Univariable linear regression of factors associated with excess mortality per 100 000 for all countries
| Variable | Change in excess mortality per 100 000 for one-unit change in variable | P value | 95% CI |
| V-Dem Liberal Democracy Index (LDI) | −1.50 | 0.016 | −2.71 to −0.29 |
| EIU Democracy Index | −20.3 | 0.009 | −35.5 to −5.15 |
| Age ≥65 years (%) | 4.37 | 0.60 | −0.99 to 9.73 |
| Age ≥80 years (%) | 10.2 | 0.21 | −5.84 to 26.3 |
| Log population density (ppl/sqm) | −13.5 | 0.22 | −35.2 to 8.23 |
| Population female (%) | 8.80 | 0.04 | 0.47 to 17.1 |
| GDP per capita (current US $) | −0.002 | <0.001 | −0.004 to −0.001 |
| Gini index | 1.85 | 0.49 | −3.49 to 7.18 |
| Cumulative COVID-19 cases | 0.01 | 0.002 | 0.005 to 0.02 |
| Prevalence of cardiovascular disease (%) | 16.2 | 0.001 | 7.18 to 25.2 |
| Prevalence of chronic respiratory disease (%) | −5.83 | 0.23 | −15.4 to 3.77 |
| Prevalence of diabetes and kidney diseases (%) | 8.58 | 0.08 | −0.97 to 18.1 |
| Prevalence of neurological disorders (%) | 5.02 | 0.20 | −2.75 to 12.8 |
| Prevalence of cancer (%) | 7.28 | 0.02 | 1.19 to 13.4 |
| Prevalence of adult obesity (BMI >30, %) | 0.69 | 0.33 | −3.45 to 4.83 |
| Age-standardised mortality rate attributed to household and ambient air pollution per 100 000 population | 0.70 | 0.13 | −0.22 to 1.62 |
| Age standardised prevalence of tobacco smoking among persons aged 15 and older (%) | 5.81 | 0.003 | 2.07 to 9.56 |
| UHC Service Index | −4.98 | 0.02 | −8.95 to −1.02 |
| Current health expenditure per capita (US$) | −0.02 | 0.003 | −0.03 to −0.007 |
| Out-of-pocket expenditure (% current health expenditure) | 2.12 | 0.03 | 0.24 to 3.99 |
| Population in receipt of at least one dose of COVID-19 vaccine (%) | −1.92 | 0.006 | −3.26 to −0.58 |
| Proportion fully vaccinated against COVID-19 (%) | −1.13 | 0.12 | −2.57 to 0.30 |
| Stringency Index (at 1000th case) | 0.95 | 0.17 | −0.41 to 0.23 |
BMI, body mass index; EIU, Economist Intelligence Unit; GDP, gross domestic product; UHC, Universal Health Coverage.