Incidence of hepatic and haematological laboratory abnormalities in 248 patients with rheumatoid arthritis over 13 years of observation
| Abnormality | n | Person-years at risk | Incidence per 100 person-years (95% CI)* |
|---|---|---|---|
| *Exact Poisson confidence limits. | |||
| AST, aspartate transaminase; CI, confidence interval; WBC, white blood cell count. | |||
| AST >40 U/l | 56 | 792 | 7.1 (5.3 to 9.2) |
| Albumin <35 g/l | 68 | 784 | 8.7 (6.7 to 11.0) |
| WBC <4.0×109/l | 18 | 927 | 1.9 (1.1 to 3.1) |
| Platelets <150×109/l | 17 | 945 | 1.8 (1.0 to 2.9) |
| Any abnormality | 111 | 560 | 20 (16 to 24) |
| Clinically severe abnormalities | |||
| AST >80 U/l | 9 | 980 | 0.9 (0.4 to 1.7) |
| Albumin <30 g/l | 11 | 990 | 1.1 (0.6 to 2.0) |
| WBC <3.0×109/l | 7 | 988 | 0.7 (0.3 to 1.5) |
| Platelets <100×109/l | 3 | 990 | 0.3 (0.1 to 0.9) |
| Any clinically severe abnormality | 27 | 930 | 2.9 (1.9 to 4.2) |