Table 2 Performance of methods of reporting ACR and DAS28 criteria based on onset of action according to their discriminatory capacity and their ability to reflect inhibition of structural damage progression or patient satisfaction
First ACR50 achieved inFirst monthFirst 2 monthsFirst 3 monthsFirst 4 monthsFirst 5 monthsFirst 6 months
First LDAS achieved inFirst monthFirst 2 monthsFirst 3 monthsFirst 4 monthsFirst 5 monthsFirst 6 months
Overall success, n/N (%)45/636 (7.08)117/636 (18.40)199/636 (31.29)234/636 (36.79)279/636 (43.87)302/636 (47.48)
NNS*, n55516159597158
Structural damage at year 1†, LR+ (95% CI)2.05 (1.09 to 3.84)1.60 (1.09 to 2.34)1.58 (1.22 to 2.05)1.47 (1.17 to 1.85)1.32 (1.08 to 1.62)1.24 (1.02 to 1.51)
Patient satisfaction at month 6‡, LR+ (95% CI)10.31 (1.44 to 74.10)6.62 (2.49 to 17.59)4.43 (2.42 to 8.10)3.98 (2.36 to 6.72)4.80 (2.85 to 8.07)5.21 (3.10 to 8.75)
Overall success, n/N (%)26/636 (4)65/636 (10)117/636 (18)154/636 (24)193/636 (30)218/636 (34)
NNS*, n257207242157116104
Structural damage at year 1†, LR+ (95% CI)1.59 (0.65 to 3.85)1.40 (0.79 to 2.49)1.62 (1.10 to 2.37)1.52 (1.10 to 2.09)1.36 (1.02 to 1.80)1.31 (1.01 to 1.70)
Patient satisfaction at month 6‡, LR+ (95% CI)Infinite7.27 (1.80 to 29.29)3.16 (1.59 to 6.31)2.16 (1.32 to 3.54)2.27 (1.46 to 3.53)2.59 (1.67 to 4.02)
  • The total number of patients for each analysis was: *n  =  638; †n  =  610; ‡n  =  632; categories overlap, so patients experiencing a response in the first month will also be counted in all other categories. A lower number of patients needed to study (NNS) value indicates greater discriminatory capacity; higher positive likelihood ratio (LR+) values indicate a greater probability of observing no structural damage or satisfaction with treatment. Abatacept and placebo treatment groups were pooled for radiographic progression and patient satisfaction and unpooled for NNS. ACR, American College of Rheumatology; LDAS, low disease activity state (disease activity score in 28 joints (DAS28) (C-reactive protein) ⩽3.2).