Table 4.

The results of single-factor and multi-factor negative binomial regression analysis for COVID-19 in 178 countries/regions

	Incidence rate (IR)								Cumulative mortality rate (CMR)								Daily cumulative index (DCI)
Indicators	IRR*	95%CI† (Lower)	95%CI (Upper)	p-value	aIRR‡	95%CI (Lower)	95%CI (Upper)	p-value	IRR	95%CI (Lower)	95%CI (Upper)	p-value	aIRR	95%CI (Lower)	95%CI (Upper)	p-value	IRR	95%CI (Lower)	95%CI (Upper)	p-value	aIRR	95%CI (Lower)	95%CI (Upper)	p-value
Urban Development
Urban population (% of total population)	1.048	0.992	1.106	0.096					1.055	1.027	1.083	<0.001	1.027	1.010	1.044	0.001	1.073	1.055	1.091	<0.001	1.022	1.010	1.034	<0.001
Urban population growth (annual %)	1.053	1.039	1.066	<0.001	0.866	0.670	1.120	0.273	0.287	0.203	0.405	<0.001	0.751	0.507	1.112	0.153	0.407	0.312	0.530	<0.001	0.993	0.734	1.343	0.963
Population density (people per sq. km of land area)	1.000	1.000	1.000	0.179					1.000	1.000	1.000	0.633					1.000	1.000	1.000	<0.001	1.000	1.000	1.000	0.020
Economy & Growth GDP per capita (current 1,000 US$) Health	1.054	1.038	1.071	<0.001	1.029	1.013	1.045	<0.001	1.086	1.056	1.117	<0.001	1.031	1.021	1.041	<0.001	1.045	1.019	1.072	0.001	0.998	0.987	1.009	0.696
People using at least basic sanitation services (% of population)	1.063	1.048	1.078	<0.001	1.022	1.005	1.039	0.010	1.088	1.065	1.111	<0.001	1.001	0.985	1.018	0.897	1.056	1.045	1.066	<0.001	1.011	0.998	1.025	0.102
Current health expenditure (% of GDP)	1.186	1.045	1.345	0.008	1.088	0.956	1.238	0.203	1.501	1.245	1.809	<0.001	1.211	1.040	1.410	0.013	1.416	1.216	1.648	<0.001	1.080	0.968	1.206	0.169
Death rate, crude (per 1,000 people)	0.954	0.862	1.057	0.371					1.097	0.857	1.403	0.462					1.187	0.978	1.439	0.082
Domestic private health expenditure (% of current health expenditure)	0.955	0.933	0.978	<0.001	0.988	0.972	1.004	0.135	0.937	0.906	0.969	<0.001	0.986	0.970	1.003	0.102	0.951	0.933	0.970	<0.001	1.010	0.994	1.027	0.207
Domestic private health expenditure per capita (current US$)	1.003	1.002	1.003	<0.001	1.001	1.000	1.001	0.119	1.005	1.003	1.008	<0.001	1.001	1.000	1.001	0.104	1.003	1.001	1.004	<0.001	1.000	1.000	1.001	0.438
Hospital beds (per 1,000 people)	1.246	1.034	1.502	0.021	0.906	0.790	1.039	0.156	1.798	1.067	3.030	0.028	0.799	0.696	0.916	0.001	1.302	1.022	1.659	0.033	0.731	0.641	0.833	<0.001
Net migration	1.000	1.000	1.000	<0.001	1.000	1.000	1.000	0.954	1.000	1.000	1.000	0.001	1.000	1.000	1.000	0.530	1.000	1.000	1.000	0.005	1.000	1.000	1.000	0.103
Nurses and midwives (per 1,000 people)	1.239	1.149	1.337	<0.001	0.901	0.813	1.002	0.052	1.499	1.268	1.773	<0.001	0.837	0.749	0.936	0.002	1.290	1.111	1.498	0.001	0.904	0.820	0.997	0.044
Physicians (per 1,000 people)	1.938	1.393	2.698	<0.001	1.005	0.750	1.347	0.972	3.389	2.652	4.331	<0.001	1.725	1.191	2.498	0.004	2.600	1.739	3.886	<0.001	0.951	0.758	1.192	0.661
Population ages 65 and above (% of total population)	1.111	1.054	1.171	<0.001	0.981	0.913	1.055	0.609	1.235	1.151	1.326	<0.001	1.066	0.968	1.173	0.192	1.233	1.144	1.328	<0.001	1.062	0.988	1.141	0.102
Proportion of population spending more than 25% of household consumption or income on out-of-pocket health care expenditure (%)	0.802	0.675	0.953	0.012	0.846	0.750	0.955	0.007	0.794	0.626	1.007	0.057					0.898	0.715	1.129	0.357
Infrastructure
Railways, passengers carried (million passenger-km)	1.000	1.000	1.000	<0.001	1.000	1.000	1.000	0.323	1.000	1.000	1.000	0.679					1.000	1.000	1.000	0.498
Poverty
Poverty headcount ratio at national poverty lines (% of population)	0.924	0.900	0.949	<0.001	0.970	0.948	0.993	0.011	0.894	0.872	0.916	<0.001	0.960	0.940	0.982	<0.001	0.908	0.889	0.926	<0.001	0.963	0.945	0.982	<0.001
Science & Technology
Researchers in R&D (per million people)	1.000	1.000	1.001	<0.001	1.000	1.000	1.000	0.159	1.000	1.000	1.001	0.034	1.000	1.000	1.000	0.115	1.001	1.001	1.001	<0.001	1.000	1.000	1.001	0.012
Social Protection & Labor
Coverage of social insurance programs (% of population)	1.060	1.041	1.079	<0.001	1.047	1.009	1.086	0.014	1.036	0.992	1.082	0.110					1.091	1.072	1.110	<0.001	1.015	0.991	1.039	0.214
Unemployment, total (% of total labor force) (national estimate)	0.902	0.828	0.982	0.018	0.956	0.909	1.004	0.072	1.002	0.861	1.166	0.984					0.986	0.866	1.122	0.828
Climate
Mean temperature (Celsius)	0.934	0.897	0.972	0.001	1.039	0.992	1.088	0.105	0.975	0.887	1.071	0.592					0.834	0.800	0.869	<0.001	0.978	0.939	1.018	0.280
Relative humidity (%)	1.011	0.994	1.027	0.204					1.025	0.995	1.056	0.108					0.990	0.960	1.022	0.538
Mean wind speed (.1 knots);	1.210	1.111	1.317	<0.001	1.040	0.957	1.130	0.358	1.155	0.951	1.403	0.146					0.958	0.836	1.097	0.533
Precipitation amount (.01 inches).	0.082	0.016	0.003	0.003	0.477	0.126	1.808	0.276	0.019	0.001	0.377	0.009	0.425	0.123	1.471	0.177	0.204	0.005	8.409	0.402

^*IRR, incidence rate ratio.

^†CI is short for confidence interval.

^‡aIRR, adjusted incidence rate ratio.