Associations between the presence of erosions and/or ACPA on the change of DAS and HAQ over time*
| Maximum follow-up duration | 6 months | 12 months | 6 months | 12 months |
| P value† | P value† | Β (95% CI) | Β(95% CI) | |
| Interactions with time | Stratified analyses: evolution over time (per month) | |||
| DAS | ||||
| Ero− ACPA− | 0.481 | 0.551 | −0.24 (−0.27 to −0.22) | −0.11 (−0.12 to −0.10) |
| Ero+ ACPA− | 0.001 | <0.001 | −0.30 (−0.34 to −0.26) | −0.14 (−0.16 to −0.12) |
| Ero− ACPA+ | Ref. | Ref. | −0.24 (−0.25 to −0.22) | −0.11 (−0.11 to −0.099) |
| Ero+ ACPA+ | <0.001 | <0.001 | −0.30 (−0.32 to −0.29) | −0.12 (−0.13 to −0.12) |
| HAQ | ||||
| Ero− ACPA− | 0.035 | 0.121 | −0.081 (−0.096 to −0.065) | −0.034 (−0.040 to −0.027) |
| Ero+ ACPA− | 0.072 | 0.034 | −0.084 (−0.10 to −0.064) | −0.038 (−0.047 to −0.029) |
| Ero− ACPA+ | Ref | Ref | −0.062 (−0.072 to −0.053) | −0.027 (−0.031 to −0.023) |
| Ero+ ACPA+ | <0.001 | 0.047 | −0.086 (-0.095 to −0.078) | −0.033 (-0.037 to −0.029) |
N patients=4623.
*Results stem from multivariable linear mixed models analyses with random intercept and slope and exchangeable covariance matrix, adjusted for age, gender, smoking, symptom duration, BMI, initial medication and country. Results are shown after a maximum follow-up duration of 6 months and of 12 months. Regression coefficients represent the units of change in the outcome per unit of time, in this case, per month. Missing data were imputed using multiple chained equations (40 cycles).
†P values are only shown for the interaction between erosions/ACPA and time in months. In the presence of a statistically significant interaction, results are stratified and the evolution of DAS and HAQ over time is shown for the erosions/ACPA groups separately.
BMI, body mass index; DAS, Disease Activity Score; HAQ, Health Assessment Questionnaire.