MED Tesis doctorado

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Browsing MED Tesis doctorado by Author "Barrera Martínez, Francisco"

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    Non-invasive diagnostic for steatotic liver disease: a proposal for primary health care
    (2025) Spencer Sandino, María de los Ángeles; Ferreccio Readi, Catterina; Barrera Martínez, Francisco; Pontificia Universidad Católica de Chile. Escuela de Medicina
    Steatotic Liver Disease (SLD), formerly known as “fatty liver,” is the most common chronic liver condition worldwide, capable of progressing silently from simple steatosis to fibrosis, cirrhosis, and hepatocellular carcinoma. In June 2023, an international consensus led by Rinella et al. redefined this spectrum under the umbrella term SLD, with subcategories including MASLD (Metabolic Dysfunction Associated Steatotic Liver Disease), MetALD (Metabolic Dysfunction Associated Alcohol Related Liver Disease), ALD (Alcohol Related Liver Disease), Specific aetiologies, and cryptogenic. MASLD, driven by obesity, type 2 diabetes, and hypertension, now affects roughly one quarter of adults globally, and in Chile, its prevalence more than doubled from about 23 % in 2000 to nearly 48 % in 2019, mirroring national increases in metabolic risk factors. Because MASLD and related phenotypes are often clinically silent until advanced stages, late diagnosis incurs higher healthcare costs, delays treatment, and worsens outcomes. Lifestyle modification, diet, exercise, and weight loss remain the cornerstone of early management but are increasingly ineffective as fibrosis advances. In the absence of systematic screening programs in Chile’s primary healthcare system, many at-risk individuals go unidentified until complications arise. To address this, the thesis developed and validated non-invasive diagnostic strategies tailored for resource-limited primary care settings, decentralizing detection and enabling timely intervention. Using two large cohorts—the rural Maule Cohort (MAUCO) of 9,013 adults aged 40–74 and the Chile Biliary Longitudinal Study (Chile BiLS) of over 4,338 women with gallstone disease—the work first showed that applying the new SLD classification identifies additional high risk individuals missed by NAFLD and MAFLD criteria, uncovering metabolic profiles linked to elevated fibrosis and cardiovascular risk. Standardized ultrasound readings in Chile BiLS, supported by rigorous training protocols, achieved substantial intra-observer consistency and acceptable inter-observer agreement, demonstrating that point of care ultrasound can reliably serve as a first-line screening tool. Finally, in a nested MAUCO+ trial of 456 high-risk participants, two logistic regression models were developed—one based solely on anthropometry and routine laboratory tests (age, sex, BMI, waist circumference, lipids, insulin, CRP, and ALT) and another incorporating ultrasound. Both models outperformed the Fatty Liver Index: the non-imaging model achieved 81 % sensitivity and 71 % specificity (AUC = 0.79), while the imaging-enhanced model reached 92 % sensitivity and 71 % specificity (AUC = 0.88). By demonstrating that the SLD framework more inclusively identifies those at risk, that ultrasound can be reliably deployed in primary care, and that simple predictive algorithms yield high diagnostic accuracy, this thesis offers a practical roadmap for integrating SLD screening into Chile’s health system. Decentralized, algorithm-driven detection can facilitate early lifestyle interventions, slow disease progression, optimize resource allocation, and ultimately reduce liver-related morbidity and mortality, supporting policy shifts toward nationwide screening initiatives and serving as a model for other Latin American countries facing rising metabolic and hepatic disease.