Risk factors associated with discontinuation of pirfenidone due to an adverse drug reaction (ADR)# in the overall population
| Predictor of early discontinuation¶ | Comparison | OR (95% CI) | p-value |
| At 6 months | |||
| Age | Continuous | 1.06 (1.03–1.08) | <0.0001 |
| Female sex | Yes versus no | 1.59 (1.06–2.33) | 0.0228 |
| Steroid use prior to study | Yes versus no | 1.64 (1.10–2.43) | 0.0148 |
| At 12 months | |||
| Age | Continuous | 1.06 (1.04–1.08) | <0.0001 |
| Female sex | Yes versus no | 1.52 (1.04–2.17) | 0.0288 |
| Steroid use prior to study | Yes versus no | 1.48 (1.02–2.17) | 0.0406 |
| Underlying pulmonary disease+ | Yes versus no | 0.72 (0.50–1.03) | 0.0748 |
| During entire study | |||
| Age | Continuous | 1.03 (1.01–1.05) | 0.0009 |
| Female sex | Yes versus no | 1.54 (1.08–2.22) | 0.0193 |
| BMI | Continuous | 0.96 (0.92–0.99) | 0.0127 |
| UK patients | Yes versus no | 1.65 (1.14–2.39) | 0.0081 |
| Current alcohol use | Yes versus no | 0.73 (0.53–1.01) | 0.0555 |
| Years since IPF diagnosis | Continuous | 1.04 (0.99–1.09) | 0.1245 |
| Ex-/current smoker | Yes versus no | 1.30 (0.94–1.79) | 0.1111 |
BMI: body mass index; IPF: idiopathic pulmonary fibrosis; FVC: forced vital capacity. #: an ADR was defined as any safety event with a possible causal relationship to pirfenidone (the treating physician (investigator) made a clinical judgement to decide if the ADR was related to pirfenidone); ¶: following analysis of early discontinuation due to an ADR, the following baseline variables were included in the stepwise logistic regression model-building process: age, sex, BMI, smoking/alcohol status, steroid/azathioprine exposure, UK patient, alanine aminotransferase, FVC, years since IPF diagnosis, FVC % pred <50% and other pulmonary/hepatic/cardiovascular disease; +: other than IPF.