Table 3

Expected and observed numbers and rates of serious infections for V.1 (per 100 patient-years) and V.2 (% of patients with at least one serious infection during 12 months)

 nPYV.1: Number of serious infections per 100 PY (CI)V.2: Number and percentage of patients affected by at least one serious infection per year (CI)
Exp. nObs. nExp. rate/100 PYObs. rate/100 PYExp. nObs. nExp. per year (%)Obs. per year (%)
TNFα inhibitor, no risk factor764105916.8161.61.5 (0.9–2.5)15.3161.41.5 (0.9–2.5)
nbDMARD, no risk factor6328167.060.90.7 (0.3–1.6)6.460.80.7 (0.3–1.6)
TNFα inhibitor, ≥1 risk factor*, no GC63587128.9373.34.3 (3.0–5.9)25.4332.93.8 (2.6–5.3)
nbDMARD, ≥1 risk factor*, no GC67493915.5191.72.0 (1.2–3.2)14.0191.52.0 (1.2–3.2)
TNFα inhibitor + GC, no other risk factor2251968.654.42.6 (0.8–6.0)7.443.82.0 (0.6–5.2)
nbDMARD + GC, no other risk factor128861.922.22.3 (0.3–8.4)1.722.02.3 (0.3–8.4)
TNFα inhibitor, ≥1 risk factor* + GC20616015.3119.66.9 (3.4–12.3)12.8118.06.9 (3.4–12.3)
nbDMARD, ≥1 risk factor* + GC141965.185.38.3 (3.6–16.4)4.484.68.3 (3.6–16.4)
TNFα inhibitor total1830228669.6693.03.0 (2.33.8)60.9642.72.8 (2.23.7)
nbDMARD total1575193729.6351.51.8 (1.22.5)26.6351.41.8 (1.22.5)
  • Bold: The confidence intervals of the observed rates overlap with the expected rates. There is no other test for insignificant difference necessary or sensible.

  • *At least one of: chronic lung disease, chronic renal disease, age above 60 years, previous serious infection, high number of DMARD failures. GC: treatment with glucocorticoids ≥7.5 mg/day prednisolone equivalent.

  • exp, expected; obs, observed; nbDMARD, non-biological disease-modifying antirheumatic drug; PY, patient-years; TNF, tumour necrosis factor.