Table 2. Univariable analysis of demographic, clinical manifestation, patient-reported clinical outcomes, and psychosocial variables.

	Main effect		Interaction between independent variable and time-in-study
Independent Variable	b (95% CI)	p-value	b (95% CI)	p-value
Follow-up time	−0.01 (−0.04, 0.01)	0.221
Demographic
Age	0.01 (−0.01, 0.01)	0.793	0.01 (−0.01,0.01)	0.31
Gender, female	0.08 (−0.20, 0.35)	0.579	−0.03(−0.09, 0.02)	0.255
Ethnicity, Caucasian	0.17 (−0.04, 0.37)	0.111	0.02(−0.02, 0.07)	0.287
Exercise habits	−0.31 (−0.52, −0.09)	0.004	0.02 (−0.02, 0.07)	0.367
Marital Status	−0.18 (−0.38−0.03)	0.093	0.01 (−0.04, 0.05)	0.919
Clinical manifestations
Disease duration	0.01 (−0.05, 0.08)	0.658	0.01 (−0.01, 0.02)	0.752
Diffuse cutaneous involvement	−0.20 (−0.41, 0.01)	0.059	−0.01 (−0.05, 0.04)	0.971
Dysphagia	0.27 (0.07, 0.47)	0.009	−0.03 (−0.07, 0.02)	0.232
Diarrhea	0.28 (0.08, 0.48)	0.006	−0.03 (−0.07, 0.02)	0.221
BMI*	0.01 (−0.01, 0.02)	0.554	0.01 (−0.01, 0.01)	0.401
Small joint contracture	0.32 (0.05, 0.59)	0.021	−0.02 (−0.08, 0.04)	0.587
mRSS**	0.01 (−0.01, 0.02)	0.251	−0.01 (−0.01, 0.01)	0.947
No of comorbidities	0.06 (−0.01, 0.12)	0.089	0.01 (−0.01, 0.02)	0.954
Serum creatinine level	0.19 (0.02, 0.36)	0.033	−0.01 (−0.07, 0.06)	0.928
Hematocrit	0.01 (−0.02, 0.03)	0.889	0.01 (−0.01, 0.01)	0.106
Cardiac involvement	0.31 (−0.01, 0.62)	0.051	−0.02 (−0.1, 0.05)	0.538
Antibody profile
Anti-centromere antibody	−0.16 (−0.47, 0.16)	0.329	0.01(−0.06, 0.08)	0.782
Anti-topoisomerase antibody	−0.12 (−0.39, 0.14)	0.359	0.03 (−0.03, 0.09)	0.298
Anti-polymerase III antibody	0.04 (−0.20, 0.27)	0.774	0.01 (−0.05, 0.05)	0.948
U1-RNP	0.42 (0.09, 0.74)	0.012	−0.04 (−0.12, 0.04)	0.376
FVC† % predicted value	−0.01 (−0.01, 0.01)	0.204	−0.01 (−0.01, 0.01)	0.06
DLco‡ % predicted value	−0.01 (−0.01, 0.01)	0.135	−0.01 (−0.01, 0)	0.013
Medsger Severity Index
General	0.02 (−0.11, 0.15)	0.721	0.01 (−0.03, 0.03)	0.969
Perivascular	0.01 (−0.09, 0.10)	0.956	−0.01 (−0.03, 0.12)	0.447
Skin	0.07 (−0.05, 0.19)	0.259	0.01 (−0.03, 0.03)	0.992
Joint	0.08 (−0.01, 0.16)	0.059	0.01 (−0.02, 0.02)	0.915
Muscle	0.19 (−0.06, 0.43)	0.133	0.01 (−0.04, 0.06)	0.713
GI Tract	0.23 (0.08, 0.39)	0.004	0.01 (−0.4, 0.05)	0.819
Lung	0.04 (−0.05, 0.14)	0.346	0.01 (−0.01, 0.03)	0.250
Heart	0.06 (−0.09, 0.19)	0.439	0.03 (−0.01, 0.07)	0.208
Kidney	0.20 (−0.03, 0.44)	0.090	0.06 (−0.03, 0.15)	0.21
Patient-reported clinical outcome
VASβ for pain	0.06 (0.03, 0.09)	<0.001	−0.01 (−0.01, 0.01)	0.522
VASβ for dypnea	0.09 (0.05, 0.12)	<0.001	−0.01 (−0.01, 0.01)	0.994
Psychosocial measures
IBQΩ	0.06 (0.04, 0.08)	<0.001	−0.01 (−0.01, 0.01)	0.093
ISELΨ	−0.01 (−0.08, 0.06)	0.787	−0.01 (−0.02, 0.02)	0.959

*BMI: Body mass index;

**mRSS: modified Rodnan Skin Score;

^†FVC: Forced vital capacity;

^‡DLco: Diffuse capacity of the lung for carbon monoxide;

^βVAS: Visual Analogue Scale;

^ΩIBQ: Illness Behavior Questionnaire;

^ΨISEL: Interpersonal Support Evaluation List.