TNF and infection: Using the “receiving treatment” model of analysis (Figure 2a), the crude rate of serious infection was 39.2 per 1,000 person-years in the DMARD cohort and 55.5 per 1,000 person-years in the anti-TNFα cohort, ranging from 50.4 to 63.0 events per 1,000 person-years in the 3 anti-TNFα drug cohorts (Table 2).