Influencia de la obesidad en la evolución de la infección por SARS-CoV-2 en pacientes con enfermedad renal crónica avanzada en hemodiálisis

Résumé

Background/Objectives The World Health Organization defines obesity as an abnormal or excessive accumulation of body fat that may be harmful to health. 22 In the general population, the most commonly used and easily calculable parameter for diagnosing obesity and cardiovascular risk (diabetes mellitus, hypertension, among others) is the body mass index, defined as weight (kg)/height (m)². However, its applicability in dialysis patients has been questioned in various publications. There are observational studies that have linked an increase in body mass index with higher survival rates in this patient group. This phenomenon, called "the obesity paradox," has led to numerous publications attempting to explain the potential advantages of obesity. In chronic kidney disease, there is a significant chronic inflammatory burden that leads to important bodily changes, such as gradual weight loss and a high risk of malnutrition. The adipose tissue continues to generate mediators associated with metabolic and inflammatory pathways. Therefore, the body mass index may not be a precise indicator of obesity in these patients; thus, having devices like bioimpedance for measuring body composition, which estimates lean mass, fat mass, and hydration, provides more reliable information on the true relationship between obesity and mortality in dialysis patients. When obesity and COVID-19 are related, it represents significant challenges for global public health. Obesity is a global epidemic associated with an increased risk of chronic diseases, including chronic kidney disease. On the other hand, COVID-19 has generated an unprecedented health crisis, impacting millions of people worldwide, especially affecting vulnerable and multimorbid populations such as dialysis patients. In the context of hemodialysis, a vital treatment for patients with chronic kidney disease, the question arises about how obesity influences the course of COVID-19. The aim is to describe the nutritional characteristics and their potential association with the prognosis of COVID-19 in patients on chronic hemodialysis treatment. 23 Materials and Methods A descriptive retrospective observational study was conducted with patients undergoing chronic hemodialysis treatment from the onset of the pandemic until before vaccination. Results During the study period (March 2020 to April 2021), a 12% (patients 22) incidence of SARS-CoV-2 infection was observed among the 189 patients receiving chronic hemodialysis treatment. The average age of the patients was 71 years, with an average Charlson index of 6.59 points. Ten patients were female, and a history of diabetes mellitus was recorded in 10 cases. The average duration of classic hemodialysis was 51.6 months, with two patients having previously undergone a non-functioning kidney transplant. Most patients had arteriovenous fistulae (16 cases), while six had central vascular access. The average dialysis session time was 220.14 minutes, and the initial single dose of Kt/V pool was recorded at 1.7. Body composition measurement was performed in 16 patients. When analyzing differences between deceased and surviving patient groups, significant discrepancies were observed in serum levels of triglycerides and ferritin (p < 0.05), suggesting a possible association between these markers and the clinical outcome of patients. Furthermore, a strong association (p <0.05) was identified between mortality and body mass index, as well as between mortality and fat tissue index. Conclusions Obesity is shown to be a significant risk factor in the evolution of SARS-CoV-2 infection in hemodialysis patients, showing an elevation with higher rates of mortality, which may have important clinical and public health implications. 24 The relationship of a higher body mass index, higher body fat content, low basal levels of triglycerides and ferritin would be the factors most related to mortality in this group. These findings suggest that the initial nutritional status of these patients can significantly influence the prognosis of SARSCoV-2 infection. Additional studies are required to better understand the underlying biological mechanisms connecting obesity, compromised kidney function, and the progression of SARS-CoV-2 infection, which could guide future therapeutic strategies.