Table 3

Univariable and multivariable generalised estimating equation analysis (ASDAS model)

Low education (n=153)
High education (n=123)
VariableB95% CIpB95% CIpB95% CIp
Age (years)0.26−0.04 to 0.550.090.02−0.40 to 0.450.920.17−0.26 to 0.600.43
Male gender−6.78−13.58 to 0.020.05−0.93−10.39 to 8.530.85−2.68−12.41 to 7.060.59
High education−7.91−14.70 to −1.120.02N/A†N/A†
ASDAS12.4610.45 to 14.48<0.0113.0811.05 to 15.11<0.0110.517.10 to 13.91<0.01
BASDAI (0–10)7.736.87 to 8.58<0.01
Patient global assessment (0–10)5.554.89 to 6.21<0.01
NSAID, current−0.30−5.11 to 4.520.90§§
csDMARD, current4.76−1.20 to 10.720.12§§
bDMARD/tsDMARD, current−2.47−7.19 to 2.240.30§§
Time, post-onset versus pre-pandemic*5.321.82 to 8.82<0.019.575.63 to 13.51<0.011.49−5.39 to 8.360.67
  • Variables that were possibly associated with the outcome in univariable analysis (p<0.10) were considered for multivariable analysis. Next, these were retained in multivariable models if they were significantly associated with the outcome (p<0.05). Age, gender and the primary variable of interest (time, post-onset vs pre-pandemic) were always included.

  • *Binary time-varying variable, indicating whether an assessment took place after onset of pandemic versus pre-pandemic (primary variable of interest). As patients were followed up over time, they could have both pre-pandemic assessments (before March 2020, coded 0) and post-onset assessments (after March 2020, coded 1).

  • †Used for stratification.

  • ‡Due to collinearity, ASDAS, BASDAI and Patient global assessment were not included in the same model.

  • §Not associated with outcome in univariable analysis.

  • ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; bDMARD, biological disease-modifying antirheumatic drug; csDMARD, conventional synthetic disease-modifying antirheumatic drug; N/A, not applicable; NSAID, non-steroidal anti-inflammatory drug; tsDMARD, targeted synthetic disease-modifying antirheumatic drug.