Table 2.

Univariable and multivariable linear regression analyses of serum R–SH at baseline in mild COVID-19 with clinical and biochemical parameters.

	Univariable analysis		Multivariable analysis
	St. βa	p-value	St. βa	p-value
Age	−0.55	<0.001
Female sex	−0.10	0.273
BMI	−0.24	0.008	−0.29	0.049
Current smoking	−0.06	0.476
Level of education – college level or higher	0.20	0.023
Biometrics
Respiratory rateb	−0.21	0.025
Pulse	−0.07	0.489
Comorbidities
Cardiovascular	−0.15	0.085
Pulmonary	−0.07	0.443
Metabolic	−0.08	0.353
Inflammatory/autoimmune	−0.10	0.274
Malignancy	−0.07	0.481
Neurological	−0.06	0.506
Hematological	−0.01	0.873
Gastrointestinal	0.16	0.073
Laboratory measurements
Hemoglobin (g/dL)	0.05	0.580
CRP (mg/L)b	−0.36	<0.001
WBC (x109/L)b	−0.12	0.199
Platelets (x109/L)	−0.01	0.933
Albumin (g/L)	0.59	<0.001
Total bilirubin (μmol/L)b	0.13	0.159
ALT (U/L)b	−0.34	<0.001
AST (U/L)b	−0.31	<0.001	−0.75	<0.001
AP (U/L)b	−0.28	0.002
GGT (U/L)b	−0.49	<0.001
eGFR (mL/min x 1.73 m2)	0.53	<0.001
Creatinine (μmol/L)b	−0.19	0.033
PCS
at 3 months	0.01	0.920
at 6 months	0.00	0.996
at 12 months	−0.11	0.278
at 18 months	−0.08	0.511

P-values <0.05 were considered statistically significant (indicated in bold).

Abbreviations: ALT, alanine aminotransferase; AP, alkaline phosphatase; AST, aspartate aminotransferase; BMI, body mass index; CRP, C-reactive protein; eGFR, estimated glomerular filtration rate; GGT, gamma-glutamyl transferase; HC, healthy controls; PCS, post-COVID-19 syndrome; WBC, white blood cell count.

^aStandardized beta (St. β) coefficient represents the difference in serum R–SH concentrations per 1-SD increment/decrement for continuous variables and the difference in serum R–SH concentrations compared to the reference group for categorical variables.

^bSkewed variables were log-transformed before entering the linear regression analyses.