Marco Antonio Luna-Ruiz-Esparza

Purpose: This study aimed to determine the phenotypic distribution of ABO and Rh blood groups in a geographically diverse cohort of Mexican outpatients. Patients and Methods: A clinic-based, retrospective, cross-sectional study was conducted using anonymized electronic health records (EHRs) from 1,820,793 individuals aged 1 to 100 years who underwent clinically or administratively indicated ABO and Rh blood typing at Salud Digna clinics across all 32 Mexican states between January 2023 and July 2025. All ABO and Rh determinations were performed by forward typing using either the fully automated Galileo Echo immunohematology analyzer or by the conventional slide method using commercial anti-A, anti-B, and anti-D antisera. Demographic and blood group distributions were summarized using descriptive statistical methods, and sex-specific distributions were evaluated. Results: Among the 1,820,793 individuals analyzed (median age: 29 years), 1,193,587 (65.6%) were female and 627,206 (34.4%) were male. Blood group O was the most frequent ABO phenotype (65.99%), whereas group AB was the least common (1.50%). For the Rh system, 3.39% of individuals exhibited the Rh(d) phenotype. The overall phenotypic distribution was as follows: O Rh(D) (64.01%), A Rh(D) (23.24%), B Rh(D) (7.92%), O Rh(d) (1.98%), AB Rh(D) (1.43%), A Rh(d) (1.02%), B Rh(d) (0.32%), and AB Rh(d) (0.07%). Notably, the AB Rh(d) phenotype was not identified in Oaxaca. From a geographical perspective, a clear north-to-south gradient was observed, with increasing frequencies of the O Rh(D) phenotype toward the southern states, accompanied by declining trends observed for the remaining ABO and Rh phenotypes. Conclusion: Blood group O was the most frequent ABO phenotype, whereas the Rh(d) phenotype was relatively uncommon. The overall distribution patterns were largely consistent across the states. These findings provide a valuable resource for health authorities and blood services to support blood inventory management, inform region-specific donor recruitment strategies for less common blood group phenotypes, and optimize planning for blood transfusion services, organ transplantation, and maternal healthcare.

Background/Objectives: Obesity is a chronic, multifactorial condition characterized by excessive adipose tissue that adversely affects health and continues to rise worldwide. It is strongly associated with cardiometabolic abnormalities that increase the risk of adverse outcomes, including type 2 diabetes and coronary heart disease. Methods: We conducted a multicenter, clinic-based cross-sectional analysis of electronic health records from 200,022 adults aged ≥20 years, who accessed nutritional and clinical laboratory services at Salud Digna between 1 January 2022 and 31 December 2025. Nutritional status was classified as normal weight or overweight/obesity using body mass index criteria. Metabolic health was assessed using five components of the National Cholesterol Education Program Adult Treatment Panel III criteria. Individuals were defined as metabolically unhealthy if they met three or more metabolic syndrome criteria. Results: Among participants, 78.17% of males and 79.73% of females were classified as overweight or obese. Metabolic unhealthiness was observed in 50.74% of males and 55.42% of females. The prevalences of metabolically healthy normal weight, metabolically healthy overweight/obesity, metabolically unhealthy normal weight, and metabolically unhealthy overweight/obesity were 18.55%, 31.09%, 3.90%, and 44.20%, respectively. Conclusions: These findings highlight a high burden of overweight/obesity and metabolic abnormalities in a large clinic-based sample of Mexican adults. While not nationally representative, this study provides important insights into the distribution of nutritional and metabolic health profiles in individuals accessing healthcare services, supporting the need for targeted prevention, early detection, and management strategies in clinical settings.

Background/Objectives: Astigmatism is one of the most common refractive errors and represents a risk factor for other ocular conditions, including myopia and amblyopia. In Mexico, comprehensive epidemiological data on refractive astigmatism, particularly its axis-related subtypes, remain limited. This study aimed to estimate the prevalence and distribution of axis subtypes of refractive astigmatism in a nationwide, clinic-based cohort of Mexican outpatients. Methods: We conducted a retrospective, cross-sectional, multicenter study using anonymized electronic health records (EHRs) from Salud Digna clinics across all 32 states of Mexico. Individuals aged 5–90 years who underwent routine non-cycloplegic eye examinations between 2021 and 2023 were included. Refractive astigmatism was defined as a cylinder power (Cyl) of ≤−0.75 D. Age-adjusted prevalence and distribution of axis subtypes (with-the-rule [WTR], against-the-rule [ATR], and oblique [OBL]) were determined according to sex, age groups, and geographic locations. Logistic regression models evaluated potential associations between demographic variables and refractive astigmatism. Results: Data from 8,622,191 individuals were analyzed (median age: 45 years; 63.4% females). The age-standardized prevalence of refractive astigmatism was 41.59% (95% CI: 41.54–41.64%) and was higher in males (45.43%) than females (39.32%). WTR astigmatism predominated among younger individuals, peaking at ages 15–19 (48.97%), whereas ATR astigmatism increased with age, reaching 35.36% among those aged 80–90 years. In multivariable analysis, refractive astigmatism was significantly associated with age, sex, and state of residence, showing a non-linear, non-monotonic age pattern with peaks in adolescence (aOR = 1.47; 95% CI, 1.456–1.484) and older (aOR = 1.177; 95% CI, 1.161–1.193) age, higher odds in males (aOR = 1.269; 95% CI, 1.265–1.272), and marked geographic variability, with the highest in Tlaxcala (aOR = 3.581; 95% CI, 3.491–3.675). Conclusions: Refractive astigmatism was more prevalent in males and showed a clear age-related shift in the axis subtype beginning in the early 40s. These findings provide large-scale, real-world evidence that enhances the understanding of astigmatism epidemiology in Mexico and may inform future research and public health planning.

Background: Refractive errors (REs) and amblyopia are the leading causes of visual impairment (VI) in children worldwide; however, national data for Mexico are scarce. Objective: We aim to estimate the clinical prevalence of RE, refractive amblyopia, and associated visual impairment (VI) in Mexican children aged 6–12 years. Methods: We analyzed 784,372 non-cycloplegic eye examinations from Salud Digna outpatient clinics across all 32 Mexican states (2021–2025). REs were classified as myopia (≤−0.50 D), hyperopia (≥+2.00 D), or astigmatism (≤ −1.00 D cylinder). Refractive amblyopia was defined as best-corrected visual acuity ≤ 20/30 in the most affected eye. The VI categories followed the WHO criteria. Results: Myopia was the most frequent (43.86%), followed by astigmatism (38.41%) and hyperopia (1.29%). Refractive amblyopia affected 4.94% of the children, predominantly due to astigmatic isoametropia (72.19%). VI related to refractive amblyopia occurred in 1.20% (mild), 0.37% (moderate), 0.01% (severe), and 0.01% (blindness) of children. Men showed a higher prevalence of RE and refractive amblyopia (p < 0.01). Geographic disparities were evident, with the central and southern states reporting the highest RA rates. Conclusions: Our outpatient-based study underscores REs, refractive amblyopia, and astigmatic ametropia as significant public health concerns in Mexican school-aged children. The high prevalence of uncorrected REs and refractive amblyopia highlights the need for nationwide school-based screening programs and early intervention strategies to mitigate long-term visual and developmental consequences.

Few reports have shared the workflows to reduce SARS-CoV-2 infections among risk groups, including healthcare workers (HCWs). This study describes an occupational health program implemented to reduce the incidence of COVID-19 and establishes a back-to-work algorithm in HCWs of 129 Salud Digna outpatient care clinics in Mexico. This program was composed of training plans, screening SARS-CoV-2 infections, the containment of infections, follow-up COVID-19 cases, and continuing supervision in addition to the steady supply and training for the correct use of PPE. From 16 April 2020 to 15 April 2021, 7376 individuals were enrolled, of which 423 were excluded because they did not meet the inclusion criteria or refused the follow-up. In the cohort studied, we found a COVID-19 incidence of 35.4% (2610 individuals), lower hospitalization (0.11%), ICU (0.04%) and lethality rate (0.04%). Additionally, 85.9% of COVID-19 cases tested negative for SARS-CoV-2 after 14 days of the first positive test with an average isolation time of 26–33 days. Finally, 99% of people received personal protective equipment and adequate training to use it. Our results show that the program implemented reduced the hospitalization ICU admission and lethality in HCWs; we consider this workflow to help other workplaces offer safe conditions for HCWs and patients.

The SARS-CoV-2 pandemic is one of the most concerning health problems around the globe. We reported the emergence of SARS-CoV-2 variant B.1.1.519 in Mexico City. We reported the effective reproduction number (Rt) of B.1.1.519 and presented evidence of its geographical origin based on phylogenetic analysis. We also studied its evolution via haplotype analysis and identified the most recurrent haplotypes. Finally, we studied the clinical impact of B.1.1.519. The B.1.1.519 variant was predominant between November 2020 and May 2021, reaching 90% of all cases sequenced in February 2021. It is characterized by three amino acid changes in the spike protein: T478K, P681H, and T732A. Its Rt varies between 0.5 and 2.9. Its geographical origin remain to be investigated. Patients infected with variant B.1.1.519 showed a highly significant adjusted odds ratio (aOR) increase of 1.85 over non-B.1.1.519 patients for developing a severe/critical outcome (p = 0.000296, 1.33–2.6 95% CI) and a 2.35-fold increase for hospitalization (p = 0.005, 1.32–4.34 95% CI). The continuous monitoring of this and other variants will be required to control the ongoing pandemic as it evolves.