Table 2.
Association between antibiotic prescriptions and RA
| Variables | Controls | Cases | Crude OR (95% CI) | Adjusted ORa (95% CI) | ||
|---|---|---|---|---|---|---|
| N | % | N | % | |||
| Any antibiotic use | ||||||
| No prescriptions | 16,242 | 18.0 | 2369 | 10.4 | Reference | Reference |
| ≥ 1 prescription | 73,771 | 82.0 | 20,308 | 89.6 | 2.02 (1.92–2.12) | 1.60 (1.51–1.68) |
| No. of prescriptions (quartile) (median (IQR)) | ||||||
| 1 (1 (1, 2)) | 20,321 | 22.6 | 4128 | 18.2 | 1.49 (1.41–1.57) | 1.40 (1.32–1.48) |
| 2 (4 (3, 5)) | 18,923 | 21.0 | 4592 | 20.2 | 1.85 (1.75–1.96) | 1.66 (1.57–1.77) |
| 3 (8 (7, 9)) | 17,524 | 19.5 | 5231 | 23.1 | 2.36 (2.23–2.50) | 2.04 (1.92–2.17) |
| 4 (19 (14, 29)) | 17,003 | 18.9 | 6357 | 28.0 | 3.10 (2.93–3.28) | 2.56 (2.39–2.74) |
| Recency of therapy (therapy termination)b | ||||||
| 1–2 years before diagnosis | 30,041 | 35.2 | 9557 | 43.9 | 2.34 (2.23–2.46) | 1.80 (1.70–1.90) |
| 2–5 years before diagnosis | 26,898 | 31.5 | 7016 | 32.2 | 1.91 (1.81–2.01) | 1.57 (1.49–1.66) |
| 5–10 years before diagnosis | 12,183 | 14.3 | 2846 | 13.1 | 1.70 (1.59–1.80) | 1.48 (1.39–1.58) |
| Antibiotic type | ||||||
| Bacteriostatic | ||||||
| Unexposedc | 43,580 | 48.4 | 8778 | 38.7 | Reference | Reference |
| Exposed | 46,433 | 51.6 | 13,899 | 61.3 | 1.55 (1.50–1.60) | 1.31 (1.27–1.36) |
| Bactericidal | ||||||
| Unexposedd | 21,892 | 24.3 | 3595 | 15.9 | Reference | Reference |
| Exposed | 68,121 | 75.7 | 19,082 | 84.2 | 1.80 (1.72–1.87) | 1.45 (1.39–1.51) |
aAdjusted for age, BMI, smoking status, Charlson comorbidity index, alcohol, and infections
bMost recent course of therapy
cIncluding those people exposed only to bactericidal antibiotics
dIncluding those people exposed only to bacteriostatic antibiotics