Background: The global burden of sepsis, a life-threatening dysregulated host response to infection leading to organ dysfunction, remains challenging to quantify. We aimed to comprehensively estimate the global, regional, and national burden of sepsis, including the impact of the COVID-19 pandemic and underlying causes of sepsis-related deaths with co-occurring infectious syndromes. Methods: We used multiple cause-of-death, hospital, minimally invasive tissue sampling, and linked death certificate and hospital record data representing 149 million deaths, covering 4290 location-years with mortality estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 to capture explicit and implicit sepsis cases and deaths. We estimated age-location-sex-specific fractions of sepsis-related deaths from 195 underlying causes of death and 22 infectious syndromes from 1990 to 2021 using binomial logistic regression models, and estimated sepsis-related deaths using GBD cause-specific mortality estimates. Using 250 million hospital admissions and 7·82 million deaths from hospital data, representing 1310 location-years, we modelled case fatality rates by use of binomial logistic regression, applied to sepsis death estimates to estimate sepsis incidence by age, location, and year. Findings: In 2021, we estimated 166 million (95% uncertainty interval 135–201) sepsis cases and 21·4 million (20·3–22·5) all-cause sepsis-related deaths globally, representing 31·5% of total global deaths. Sepsis-related deaths decreased between 1990 and 2019, followed by a surge in 2020 and 2021. As of 2021, individuals aged 15 years and older experienced increases across incidence (230%) and mortality (26·3%) since 1990. Those aged 70 years and older had the highest sepsis-related mortality in 2021 (9·28 million [8·74–9·86] deaths). Sepsis-related deaths from infectious underlying causes decreased from 11·8 million (11·1–12·5) in 1990 to 8·34 million (7·72–9·01) in 2019, then increased by 86·4% to 15·5 million (14·7–16·4) in 2021. Sepsis-related mortality due to non-infectious underlying causes of death increased from 4·69 million (4·35–5·05) in 1990 to 5·81 million (5·40–6·25) in 2021; the leading non-infectious underlying causes of death with sepsis were stroke, chronic obstructive pulmonary disease, and cirrhosis. In 2021, bloodstream infections inclusive of HIV and malaria (3·08 million [2·83–3·35]) and lower respiratory infections inclusive of COVID-19 (11·33 million [1·20–1·47]) were the most prominent infectious syndromes complicating sepsis-related deaths from non-infectious underlying causes, representing a consistent trend since 1990. Interpretation: The global burden of sepsis increased in 2020 and 2021, reversing progress from 1990. Sepsis incidence and mortality increased in people aged 15 years and older, especially those aged 70 years and older, and as a complication of non-infectious underlying causes of death such as stroke, primarily through bloodstream infections and lower respiratory infections. The global burden of sepsis is substantial, and sepsis is increasingly a complication of non-infectious causes of death. Funding: Gates Foundation, Wellcome Trust, and Department of Health and Social Care using UK aid funding managed by the Fleming Fund.

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease, is one of the most prevalent liver diseases globally, contributing to both economic and health-related challenges. We aimed to evaluate the global, regional, and national burden of MASLD from 1990 to 2023, quantify the contribution of identified modifiable risk factors, and project future prevalence up to the year 2050. Methods: Estimates of MASLD prevalence and disability-adjusted life-years (DALYs) were produced by age, sex, region, Socio-demographic Index (SDI), and Healthcare Access and Quality (HAQ) index across 204 countries and territories from 1990 to 2023 as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2023. The MASLD burden attributable to three risk factors (smoking, high BMI, and high fasting plasma glucose) was assessed as part of the GBD comparative risk assessment. As a secondary analysis, we used these estimates to forecast MASLD prevalence up to 2050 using fasting plasma glucose and mean BMI as predictors. Furthermore, to examine the relative contributions of population ageing, population growth, and changes in MASLD prevalence rate to the forecasted changes in case counts from 2023 to 2050, we conducted a decomposition analysis. Findings: In 2023, approximately 1·3 billion (95% uncertainty interval [UI] 1·2 to 1·4) individuals were estimated to be living with MASLD (ie, 16·1% of the global population), with an age-standardised prevalence rate of 14 429·3 (95% UI 13 268·3 to 15 990·6) per 100 000 population, representing a percentage increase of 142·7% (95% UI 139·2 to 146·7) in crude numbers from 1990 (0·5 billion [0·5 to 0·6]) and of 28·6% (27·8 to 29·5) in the rate (11 217·2 [10 276·8 to 12 467·0] per 100 000 in 1990). An estimated 3·6 million (2·8 to 4·5) total DALYs were attributable to MASLD worldwide in 2023, corresponding to an age-standardised DALY rate of 39·6 (31·2 to 49·9) per 100 000 population. Despite a 116·3% (93·3 to 139·4) increase in crude DALYs (from 1·7 million [1·3 to 2·1] in 1990), its age-standardised estimate remained consistent (1·8% [–8·6 to 12·8]) from 1990 (38·9 [30·1 to 49·8] per 100 000) to 2023. There was substantial variation in age-standardised estimates across regions. North Africa and the Middle East had the highest prevalence rate (29 246·1 [26 848·3 to 32 048·7] per 100 000) and Andean Latin America showed the highest DALY rate (152·3 [114·1 to 194·7] per 100 000). By contrast, the high-income Asia Pacific region had the lowest prevalence rate (8653·5 [7923·7 to 9592·8] per 100 000) and east Asia had the lowest DALY rate (16·3 [13·5 to 19·9] per 100 000) among all GBD regions. North Africa and the Middle East showed disproportionately higher prevalence rates relative to other regions with similar SDIs. Lower SDIs and HAQs were associated with higher age-standardised DALY rates. The age-standardised prevalence rate was consistently higher in males (15 616·4 [14 349·2 to 17 263·3] per 100 000 people in 2023) than in females (13 245·2 [12 132·0 to 14 692·6] per 100 000 people), and peaked at age 80–84 years in both sexes. The number of MASLD prevalent cases was the highest in younger adults, peaking at age 35–39 years for males and age 55–59 years for females. Among the risk factors for MASLD, high fasting plasma glucose presented the largest contribution to the age-standardised DALY rate of total MASLD in 2023 (2·2 [95% UI 1·6 to 3·1] per 100 000 people), followed by high BMI (1·4 [0·6 to 2·4] per 100 000 people) and smoking (1·0 [0·3 to 1·8] per 100 000 people). Our forecasting model estimates that 1·8 billion (95% UI 1·6 to 2·0) individuals are likely to have MASLD by 2050, representing a 42·0% increase from 2023. The age-standardised prevalence rate is expected to increase to 15 774·9 (95% UI 14 613·9 to 17 336·2) per 100 000 people in 2050, representing an average annual percentage change of 0·3% (95% UI 0·3–0·3). According to our decomposition analysis, this change will be primarily due to population growth, particularly in sub-Saharan Africa and North Africa and Middle East, and less by population ageing or epidemiological change. Interpretation: With a global prevalence of 16·1% and approximately 1·3 billion people already living with MASLD in 2023, the condition has and will continue to have substantial health and economic impacts worldwide. An inverse association between the HAQ Index and age-standardised DALY rates suggests that countries with lower health-care access and quality might be less well positioned to manage the growing MASLD burden, underscoring the need for strengthened health-system capacity in these settings. Funding: Gates Foundation.