Estimated rates of respiratory infections and estimated HRs comparing risk of infection in hydroxychloroquine compared to csDMARD* (without hydroxychloroquine use)
| URI, bronchitis, pneumonia | ||||
|---|---|---|---|---|
| Rates of infection | n | Patient-years (PY) | Rate/100 PY | |
| Hydroxychloroquine | 198 | 2872 | 6.9 | |
| csDMARD | 345 | 4851 | 7.1 | |
| Total | 543 | 7722 | 7.0 | |
| HRs | Model | All Starters | Matched | |
| HR (95% CI) | HR (95% CI) | |||
| Unadjusted | 0.97 (0.82 to 1.15) | 0.94 (0.73 to 1.21) | ||
| Adjusted† | 0.87 (0.70 to 1.07) | 0.90 (0.70 to 1.17) | ||
| URI, Bronchitis | ||||
| Rates of infection | n | PY | Rate/100 PY | |
| Hydroxychloroquine | 157 | 2915 | 5.4 | |
| csDMARD | 269 | 4904 | 5.5 | |
| Total | 426 | 7819 | 5.4 | |
| HRs | Model | All Starters | Matched | |
| HR (95% CI) | HR (95% CI) | |||
| Unadjusted | 0.98 (0.81 to 1.20) | 0.95 (0.72 to 1.27) | ||
| Adjusted | 0.85 (0.68 to 1.08) | 0.93 (0.70 to 1.25) | ||
| Serious infections (URI, Bronchitis, Pneumonia) | ||||
| Rates of infection | n | PY | Rate/100 PY | |
| Hydroxychloroquine | 32 | 3062 | 1.04 | |
| csDMARD | 48 | 5123 | 0.94 | |
| Total | 80 | 8186 | 0.98 | |
| HRs | Model | All Starters | Matched | |
| HR (95% CI) | HR (95% CI) | |||
| Unadjusted | 1.12 (0.72 to 1.73) | 1.05 (0.57 to 1.95) | ||
| Adjusted | 1.29 (0.76 to 2.18) | 1.10 (0.58 to 2.12) | ||
*csDMARD medications refers to conventional disease-modifying antirheumatic drugs.
†Cox regression models adjusted for baseline characteristics and time-varying covariates including disease activity as measured by the Clinical Disease Activity Index (CDAI), prior use of 1 versus 2 or more csDMARDs, use of prednisone and its dose, season of the year, history of diabetes and history of cardiovascular disease.