Country-based modelling of COVID-19 case fatality rate: A multiple regression analysis

Table 1 Descriptive statistics (mean ± SD) for candidate predictor variables, R square, coefficient (SE) for univariate regression between predictors and case

Variable	Mean (SD)	R2	Beta (SD)	P value
Population density1	300.96 (1539.00)	0.027	-0.116 (0.051)	0.025
GDP per capita in 20201	15389.61 (23441.43)	0.000	0.013 (0.053)	0.812
Health Expenditure per capita1	1161.25 (1865.17)	0.176	-0.251 (0.041)	< 0.001
Population ages ≥ 70 yr	5.42 (4.22)	0.062	-0.059 (0.017)	< 0.001
Percent Obese	18.93 (9.93)	0.042	-0.021 (0.007)	0.006
Percent Diabetes	7.92 (4.09)	0.030	-0.042 (0.018)	0.018
Percent HIV1	1.91 (4.33)	0.001	0.022 (0.066)	0.743
Percent Tobacco Users	20.05 (9.55)	0.016	-0.013 (0.008)	0.116
Life expectancy at birth	72.53 (7.31)	0.157	-0.054 (0.009)	< 0.001
General death rate per 1000	7.87 (2.97)	0.017	0.044 (0.025)	0.075
Hospital beds per 1000	3.29 (2.44)	0.115	-0.145 (0.041)	< 0.001
Physicians per 1000	2.35 (1.93)	0.064	-0.197 (0.074)	0.009
Radiologist per 100 K	13.56 (5.52)	0.005	0.008 (0.026)	0.759
CT scanners per million	29.05 (20.02)	0.353	-0.932 (0.213)	< 0.001
Air pollution1	22.31 (14.73)	0.066	0.416 (0165)	0.014
Literacy rate	82.25 (17.33)	0.067	0.013 (0.006)	0.023
Human development index	0.72 (0.15)	0.178	-2.787 (0.445)	< 0.001
Tests per 1 million1	1654560.98 (2994282.33)	0.234	-0.266 (0.036)	< 0.001
Doses per 100 people	133.56 (79.68)	0.356	-0.007 (0.001)	< 0.001
Given 1+ dose	57.71 (26.97)	0.319	-0.020 (0.002)	< 0.001
Percent Fully vaccinated	52.49 (26.82)	0.341	-0.021 (0.002)	< 0.001

¹Ln Transformed.

HIV: Human immunodeficiency viruses; CT scanner: Computed tomography scanner GPD: Gross Domestic Product.

Table 2 Multiple regression results with forward method for all candidate statistically significant correlated independent variables

Model	Variable	Beta (SD)	Standardized beta	P value	R square (P value)
1	(Constant)	7.80 (1.30)		< 0.001	0.799 (< 0.001)
	Health expenditure per capita	-1.06 (0.17)	-0.894	< 0.001
2	(Constant)	3.42 (1.82)		0.093	0.895 (< 0.001)
	Health expenditure per capita	-0.79 (0.16)	-0.667	< 0.001
	Air pollution	0.93 (0.32)	0.384	0.018
3	(Constant)	4.29 (1.40)		0.016	0.947 (< 0.001)
	health Expenditure per capita	-0.69 (0.12)	-0.580	< 0.001
	Air pollution	0.91 (0.24)	0.377	0.006
	Number of CT scanners (1 million people)	-0.51 (0.18)	-0.246	0.023
4	(Constant)	3.10 (1.14)		0.030	0.974 (< 0.001)
	Health expenditure per capita	-0.58 (0.10)	-0.486	< 0.001
	Air pollution	1.01 (0.19)	0.415	< 0.001
	Number of CT scanners (per 1 million people)	-0.74 (0.16)	-0.357	0.002
	Literacy rate	0.01 (0.00)	0.199	0.031

CT scanner: Computed tomography scanner.