Figure 1.

Models for attributing tuberculosis (TB) to drug treatment. (A) “On drug”. Patient-years and adverse events were attributed to each drug only while the patient was actively receiving that drug. Event A was not attributed to any drug, while event B was attributed to drug 2. (B) “Most recent drug”. Patient-years were accrued for each drug from the start date of that drug until the date of switching to the next anti-tumour necrosis factor drug, irrespective of drug discontinuation. Follow-up was censored at the most recently completed consultant follow-up or death, whichever came first, for all models.