Investigated factors, data sources and summary statistics
| Type | Domain | Variable | Period | Source (Reference) | Mean (SD) | Range |
| Outcome | Excess mortality | Excess mortality per 100 000 population | January 2020–September 2021 | World Mortality Database14 | 160 (146) | −41.7 to 608 |
| Exposure | Democratic governance | V-Dem Liberal Democracy Index (LDI) | 2019 | V-Dem Institute15 | 0.544 (0.257) | 0.062–0.858 |
| EIU Democracy Index | 2019 | EIU18 | 6.66 (1.98) | 1.94–9.81 | ||
| Covariates | Demographic | Population age ≥65(% total) | 2019 | World Bank47 | 14.3 (6.02) | 2.00–28.0 |
| Population age ≥80(% total) | 2019 | World Bank48 | 3.58 (1.98) | 0–8.56 | ||
| Population density (people per sq. km) | 2018 | World Bank49 | 321 (1153) | 2.04–7953.0 | ||
| Population female (%) | 2019 | World Bank50 | 50.3 (3.58) | 24.7–54.1 | ||
| Economic | GDP per capita (current US$) | 2019 | World Bank51 | 24 480 (23795) | 891–1 14 685 | |
| Gini index | 2014–2019 | World Bank52 | 34.5 (6.69) | 24.6–53.4 | ||
| COVID-19 burden | Cumulative COVID-19 cases per 100 000 population | Jan 2020- Sept 2021 | Johns Hopkins University19 | 5576 (3962) | 38.7–15 649 | |
| Chronic conditions | Prevalence of cardiovascular disease (%) | 2019 | Global Burden of Disease Study53 | 9.58 (3.48) | 3.47–16.5 | |
| Prevalence of chronic respiratory disease (%) | 2019 | Global Burden of Disease Study53 | 8.13 (3.28) | 3.11–16.1 | ||
| Prevalence of diabetes and kidney diseases (%) | 2019 | Global Burden of Disease Study53 | 16.4 (3.53) | 8.94–25.4 | ||
| Prevalence of neurological disorders (%) | 2019 | Global Burden of Disease Study53 | 41.2 (4.73) | 28.4–50.9 | ||
| Prevalence of cancer (%) | 2019 | Global Burden of Disease Study53 | 11.9 (5.05) | 3.77–27.0 | ||
| Disease risk factors | Prevalence of adult obesity (BMI >30, %) | 2010–2019 | World Obesity Federation | 20.8 (7.97) | 3.60–42.7 | |
| Age-standardised mortality rate attributed to household and ambient air pollution per 100 000 population | 2016 | World Health Statistics 202054 | 42.7 (34.9) | 5.90–185.2 | ||
| Age standardised prevalence of tobacco smoking among persons aged 15 and older (%) | 2018 | World Health Statistics 202054 | 24.0 (8.54) | 6.90–44.7 | ||
| Health system | UHC Service Coverage Index | 2017 | World Bank55 | 75.2 (7.63) | 55.0–89.0 | |
| Current health expenditure per capita (current US$) | 2018 | World Bank56 | 2088 (22397) | 59.8–10 623 | ||
| Out-of-pocket expenditure (% current health expenditure) | 2018 | World Bank57 | 29.2 (16.5) | 5.99–84.3 | ||
| Vaccination | Population in receipt of at least one dose of COVID-19 vaccine (%) | Jan 2020 - August 2021 | Our World in Data58 | 43.0 (22.3) | 3.63–78.4 | |
| Proportion fully vaccinated against COVID-19 (%) | Jan 2020 - August 2021 | Our World in Data58 | 32.5 (21.7) | 0.58–74.4 | ||
| Strength of restrictive policies | COVID-19 Stringency Index | Time of 1000th Case | Oxford COVID-19 Government Response Tracker20 | 75 (22.8) | 11.1–100 |
BMI, body mass index; EIU, Economist Intelligence Unit; GDP, gross domestic product; UHC, Universal Health Coverage.