Table 2.

Associations of patient characteristics with baseline QTc interval.

Variables	Univariate Models		Extended MV Model		Reduced MV Model
Variables	β	p	β	p	β	p
Age, per year	−0.12	0.48
Male	−1.62	0.73
Any CVD risk factors	−3.71	0.38
RA duration, per month	−0.0021	0.93
RF > 40 units	5.75	0.13	1.16	0.74
Anti-CCP > 20 units	11.51	0.004	7.94	0.038	8.31	0.021
DAS28, per unit	3.82	0.012
SJC, per joint	1.48	0.005	0.91	0.18	1.01	0.038
TJC, per joint	0.67	0.090	0.091	0.85
Log SDAI, per unit	1.89	0.60
Log CRP, per mg/dl	5.30	0.001	3.74	0.016	3.69	0.016
√ESR, per mm/h	1.48	0.095
Log MMP-3, per ng/ml	8.24	< 0.001	5.12	0.018	5.16	0.015
VAS, per mm	0.13	0.074
mVAS, per mm	−0.012	0.89
HAQ, per unit	6.65	0.047	2.87	0.42
Any DMARD	−3.05	0.51
MTX	1.24	0.76
MTX dose, mg	0.42	0.32
Other DMARD	−0.39	0.94
Prednisolone	1.28	0.73
Prednisolone dose, per mg/day	0.81	0.21
Adjusted R²			0.239	< 0.001	0.255	< 0.001

β coefficients represent the average difference in baseline QTc interval per 1 unit higher of the indicated independent variable from linear regression modeling. The first column of univariate models represents individual models in which the indicated independent variable is the only covariate in the model. The MV models are single models containing each of the listed covariates. R² represents the proportion of the variability of the baseline QTc interval explained by the covariates in the model. MV: multivariable; RA: rheumatoid arthritis; CVD: cardiovascular disease; RF: rheumatoid factor; anti-CCP: anticyclic citrullinated peptide; DAS28: 28-joint count Disease Activity Score; SJC: swollen joint count; TJC: tender joint count; SDAI: Simplified Disease Activity Index; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; MMP: matrix metalloproteinase; VAS: visual analog scale; mVAS: modified VAS; DMARD: disease-modifying antirheumatic drug; QTc: corrected electrocardiographic QT interval; HAQ: Health Assessment Questionnaire; MTX: methotrexate.