (1.06–1.58) 0.011 |
|
| > 55 | 101 | 2940 | 34.35 | 800 | 29,193 | 27.40 |
1.25 (1.02–1.54) 0.032 |
1.21 (0.98–1.50) 0.083 |
|
| Temporomandibular joint disordersb (524.6) | |||||||||
| Overall | 18 | 7697 | 2.34 | 117 | 76,580 | 1.53 |
1.53 (0.93–2.51) 0.093 |
1.31 (0.77–2.23) 0.320 |
|
| Sex | |||||||||
| Male | 2 | 1660 | 1.20 | 23 | 17,083 | 1.35 |
0.90 (0.21–3.80) 0.881 |
0.79 (0.18–3.42) 0.750 |
|
| Female | 16 | 6037 | 2.65 | 94 | 59,497 | 1.58 |
1.68 (0.99–2.85) 0.056 |
1.33 (0.75–2.36) 0.327 |
|
| Age group (years) | |||||||||
| 20–54 | 11 | 4448 | 2.47 | 70 | 44,502 | 1.57 |
1.57 (0.83–2.97) 0.163 |
1.40 (0.72–2.76) 0.323 |
|
| > 55 | 7 | 3249 | 2.15 | 47 | 32,078 | 1.47 |
1.47 (0.66–3.25) 0.341 |
1.24 (0.52–2.96) 0.630 |
|
Adjusted for age, sex, socioeconomic status, geographic region, hypertension, diabetes, congestive heart failure, chronic pulmonary disease, cancer, dyslipidemia, coronary artery disease, prior myocardial infarction, peripheral vascular disease, cerebrovascular disease, dementia, musculoskeletal disorders, peptic ulcer disease, chronic kidney disease, and liver disease
aIRR, adjusted incidence rate ratio; ICD-9-CM, International Classification of Diseases, Ninth revision, clinical modification; IRR, incidence rate ratio
aPatients who were diagnosed with oral ulceration within 90 days before the index date were excluded and 1326 patients with rheumatoid arthritis and 13,275 controls were included in the analysis
bPatients who were diagnosed with temporomandibular joint disorders within 90 days before the index date were excluded and 1302 patients with rheumatoid arthritis and 13,229 controls were included in the analysis