Metabolic Dysfunction-Associated Fibrosis 5 (MAF-5) Score Predicts Liver Fibrosis Risk and Outcome in the General Population With Metabolic Dysfunction.

BACKGROUND & AIMS: There is an unmet need for noninvasive tests to improve case-finding and aid primary care professionals in referring patients at high risk of liver disease. METHODS: A metabolic dysfunction-associated fibrosis (MAF-5) score was developed and externally validated in a total of 21,797 individuals with metabolic dysfunction in population-based (National Health and Nutrition Examination Survey 2017-2020, National Health and Nutrition Examination Survey III, and Rotterdam Study) and hospital-based (from Antwerp and Bogota) cohorts. Fibrosis was defined as liver stiffness ≥8.0 kPa. Diagnostic accuracy was compared with FIB-4, nonalcoholic fatty liver disease fibrosis score (NFS), LiverRisk score and steatosis-associated fibrosis estimator (SAFE). MAF-5 was externally validated with liver stiffness measurement ≥8.0 kPa, with shear-wave elastography ≥7.5 kPa, and biopsy-proven steatotic liver disease according to Metavir and Nonalcoholic Steatohepatitis Clinical Research Network scores, and was tested for prognostic performance (all-cause mortality). RESULTS: The MAF-5 score comprised waist circumference, body mass index (calculated as kg / m2), diabetes, aspartate aminotransferase, and platelets. With this score, 60.9% was predicted at low, 14.1% at intermediate, and 24.9% at high risk of fibrosis. The observed prevalence was 3.3%, 7.9%, and 28.1%, respectively. The area under the receiver operator curve of MAF-5 (0.81) was significantly higher than FIB-4 (0.61), and outperformed the FIB-4 among young people (negative predictive value [NPV], 99%; area under the curve [AUC], 0.86 vs NPV, 94%; AUC, 0.51) and older adults (NPV, 94%; AUC, 0.75 vs NPV, 88%; AUC, 0.55). MAF-5 showed excellent performance to detect liver stiffness measurement ≥12 kPa (AUC, 0.86 training; AUC, 0.85 validation) and good performance in detecting liver stiffness and biopsy-proven liver fibrosis among the external validation cohorts. MAF-5 score >1 was associated with increased risk of all-cause mortality in (un)adjusted models (adjusted hazard ratio, 1.59; 95% CI, 1.47-1.73). CONCLUSIONS: The MAF-5 score is a validated, age-independent, inexpensive referral tool to identify individuals at high risk of liver fibrosis and all-cause mortality in primary care populations, using simple variables.

Development, validation, and prognostic evaluation of a risk score for long-term liver-related outcomes in the general population: a multicohort study.

BACKGROUND: Liver cirrhosis is a major cause of death worldwide. Cirrhosis develops after a long asymptomatic period of fibrosis progression, with the diagnosis frequently occurring late, when major complications or cancer develop. Few reliable tools exist for timely identification of individuals at risk of cirrhosis to allow for early intervention. We aimed to develop a novel score to identify individuals at risk for future liver-related outcomes. METHODS: We derived the LiverRisk score from an international prospective cohort of individuals from six countries without known liver disease from the general population, who underwent liver fibrosis assessment by transient elastography. The score included age, sex, and six standard laboratory variables. We created four groups: minimal risk, low risk, medium risk, and high risk according to selected cutoff values of the LiverRisk score (6, 10, and 15). The model's discriminatory accuracy and calibration were externally validated in two prospective cohorts from the general population. Moreover, we ascertained the prognostic value of the score in the prediction of liver-related outcomes in participants without known liver disease with median follow-up of 12 years (UK Biobank cohort). FINDINGS: We included 14 726 participants: 6357 (43·2%) in the derivation cohort, 4370 (29·7%) in the first external validation cohort, and 3999 (27·2%) in the second external validation cohort. The score accurately predicted liver stiffness in the development and external validation cohorts, and was superior to conventional serum biomarkers of fibrosis, as measured by area under the receiver-operating characteristics curve (AUC; 0·83 [95% CI [0·78-0·89]) versus the fibrosis-4 index (FIB-4; 0·68 [0·61-0·75] at 10 kPa). The score was effective in identifying individuals at risk of liver-related mortality, liver-related hospitalisation, and liver cancer, thereby allowing stratification to different risk groups for liver-related outcomes. The hazard ratio for liver-related mortality in the high-risk group was 471 (95% CI 347-641) compared with the minimal risk group, and the overall AUC of the score in predicting 10-year liver-related mortality was 0·90 (0·88-0·91) versus 0.84 (0·82-0·86) for FIB-4. INTERPRETATION: The LiverRisk score, based on simple parameters, predicted liver fibrosis and future development of liver-related outcomes in the general population. The score might allow for stratification of individuals according to liver risk and thus guide preventive care. FUNDING: European Commission under the H20/20 programme; Fondo de Investigación Sanitaria de Salud; Instituto de Salud Carlos III; Spanish Ministry of Economy, Industry, and Competitiveness; the European Regional Development Fund; and the German Ministry of Education and Research (BMBF).

Metabolic dysfunction-associated fatty liver disease and excessive alcohol consumption are both independent risk factors for mortality.

BACKGROUND AND AIMS: MAFLD often cooccurs with excessive alcohol consumption, while its prognostic value in this group remains unclear. We aimed to study the mortality risk of MAFLD in relation to excessive alcohol consumption and its potential interactions. APPROACH AND RESULTS: We analyzed persons 25-74 years old enrolled in the National Health and Nutrition Examination Survey III cohort with available steatosis and alcohol data. Participants with viral hepatitis, body mass index < 18.5, and missing data on age or follow-up were excluded, leaving 12,656 participants for analysis with a median follow-up of 22.9 [20.9-24.8] years. MAFLD was defined as steatosis on ultrasound in the presence of metabolic dysfunction. Daily alcohol intake of ≥10 g in females and ≥20 g in males was considered excessive alcohol consumption. We quantified mortality risk with multivariate Cox regression for MAFLD and excessive alcohol consumption. Models were adjusted for age, age squared, sex, race, marital status, education, and smoking. MAFLD was present in 31% and excessive alcohol consumption in 13% and were both independently and simultaneously associated with increased mortality risk in fully adjusted models (adjusted HR [aHR], 1.21; 95% CI, 1.13-1.30 and aHR, 1.14; 95% CI, 1.04-1.26, respectively). Similarly, MAFLD was associated with increased mortality risk in participants with and without excessive alcohol consumption. Participants with both MAFLD and excessive alcohol consumption (4.0%) expressed the highest mortality risk (aHR, 1.47; 95% CI, 1.28-1.71). Results were consistent using the initial 10 years of follow-up, a stringent definition of excessive alcohol, and propensity score weighting. CONCLUSIONS: MAFLD increases mortality risk independent of excessive alcohol consumption. This underscores the importance of MAFLD, even in patients with excessive alcohol consumption.

Fatty liver disease is not associated with increased mortality in the elderly: A prospective cohort study.

BACKGROUND AND AIMS: Fatty liver disease (FLD) has been associated with excess mortality. Screening for hepatic steatosis (HS) in patients with metabolic dysfunction is therefore recommended by several guidelines, despite a paucity of evidence on the clinical relevance of FLD in this specific subgroup. APPROACH AND RESULTS: We studied participants of an ongoing prospective cohort (the Rotterdam Study). Persons ≥65 years old were enrolled from 2009 to 2014 and were followed through 2018. Steatosis was assessed by ultrasound and liver stiffness (LS) by transient elastography. The association between HS and LS with mortality was assessed using Cox regression analysis adjusted for age, sex, education, smoking, individual components of metabolic syndrome (MetS), heart failure, coronary heart disease, and stroke. We included 4093 elderly participants (74.4 ± 6.6 years old; 42.7% male); 36.8% had ultrasound-based steatosis. During the median follow-up of 6.9 years, 793 participants died (29.6 per 1000 person-years). In the overall population, steatosis was not associated with mortality in multivariable analysis (adjusted HR [aHR], 0.87; 95% CI, 0.73-1.03). Findings were consistent across a range of clinically relevant subgroups, including age categories, sex, MetS, elevated liver enzymes, and cardiac disease. Sensitivity analyses showed similar results for mortality beyond 5 years of follow-up and cancer-related and cerebro-cardiovascular mortality. Furthermore, among participants with steatosis, higher LS (aHR, 1.04 per kPa; 95% CI, 0.95-1.14) was not associated with mortality. CONCLUSIONS: Presence of FLD was not associated with mortality in this cohort nor in a range of subgroups. This indicates that screening for FLD and/or fibrosis is unlikely to improve outcomes among the elderly population.

Plasma proteomic signature of fatty liver disease: The Rotterdam Study.

BACKGROUND AND AIMS: Fatty liver disease (FLD) is caused by excess fat in the liver, and its global prevalence exceeds 33%. The role of protein expression on the pathogenesis of FLD and accompanied fibrosis and its potential as a disease biomarker is currently not clear. Hence, we aimed to identify plasma proteomics associated with FLD and fibrosis using population-based data. APPROACH AND RESULTS: Blood samples were collected from 2578 participants from the population-based Rotterdam Study cohort. The proximity extension assay reliably measured plasma levels of 171 cardiometabolic and inflammatory-related proteins (Olink Proteomics). FLD was assessed by ultrasound, and fibrosis by transient elastography. Logistic regression models quantified the association of plasma proteomics with FLD and fibrosis. In addition, we aimed to validate our results in liver organoids. The cross-sectional analysis identified 27 proteins significantly associated with FLD surpassing the Bonferroni-corrected p <2.92×10 -4 . The strongest association was observed for FGF-21 (ß=0.45, p =1.07×10 -18 ) and carboxylesterase 1 (CES1) protein (ß=0.66, p =4.91×10 -40 ). Importantly, 15 of the 27 proteins significantly associated with FLD were also associated with liver fibrosis. Finally, consistent with plasma proteomic profiling, we found the expression levels of IL-18 receptor 1 (IL-18R1) and CES1 to be upregulated in an FLD model of 3-dimensional culture human liver organoids. CONCLUSIONS: Among the general population, several inflammatory and cardiometabolic plasma proteins were associated with FLD and fibrosis. Particularly, plasma levels of FGF-21, IL-18R1, and CES1 were largely dependent on the presence of FLD and fibrosis and may therefore be important in their pathogenesis.

Association Between the Presence of Metabolic Comorbidities and Liver-Related Events in Patients With Chronic Hepatitis B.

BACKGROUND & AIMS: Patients with chronic hepatitis B (CHB) are at increased risk of hepatocellular carcinoma and (liver-related) mortality. In addition to hepatitis B-related factors, metabolic comorbidities may contribute to the progression of fibrosis. Therefore, we studied the association between metabolic comorbidities and adverse clinical outcomes in patients with CHB. METHODS: We conducted a retrospective cohort study of CHB patients attending the Erasmus MC University Medical Center (Rotterdam, The Netherlands) and CHB patients who underwent liver biopsy at the Toronto General Hospital (Toronto, Canada). The presence of metabolic comorbidities (ie, overweight, diabetes mellitus, hypertension, and dyslipidemia) was assessed based on chart review. The primary end point was liver-related events, defined as the first composite of hepatocellular carcinoma, liver transplantation, or liver-related mortality. RESULTS: We analyzed 1850 patients, of whom 926 (50.1%) were overweight, 161 (8.7%) had hypertension, 116 (6.3%) had dyslipidemia, and 82 (4.4%) had diabetes. During a median follow-up period of 7.3 years (interquartile range, 2.9-11.5 y), a total of 111 first events were recorded. Hypertension (hazard ratio [HR], 8.3; 95% CI, 5.5-12.7), diabetes (HR, 5.4; 95% CI, 3.2-9.1), dyslipidemia (HR, 2.8; 95% CI, 1.6-4.8), and overweight (HR, 1.7; 95% CI, 1.1-2.5) were associated with an increased risk for liver-related events. The presence of multiple comorbidities further increased the risk. Findings were consistent for patients with and without cirrhosis, among noncirrhotic hepatitis B e antigen-negative patients with hepatitis B virus DNA less than 2000 IU/mL and in multivariable analysis adjusting for age, sex, ethnicity, hepatitis B e antigen status, hepatitis B virus DNA, use of antiviral therapy, and the presence of cirrhosis. CONCLUSIONS: Metabolic comorbidities in CHB patients are associated with an increased risk for liver-related events, with the highest risk observed in patients with multiple comorbidities. Findings were consistent in various clinically relevant subgroups, underscoring the need for thorough metabolic assessment in patients with CHB.

Metabolic dysfunction-associated fatty liver disease improves detection of high liver stiffness: The Rotterdam Study.

BACKGROUND AND AIMS: Recently metabolic dysfunction-associated fatty liver disease (MAFLD) has been introduced and was defined as hepatic steatosis with either overweight, diabetes, and/or a combination of other metabolic risk factors. We investigated the application of the MAFLD criteria as compared with NAFLD. APPROACH AND RESULTS: We performed a cross-sectional analysis within the Rotterdam Study, a large prospective population-based cohort. Participants who attended the liver ultrasound and transient elastography program between 2009 and 2014 were eligible for inclusion. Subsequently, individuals with viral hepatitis, alcohol intake >60 g/day, missing alcohol data, and/or missing body mass index were excluded. According to their NAFLD and MAFLD status based on metadata and ultrasound, participants were allocated in overlap fatty liver disease (FLD), NAFLD-only, MAFLD-only, or no FLD. Fibrosis was defined as liver stiffness ≥8.0 kPa. In our analysis, 5445 participants were included: 1866 (34.3%) had MAFLD and 1604 (29.5%) [Correction added on December 27, 2021 after first online publication: The preceding fragment was changed from "1623 (29.8%)"] had NAFLD. This resulted in 1547 (28.4%) [Correction added on December 27, 2021 after first online publication: The preceding fragment was changed from "1566 (28.8%)"] individuals with overlap FLD, 319 (5.9%) [Correction added on December 27, 2021 after first online publication: The preceding fragment was changed from "300 (5.5%)"] with MAFLD-only, 57 (1.0%) with NAFLD-only, and 3522 (64.7%) with no FLD. The MAFLD-only group was strongly associated with fibrosis (adjusted OR 5.30 [Correction added on December 27, 2021 after first online publication: The preceding fragment was changed from "OR 5.27"], p < 0.001) and log-transformed liver stiffness (adjusted beta 0.116, p < 0.001), as opposed to the NAFLD-only group, in which no cases of fibrosis were identified and no association with liver stiffness (adjusted beta 0.006, p = 0.90) was found. CONCLUSIONS: FLD is highly prevalent in the general population. However, not the NAFLD-only, but the MAFLD-only group was associated with fibrosis and higher liver stiffness-independent of demographic and lifestyle factors. We believe that using the MAFLD criteria will help improve the identification and treatment of patients with FLD at risk for fibrosis.

Liver stiffness is associated with excess mortality in the general population driven by heart failure: The Rotterdam Study.

BACKGROUND: Elevated liver stiffness reflects hepatic fibrosis but can also be secondary to venous congestion. We aimed to study the association between liver stiffness and mortality in the general population, stratified for heart failure and/or coronary heart disease (CHD). METHODS: We analysed individuals enrolled in the ongoing prospective population-based Rotterdam Study who attended a visit between 2009-2014 that included liver stiffness measurement. Exclusion criteria for the primary analysis were incomplete data on heart failure, unreliable liver stiffness, alcohol abuse and viral hepatitis, leaving 4.153 participants (aged 67.5 ± 8.4 years, 44.2% male) for analysis with a median follow-up of 6.0 (interquartile range: 5.1-7.0) years. Secondary analysis included participants with viral hepatitis, alcohol abuse and/or unreliable measurement. The association between liver stiffness and mortality was assessed using Cox regression. Associations between heart failure, CHD, and echocardiographic characteristics and liver stiffness were quantified with linear regression. RESULTS: Liver stiffness ≥8.0 kPa was associated with mortality (aHR: 1.37, 95%CI: 1.00-1.89). However, this was driven by participants with heart failure (aHR: 2.48, 95%CI: 1.15-5.35), since high liver stiffness was not associated with mortality in participants without heart failure and/or CHD (aHR: 1.07, 95%CI: 0.70-1.64). Results were consistent when individuals with viral hepatitis, alcohol abuse or unreliable liver stiffness measurement were not excluded. Several cardiovascular characteristics were significantly associated with higher liver stiffness, e.g. heart failure, moderate/poor diastolic dysfunction, and right atrium diameter > 4.5 cm. CONCLUSION: In our cohort of community-dwelling elderly, high liver stiffness was associated with excess mortality, primarily explained by participants with heart failure. Moreover, heart failure and its indicators were associated with increased liver stiffness.

Liver stiffness not fatty liver disease is associated with atrial fibrillation: The Rotterdam study.

BACKGROUND & AIMS: Fatty liver disease has become the most prevalent chronic liver disease globally and is linked to cardiovascular disease, including arrhythmias. However, there have been inconsistent reports on the association between fatty liver disease and atrial fibrillation, while the role of liver stiffness in this association remains unclear. METHODS: Within the Rotterdam Study, a large prospective ongoing cohort, participants attending the abdominal ultrasound program between 2009-2014 were included. Exclusion criteria were no atrial fibrillation data or >20% missing data across analysis variables. Steatosis was assessed by ultrasound, liver stiffness by transient elastography and atrial fibrillation by 12-lead electrocardiograms. Incident atrial fibrillation was based on medical records and complete until 2014. Logistic and Cox-regression were used to quantify associations between fatty liver disease and atrial fibrillation. RESULTS: We included 5,825 participants (aged 69.5±9.1, 42.9% male), 35.7% had steatosis, liver stiffness measurement was available in 73.3%, and 7.0% had prevalent atrial fibrillation. Steatosis was not associated with prevalent atrial fibrillation in fully adjusted models (odds ratio [OR] 0.80; 95% CI 0.62-1.03), findings were consistent for non-alcoholic or metabolic dysfunction-associated fatty liver disease. Liver stiffness was significantly associated with prevalent atrial fibrillation (OR 1.09 per kPa, 95% CI 1.03-1.16); however, this was only persistent among those without steatosis (OR 1.18 per kPa, 95% CI 1.08-1.29). Lastly, no associations were found between steatosis (hazard ratio 0.88; 95% CI 0.59-1.33; follow-up 2.1 [1.1-3.2] years) and incident atrial fibrillation. CONCLUSIONS: Fatty liver disease was not associated with prevalent or incident atrial fibrillation, while liver stiffness was significantly associated with atrial fibrillation, especially among those without steatosis. This association might be driven by venous congestion instead of fibrogenesis, but this awaits further validation. We recommend assessing cardiovascular health in participants with high liver stiffness, especially in the absence of overt liver disease. CLINICAL TRIAL NUMBER: NTR6831. LAY SUMMARY: There have been inconsistent reports about the potential links between fatty liver disease and atrial fibrillation (an irregular and often very fast heart rhythm). Herein, we show that liver stiffness (which is a marker of liver fibrosis), but not fatty liver disease, was associated with a higher prevalence of atrial fibrillation. We hypothesis that atrial fibrillation, rather than fibrosis, may be the cause of increased liver stiffness in participants without overt liver disease.

Objectively Measured Physical Activity Is Inversely Associated With Nonalcoholic Fatty Liver Disease: The Rotterdam Study.

INTRODUCTION: The disease burden of nonalcoholic fatty liver disease (NAFLD) increases rapidly, in line with the obesity pandemic. Physical activity has been linked to a lower risk of NAFLD. However, the impact of different intensities of activity and sedentary behavior and whether their effects on NAFLD are explained by metabolic health remain unclear. METHODS: We performed cross-sectional analyses within the population-based Rotterdam Study cohort. Abdominal ultrasound and accelerometry data were collected between 2009 and 2014. NAFLD was defined as hepatic steatosis diagnosed by ultrasound, in the absence of secondary causes for steatosis: viral hepatitis, steatogenic drugs, and excessive alcohol. We categorized accelerometry data into sedentary time and light, moderate, and vigorous physical activities. RESULTS: We included 667 participants (aged 63.3 ± 6.3 years, 53% female individuals), and 34.3% had NAFLD. Total physical activity was associated with lower NAFLD prevalence adjusted for demographic, lifestyle, and socioeconomic factors (odds ratio: 0.958 per 10 min/d, 95% confidence interval [CI]: 0.929-0.986). More intensive physical activity was more strongly associated with lower NAFLD prevalence: odds ratios for light, moderate, and vigorous physical activities were 0.931 (95% CI: 0.882-0.982), 0.891 (95% CI: 0.820-0.967), and 0.740 (95% CI: 0.600-0.906) per 10 min/d, respectively. These associations were explained by metabolic health, particularly homeostatic model assessment of insulin resistance (proportion mediated: 0.59, P < 0.001) and waist circumference (proportion mediated: 1.08, P < 0.001). Beyond this indirect effect, no direct effect could be demonstrated (P = 0.282-0.827). DISCUSSION: Physical activity at each intensity is inversely associated with NAFLD prevalence, with larger effects for higher intensities of physical activity. This association is mediated by better metabolic health, mainly lower insulin resistance and waist circumference. Physical activity should therefore be incorporated into NAFLD disease management and prevention programs.

Systematically comparing epidemiological and clinical features of MAFLD and NAFLD by meta-analysis: Focusing on the non-overlap groups.

BACKGROUND & AIMS: The applicability of the novel metabolic dysfunction associated fatty liver disease (MAFLD) definition has been studied in numerous cohorts and compared to non-alcoholic fatty liver disease (NAFLD). No consensus has been reached on which definition is preferred. Therefore, this meta-analysis aims to compare the epidemiological and clinical features of NAFLD and MAFLD in the general and non-general population. METHODS: We searched Medline, Embase and Web of Science for studies comparing MAFLD to NAFLD. Based on MAFLD and NAFLD status, the following subgroups were investigated for liver health: overlap fatty liver disease (FLD), NAFLD-only and MAFLD-only. Data were pooled using random-effects models. RESULTS: We included 17 studies comprising 9 808 677 individuals. In the general population, MAFLD was present in 33.0% (95% CI 29.7%-36.5%) and NAFLD in 29.1% (95% CI 27.1%-31.1%). Among those with FLD, 4.0% (95% CI 2.4%-6.4%) did not meet the MAFLD criteria but had NAFLD (NAFLD-only) and 15.1% (95% CI 11.5%-19.5%) was exclusively captured by the novel MAFLD definition (MAFLD-only). Notably, this MAFLD-only group was at significantly increased risk for fibrosis (RR 4.2; 95% CI 1.3-12.9) and had higher alanine aminotransferase (mean difference: 8.0 U/L, 95% CI 2.6-13.5) and aspartate aminotransferase (mean difference: 6.4 U/L, 95% CI 3.0-9.7), compared to NAFLD-only. Similar results were obtained among the non-general population. CONCLUSIONS: Metabolic dysfunction associated fatty liver disease and NAFLD are highly prevalent in the general population, with considerable overlap between them. However, compared to NAFLD, significantly more individuals were additionally identified by MAFLD than were missed. Importantly, by using the MAFLD criteria, more individuals with liver damage were identified. Therefore, the novel MAFLD definition is superior to NAFLD on a population level.

LiverScreen project: study protocol for screening for liver fibrosis in the general population in European countries.

BACKGROUND: The development of liver cirrhosis is usually an asymptomatic process until late stages when complications occur. The potential reversibility of the disease is dependent on early diagnosis of liver fibrosis and timely targeted treatment. Recently, the use of non-invasive tools has been suggested for screening of liver fibrosis, especially in subjects with risk factors for chronic liver disease. Nevertheless, large population-based studies with cost-effectiveness analyses are still lacking to support the widespread use of such tools. The aim of this study is to investigate whether non-invasive liver stiffness measurement in the general population is useful to identify subjects with asymptomatic, advanced chronic liver disease. METHODS: This study aims to include 30,000 subjects from eight European countries. Subjects from the general population aged ≥ 40 years without known liver disease will be invited to participate in the study either through phone calls/letters or through their primary care center. In the first study visit, subjects will undergo bloodwork as well as hepatic fat quantification and liver stiffness measurement (LSM) by vibration-controlled transient elastography. If LSM is ≥ 8 kPa and/or if ALT levels are ≥1.5 x upper limit of normal, subjects will be referred to hospital for further evaluation and consideration of liver biopsy. The primary outcome is the percentage of subjects with LSM ≥ 8kPa. In addition, a health economic evaluation will be performed to assess the cost-effectiveness and budget impact of such an intervention. The project is funded by the European Commission H2020 program. DISCUSSION: This study comes at an especially important time, as the burden of chronic liver diseases is expected to increase in the coming years. There is consequently an urgent need to change our current approach, from diagnosing the disease late when the impact of interventions may be limited to diagnosing the disease earlier, when the patient is asymptomatic and free of complications, and the disease potentially reversible. Ultimately, the LiverScreen study will serve as a basis from which diagnostic pathways can be developed and adapted to the specific socio-economic and healthcare conditions in each country. TRIAL REGISTRATION: This study is registered on Clinicaltrials.gov ( NCT03789825 ).