Incidence rate (per 1000 person-years) of incident RA in the propensity score-matched HCV cohort
| RA event (%) | Number of patients | Person-years | Incidence rate | |
| Treated cohort | 28 (1.4) | 1966 | 6928 | 4.0 |
| Untreated cohort | 277 (3.5) | 7864 | 50 259 | 5.5 |
HCV, hepatitis C virus; RA, rheumatoid arthritis.