Table 5.

Factors related to intensity of COVID-19 related headache, multivariate analysis.

Variables	B	Odds ratio	Sig	95.0% confidence interval for B		Correlations			Collinearity statistics
				Lower bound	Upper bound	Zero-order	Partial	Part	Tolerance	VIF
Constant	0.429		0.803	−3.002	3.860
Lymphocyte count	0.000	0.065	0.577	0.000	0.001	−0.025	0.078	0.058	0.807	1.239
CRP (mg/L)	0.000	−0.004	0.976	−0.013	0.013	0.281	0.004	−0.003	0.607	1.647
D-dimer	0.306	0.055	0.649	−1.034	1.645	0.172	0.063	.048	0.742	1.348
Ferritin (ng/mL)	0.001	0.206	0.144	0.000	0.002	0.221	0.202	0.154	0.563	1.776
Primary headache	0.097	0.021	0.878	−1.168	1.363	0.124	0.021	0.016	0.599	1.669
Dehydration	1.332	0.274	0.024*	0.180	2.483	0.292	0.306	0.241	0.775	1.290
Fever	1.346	0.247	0.046*	0.027	2.664	0.339	0.273	0.213	0.745	1.342
Moderate COVID-19	0.587	0.112	0.369	−0.711	1.885	0.237	0.125	0.094	0.711	1.406
Severe COVID-19	0.031	0.004	0.977	−2.088	2.150	0.115	0.004	0.003	0.497	2.011
Age	−0.010	−0.057	0.700	−0.064	0.043	0.141	−0.054	−0.040	0.495	2.021
Sex	1.897	0.399	0.006*	0.558	3.236	0.252	0.367	0.296	0.549	1.823
Smoking	1.724	0.176	0.144	−0.608	4.055	0.119	0.202	0.154	0.769	1.301
Comorbidities	1.119	0.209	0.221	−0.694	2.932	0.377	0.169	0.129	0.378	2.644
Dependent variable: VAS (intensity), adjusted R2 0.3.

CRP: C-reactive protein; VAS: visual analog scale; VIF: variance inflation factor.

Note: Bold p-values < 0.05 are considered significant.