Burden of disease scenarios for 204 countries and territories, 2022–2050: a forecasting analysis for the Global Burden of Disease Study 2021

Background: Future trends in disease burden and drivers of health are of great interest to policy makers and the public at large. This information can be used for policy and long-term health investment, planning, and prioritisation. We have expanded and improved upon previous forecasts produced as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) and provide a reference forecast (the most likely future), and alternative scenarios assessing disease burden trajectories if selected sets of risk factors were eliminated from current levels by 2050. Methods: Using forecasts of major drivers of health such as the Socio-demographic Index (SDI; a composite measure of lag-distributed income per capita, mean years of education, and total fertility under 25 years of age) and the full set of risk factor exposures captured by GBD, we provide cause-specific forecasts of mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) by age and sex from 2022 to 2050 for 204 countries and territories, 21 GBD regions, seven super-regions, and the world. All analyses were done at the cause-specific level so that only risk factors deemed causal by the GBD comparative risk assessment influenced future trajectories of mortality for each disease. Cause-specific mortality was modelled using mixed-effects models with SDI and time as the main covariates, and the combined impact of causal risk factors as an offset in the model. At the all-cause mortality level, we captured unexplained variation by modelling residuals with an autoregressive integrated moving average model with drift attenuation. These all-cause forecasts constrained the cause-specific forecasts at successively deeper levels of the GBD cause hierarchy using cascading mortality models, thus ensuring a robust estimate of cause-specific mortality. For non-fatal measures (eg, low back pain), incidence and prevalence were forecasted from mixed-effects models with SDI as the main covariate, and YLDs were computed from the resulting prevalence forecasts and average disability weights from GBD. Alternative future scenarios were constructed by replacing appropriate reference trajectories for risk factors with hypothetical trajectories of gradual elimination of risk factor exposure from current levels to 2050. The scenarios were constructed from various sets of risk factors: environmental risks (Safer Environment scenario), risks associated with communicable, maternal, neonatal, and nutritional diseases (CMNNs; Improved Childhood Nutrition and Vaccination scenario), risks associated with major non-communicable diseases (NCDs; Improved Behavioural and Metabolic Risks scenario), and the combined effects of these three scenarios. Using the Shared Socioeconomic Pathways climate scenarios SSP2-4.5 as reference and SSP1-1.9 as an optimistic alternative in the Safer Environment scenario, we accounted for climate change impact on health by using the most recent Intergovernmental Panel on Climate Change temperature forecasts and published trajectories of ambient air pollution for the same two scenarios. Life expectancy and healthy life expectancy were computed using standard methods. The forecasting framework includes computing the age-sex-specific future population for each location and separately for each scenario. 95% uncertainty intervals (UIs) for each individual future estimate were derived from the 2·5th and 97·5th percentiles of distributions generated from propagating 500 draws through the multistage computational pipeline. Findings: In the reference scenario forecast, global and super-regional life expectancy increased from 2022 to 2050, but improvement was at a slower pace than in the three decades preceding the COVID-19 pandemic (beginning in 2020). Gains in future life expectancy were forecasted to be greatest in super-regions with comparatively low life expectancies (such as sub-Saharan Africa) compared with super-regions with higher life expectancies (such as the high-income super-region), leading to a trend towards convergence in life expectancy across locations between now and 2050. At the super-region level, forecasted healthy life expectancy patterns were similar to those of life expectancies. Forecasts for the reference scenario found that health will improve in the coming decades, with all-cause age-standardised DALY rates decreasing in every GBD super-region. The total DALY burden measured in counts, however, will increase in every super-region, largely a function of population ageing and growth. We also forecasted that both DALY counts and age-standardised DALY rates will continue to shift from CMNNs to NCDs, with the most pronounced shifts occurring in sub-Saharan Africa (60·1% [95% UI 56·8–63·1] of DALYs were from CMNNs in 2022 compared with 35·8% [31·0–45·0] in 2050) and south Asia (31·7% [29·2–34·1] to 15·5% [13·7–17·5]). This shift is reflected in the leading global causes of DALYs, with the top four causes in 2050 being ischaemic heart disease, stroke, diabetes, and chronic obstructive pulmonary disease, compared with 2022, with ischaemic heart disease, neonatal disorders, stroke, and lower respiratory infections at the top. The global proportion of DALYs due to YLDs likewise increased from 33·8% (27·4–40·3) to 41·1% (33·9–48·1) from 2022 to 2050, demonstrating an important shift in overall disease burden towards morbidity and away from premature death. The largest shift of this kind was forecasted for sub-Saharan Africa, from 20·1% (15·6–25·3) of DALYs due to YLDs in 2022 to 35·6% (26·5–43·0) in 2050. In the assessment of alternative future scenarios, the combined effects of the scenarios (Safer Environment, Improved Childhood Nutrition and Vaccination, and Improved Behavioural and Metabolic Risks scenarios) demonstrated an important decrease in the global burden of DALYs in 2050 of 15·4% (13·5–17·5) compared with the reference scenario, with decreases across super-regions ranging from 10·4% (9·7–11·3) in the high-income super-region to 23·9% (20·7–27·3) in north Africa and the Middle East. The Safer Environment scenario had its largest decrease in sub-Saharan Africa (5·2% [3·5–6·8]), the Improved Behavioural and Metabolic Risks scenario in north Africa and the Middle East (23·2% [20·2–26·5]), and the Improved Nutrition and Vaccination scenario in sub-Saharan Africa (2·0% [–0·6 to 3·6]). Interpretation: Globally, life expectancy and age-standardised disease burden were forecasted to improve between 2022 and 2050, with the majority of the burden continuing to shift from CMNNs to NCDs. That said, continued progress on reducing the CMNN disease burden will be dependent on maintaining investment in and policy emphasis on CMNN disease prevention and treatment. Mostly due to growth and ageing of populations, the number of deaths and DALYs due to all causes combined will generally increase. By constructing alternative future scenarios wherein certain risk exposures are eliminated by 2050, we have shown that opportunities exist to substantially improve health outcomes in the future through concerted efforts to prevent exposure to well established risk factors and to expand access to key health interventions

Machine learning models for mitral valve replacement: A comparative analysis with the Society of Thoracic Surgeons risk score

Background Current Society of Thoracic Surgeons (STS) risk models for predicting outcomes of mitral valve surgery (MVS) assume a linear and cumulative impact of variables. We evaluated postoperative MVS outcomes and designed mortality and morbidity risk calculators to supplement the STS risk score. Methods Data from the STS Adult Cardiac Surgery Database for MVS was used from 2008 to 2017. The data included 383,550 procedures and 89 variables. Machine learning (ML) algorithms were employed to train models to predict postoperative outcomes for MVS patients. Each model's discrimination and calibration performance were validated using unseen data against the STS risk score. Results Comprehensive mortality and morbidity risk assessment scores were derived from a training set of 287,662 observations. The area under the curve (AUC) for mortality ranged from 0.77 to 0.83, leading to a 3% increase in predictive accuracy compared to the STS score. Logistic Regression and eXtreme Gradient Boosting achieved the highest AUC for prolonged ventilation (0.82) and deep sternal wound infection (0.78 and 0.77) respectively. EXtreme Gradient Boosting performed the best with an AUC of 0.815 for renal failure. For permanent stroke prediction all models performed similarly with an AUC around 0.67. The ML models led to improved calibration performance for mortality, prolonged ventilation, and renal failure, especially in cases of reconstruction/repair and replacement surgery. Conclusions The proposed risk models complement existing STS models in predicting mortality, prolonged ventilation, and renal failure, allowing healthcare providers to more accurately assess a patient's risk of morbidity and mortality when undergoing MVS

The "free" right internal thoracic artery: a versatile and durable conduit.

To access publisher's full text version of this article click on the hyperlink at the bottom of the pageDespite its potential advantages, the right internal thoracic artery (RITA) is used as a conduit in only 4% of coronary revascularizations. To broaden its application, we frequently use the RITA as a free graft. In this study, we review our experience with the RITA as an in situ and free graft.We reviewed the perioperative outcomes and angiographic patency rates of 479 consecutive patients who underwent RITA grafting between January 1987 and December 2011.The RITA was harvested free (FRITA) in 380 patients (79%) and in situ in 99 (21%). The predominant target for the in situ RITA was the right coronary system (79%). The predominant targets for the FRITA were divided between the right (54%) and left coronary systems (46%). There was no perioperative mortality. Mean follow-up was 10 years. Perioperative complications included myocardial infarction (0.4%), sternal nonunions (0.4%), and reoperation for hemorrhage (0.6%). Coronary angiograms were performed in symptomatic patients (17%) after a median of seven years. FRITA patency rates at five, 10, and 15 years were 100%, 95%, and 95%, respectively, comparable to the left internal thoracic artery patency rates and superior to those of saphenous vein graft. Survival rates of FRITA patients at 10, 15, and 20 years were 92%, 89%, and 76%, respectively.The FRITA graft reaches all distal coronary vessels and is associated with excellent patency and survival rates. Its application in coronary revascularization vastly expands the benefits of internal thoracic artery grafting

Pseudoprolapse of the anterior leaflet in chronic ischemic mitral regurgitation: identification and repair.

To access publisher full text version of this article. Please click on the hyperlink in Additional Links field.Recurrence rates as high as 30% have been observed 6 months after treatment of chronic ischemic mitral regurgitation (CIMR) with isolated annuloplasty. We postulated that the high early recurrence rates resulted from the presence of untreated pseudoprolapse of the anterior leaflet. We conducted a retrospective study of all mitral valve repairs for CIMR performed by a single surgeon (S.W.H.) from 1995 to 2011. After annuloplasty, Gore-Tex neochordae were added if the high-pressure saline test indicated the presence of pseudoprolapse of the anterior leaflet. A total of 47 patients underwent mitral valve repair for CIMR. Of the 47 patients, 24 (51%) were found to have pseudoprolapse requiring the addition of neochordae. For all patients, the average age was 65.1 years, and 65.2% were men. Fourteen (30%) had had a preoperative intra-aortic balloon pump placed by cardiologists. Fourteen (30%) had severe pulmonary hypertension. Concomitant coronary artery bypass grafting was performed in 40 patients, with an average of 2.2 grafts; 7 had previously undergone coronary artery bypass grafting. Mitral Carpentier-Edwards physio annuloplasty rings were used in all patients with a mean size of 29 mm. One patient died postoperatively. Follow-up data were available for all 47 patients at an average of 4.9 years. The 5-year survival rate was 82.5%. The mean pre- and postoperative New York Heart Association class, ejection fraction, and mitral regurgitation grade were 3 and 1.52 (P < .0001), 34% and 41% (P = .0006), and 3.51 and 1.08 (P < .0001), respectively. Two patients developed greater than moderate mitral regurgitation. Effective repair of CIMR should include surgical techniques to correct pseudoprolapse of the anterior leaflet, when present. The selective addition of Gore-Tex neochordae to an undersized annuloplasty nearly eliminates recurrent regurgitation after mitral valve repair for CIMR