Table 2.

Sequential robust GEE regression models assessing predictors of BMI over all study visits and interactions with time in subjects with all necessary data available.

Variable	Model 1, n = 1474, Obs = 15,318		Model 2, n = 1474, Obs = 15,318
Variable	β (95% CI)	p	β (95% CI)	p
Time, per 100 days	−0.015 (−0.026 – −0.0032)	0.01	0.22 (0.15–0.29)	< 0.001
Baseline age, per yr, < 50	0.14 (0.047–0.23)	0.003	0.17 (0.079–0.26)	< 0.001
Baseline age, per yr, ≥ 50	−0.18 (−0.21 – −0.15)	< 0.001	−0.15 (−0.18 – −0.12)
Female	0.082 (−1.06–1.23)	0.7	0.13 (−1.01–1.28)	0.8
White	−0.41 (−1.09–0.22)	0.3	−0.40 (−1.05–0.25)	0.2
ln(CRP), mg/dl	−0.066 (−0.11 – −0.017)	0.008	0.019 (−0.061–0.097)	0.6
Prednisone use	−0.028 (−0.15–0.094)	0.7	0.015 (−0.13–0.10)	0.8
Methotrexate use	0.15 (0.021–0.28)	0.02	0.11 (−0.0073–0.23)	0.07
Anti-TNF use	0.15 (−0.034–0.33)	0.1	0.16 (−0.017–0.33)	0.08
Baseline CCP-positive	0.22 (−0.40–0.83)	0.5	0.19 (−0.43–0.81)	0.5
Baseline erosions	−1.82 (−2.36 – −1.29)	< 0.001	−1.80 (−2.34 – −1.26)	< 0.001
Baseline smoking	−2.96 (−3.58 – −2.34)	< 0.001	−2.99 (−3.61 – −2.38)	< 0.001
Interactions with observation time^*
Age × time, 1 yr of age × 100 days	—	—	−0.0038 (−0.0047 – −0.0029)	< 0.001
ln(CRP) × time, 1 unit × 100 days	—	—	−0.0079 (−0.014 – −0.0014)	0.02

↵* Interactions tested, but not significant: Prednisone Use × Time; Methotrexate Use × Time; Anti-TNF Use × Time; Baseline Erosions × Time. GEE: generalized estimating equations; BMI: body mass index; Obs: observations; CRP: C-reactive protein; TNF: tumor necrosis factor; CCP: cyclic citrullinated peptide antibodies.