Derivative-order-dependent stability and transient behaviour in a predator–prey system of fractional differential equations

In this paper, the static and dynamic behaviour of a fractional-order predator–prey model are studied, where the nonlinear interactions between the two species lead to multiple stable states. As has been found in many previous systems, the stability of such states can be dependent on the fractional order of the time derivative, which is included as a phenomenological model of memory-effects in the predator and prey species. However, what is less well understood is the transient behaviour and dependence of the observed domains of attraction for each stable state on the order of the fractional time derivative. These dependencies are investigated using analytical (for the stability of equilibria) and numerical (for the observed domains of attraction) techniques. Results reveal far richer dynamics compared to the integer-order model. We conclude that, as well as the species and controllable parameters, the memory effect of the species will play a role in the observed behaviour of the system

A global action agenda for turning the tide on fatty liver disease

Background and Aims: Fatty liver disease is a major public health threat due to its very high prevalence and related morbidity and mortality. Focused and dedicated interventions are urgently needed to target disease prevention, treatment, and care. Approach and Results: We developed an aligned, prioritized action agenda for the global fatty liver disease community of practice. Following a Delphi methodology over 2 rounds, a large panel (R1 n = 344, R2 n = 288) reviewed the action priorities using Qualtrics XM, indicating agreement using a 4-point Likert-scale and providing written feedback. Priorities were revised between rounds, and in R2, panelists also ranked the priorities within 6 domains: epidemiology, treatment and care, models of care, education and awareness, patient and community perspectives, and leadership and public health policy. The consensus fatty liver disease action agenda encompasses 29 priorities. In R2, the mean percentage of “agree” responses was 82.4%, with all individual priorities having at least a super-majority of agreement (> 66.7% “agree”). The highest-ranked action priorities included collaboration between liver specialists and primary care doctors on early diagnosis, action to address the needs of people living with multiple morbidities, and the incorporation of fatty liver disease into relevant non-communicable disease strategies and guidance. Conclusions: This consensus-driven multidisciplinary fatty liver disease action agenda developed by care providers, clinical researchers, and public health and policy experts provides a path to reduce the prevalence of fatty liver disease and improve health outcomes. To implement this agenda, concerted efforts will be needed at the global, regional, and national levels

A global research priority agenda to advance public health responses to fatty liver disease

Background & aims An estimated 38% of adults worldwide have non-alcoholic fatty liver disease (NAFLD). From individual impacts to widespread public health and economic consequences, the implications of this disease are profound. This study aimed to develop an aligned, prioritised fatty liver disease research agenda for the global health community. Methods Nine co-chairs drafted initial research priorities, subsequently reviewed by 40 core authors and debated during a three-day in-person meeting. Following a Delphi methodology, over two rounds, a large panel (R1 n = 344, R2 n = 288) reviewed the priorities, via Qualtrics XM, indicating agreement using a four-point Likert-scale and providing written feedback. The core group revised the draft priorities between rounds. In R2, panellists also ranked the priorities within six domains: epidemiology, models of care, treatment and care, education and awareness, patient and community perspectives, and leadership and public health policy. Results The consensus-built fatty liver disease research agenda encompasses 28 priorities. The mean percentage of ‘agree’ responses increased from 78.3 in R1 to 81.1 in R2. Five priorities received unanimous combined agreement (‘agree’ + ‘somewhat agree’); the remaining 23 priorities had >90% combined agreement. While all but one of the priorities exhibited at least a super-majority of agreement (>66.7% ‘agree’), 13 priorities had 90% combined agreement. Conclusions Adopting this multidisciplinary consensus-built research priorities agenda can deliver a step-change in addressing fatty liver disease, mitigating against its individual and societal harms and proactively altering its natural history through prevention, identification, treatment, and care. This agenda should catalyse the global health community’s efforts to advance and accelerate responses to this widespread and fast-growing public health threat. Impact and implications An estimated 38% of adults and 13% of children and adolescents worldwide have fatty liver disease, making it the most prevalent liver disease in history. Despite substantial scientific progress in the past three decades, the burden continues to grow, with an urgent need to advance understanding of how to prevent, manage, and treat the disease. Through a global consensus process, a multidisciplinary group agreed on 28 research priorities covering a broad range of themes, from disease burden, treatment, and health system responses to awareness and policy. The findings have relevance for clinical and non-clinical researchers as well as funders working on fatty liver disease and non-communicable diseases more broadly, setting out a prioritised, ranked research agenda for turning the tide on this fast-growing public health threat

Clinical and Patient-Reported Outcomes From Patients With Nonalcoholic Fatty Liver Disease Across the World: Data From the Global Non-Alcoholic Steatohepatitis (NASH)/ Non-Alcoholic Fatty Liver Disease (NAFLD) Registry

Background & Aims: Globally, nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease. We assessed the clinical presentation and patient-reported outcomes (PROs) among NAFLD patients from different countries. Methods: Clinical, laboratory, and PRO data (Chronic Liver Disease Questionnaire–nonalcoholic steatohepatitis [NASH], Functional Assessment of Chronic Illness Therapy–Fatigue, and the Work Productivity and Activity Index) were collected from NAFLD patients seen in real-world practices and enrolled in the Global NAFLD/NASH Registry encompassing 18 countries in 6 global burden of disease super-regions. Results: Across the global burden of disease super-regions, NAFLD patients (n = 5691) were oldest in Latin America and Eastern Europe and youngest in South Asia. Most men were enrolled at the Southeast and South Asia sites. Latin America and South Asia had the highest employment rates (>60%). Rates of cirrhosis varied (12%–21%), and were highest in North Africa/Middle East and Eastern Europe. Rates of metabolic syndrome components varied: 20% to 25% in South Asia and 60% to 80% in Eastern Europe. Chronic Liver Disease Questionnaire–NASH and Functional Assessment of Chronic Illness Therapy–Fatigue PRO scores were lower in NAFLD patients than general population norms (all P < .001). Across the super-regions, the lowest PRO scores were seen in Eastern Europe and North Africa/Middle East. In multivariate analysis adjusted for enrollment region, independent predictors of lower PRO scores included younger age, women, and nonhepatic comorbidities including fatigue (P < .01). Patients whose fatigue scores improved over time experienced a substantial PRO improvement. Nearly 8% of Global NAFLD/NASH Registry patients had a lean body mass index, with fewer metabolic syndrome components, fewer comorbidities, less cirrhosis, and significantly better PRO scores (P < .01). Conclusions: NAFLD patients seen in real-world practices in different countries experience a high comorbidity burden and impaired quality of life. Future research using global data will enable more precise management and treatment strategies for these patients. © 2021 AGA Institut

A Global Survey of Physicians Knowledge About Nonalcoholic Fatty Liver Disease

Background & Aims: Despite rapidly increasing nonalcoholic fatty liver disease (NAFLD) prevalence, providers’ knowledge may be limited. We assessed NAFLD knowledge and associated factors among physicians of different specialties globally. Methods: NAFLD knowledge surveys containing 54 and 59 questions covering 3 domains (epidemiology/pathogenesis, diagnostics, and treatment) were completed electronically by hepatologists, gastroenterologists (GEs), endocrinologists (ENDOs), and primary care physicians (PCPs) from 40 countries comprising 5 Global Burden of Disease super-regions. Over 24 months, 2202 surveys were completed (488 hepatologists, 758 GEs, 148 ENDOs, and 808 PCPs; 50% high-income Global Burden of Disease super-region, 27% from North Africa and Middle East, 12% Southeast Asia, and 5% South Asian and Latin America). Results: Hepatologists saw the greatest number of NAFLD patients annually: median 150 (interquartile range, 60–300) vs 100 (interquartile range, 35–200) for GEs, 100 (interquartile range, 30–200) for ENDOs, and 10 (interquartile range, 4–50) for PCPs (all P <.0001). The primary sources of NAFLD knowledge acquisition for hepatologists were international conferences (33% vs 8%–26%) and practice guidelines for others (39%–44%). The Internet was the second most common source of NAFLD knowledge for PCPs (28%). NAFLD knowledge scores were higher for hepatologists than GEs: epidemiology, 62% vs 53%; diagnostics, 80% vs 73%; and treatment, 61% vs 58% (P <.0001), and ENDOs scores were higher than PCPs: epidemiology, 70% vs 60%; diagnostics, 71% vs 64%; and treatment, 79% vs 68% (P <.0001). Being a hepatologist or ENDO was associated with higher knowledge scores than a GE or PCP, respectively (P <.05). Higher NAFLD knowledge scores were associated independently with a greater number of NAFLD patients seen (P <.05). Conclusions: Despite the growing burden of NAFLD, a significant knowledge gap remains for the identification, diagnosis, and management of NAFLD. © 2021 AGA Institut

Advancing the global public health agenda for NAFLD: a consensus statement

Non-alcoholic fatty liver disease (NAFLD) is a potentially serious liver disease that affects approximately one-quarter of the global adult population, causing a substantial burden of ill health with wide-ranging social and economic implications. It is a multisystem disease and is considered the hepatic component of metabolic syndrome. Unlike other highly prevalent conditions, NAFLD has received little attention from the global public health community. Health system and public health responses to NAFLD have been weak and fragmented, and, despite its pervasiveness, NAFLD is largely unknown outside hepatology and gastroenterology. There is only a nascent global public health movement addressing NAFLD, and the disease is absent from nearly all national and international strategies and policies for non-communicable diseases, including obesity. In this global Delphi study, a multidisciplinary group of experts developed consensus statements and recommendations, which a larger group of collaborators reviewed over three rounds until consensus was achieved. The resulting consensus statements and recommendations address a broad range of topics — from epidemiology, awareness, care and treatment to public health policies and leadership — that have general relevance for policy-makers, health-care practitioners, civil society groups, research institutions and affected populations. These recommendations should provide a strong foundation for a comprehensive public health response to NAFLD. © 2021, Springer Nature Limited

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background: The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods: In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results: Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89·6 per cent) compared with that in countries with a middle (753 of 1242, 60·6 per cent; odds ratio (OR) 0·17, 95 per cent c.i. 0·14 to 0·21, P < 0·001) or low (363 of 860, 42·2 per cent; OR 0·08, 0·07 to 0·10, P < 0·001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -9·4 (95 per cent c.i. -11·9 to -6·9) per cent; P < 0·001), but the relationship was reversed in low-HDI countries (+12·1 (+7·0 to +17·3) per cent; P < 0·001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0·60, 0·50 to 0·73; P < 0·001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion: Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background: End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods: This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results: In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion: Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone