Obesity represents a risk factor associated with a worse prognosis in patients with COVID-19. Metabolic surgery for weight reduction leads to improvements in health and wellbeing and could therefore result in a better outcome among those who become infected with COVID-19.
The precise reasons why obesity enhances the risk of a more severe outcome in COVID-19 remains unclear. Nevertheless, obesity is associated with several other additional risk factors such as cardiometabolic, thromboembolic and pulmonary disease and it is likely that it is this combination of factors that raises the overall risk. For example, obese patients have higher levels of pro-inflammatory cytokines and oxidative stress which can impact on both the innate and adaptive immune system, all of which may contribute to a worse prognosis. Metabolic surgery in obese patients leads to improvements in cardiovascular risk factors and the amelioration of the pro-inflammatory state linked with obesity.
In a retrospective study of patients testing positive for COVID-19, researchers from the Bariatric and Metabolic Institute, Department of General Surgery, Cleveland Clinic, Ohio, US, set out to examine the relationship between prior metabolic surgery and the severity of COVID-19 in severely obese patients. A total of 33 individuals who had prior metabolic surgery (the surgical group) were identified and were matched 1:10 to non-surgical patients to create a cohort with a body mass index (BMI) greater than or equal to 40kg/m2 at the time of testing. The pre-specified endpoints examined were: admission to intensive care, need for mechanical ventilation, dialysis during their hospital stay and mortality.
Data on a total of 363 patients, including the 33 who had prior metabolic surgery were available for analysis. The surgical group had a mean age of 46.1 years (78% female) with a mean BMI of 37.2±7.1 compared to 46.7± 6.4kg/m2 in the control group. A subsequent univariate analysis showed that 18.2% of those in the surgery group and 42.1% in the control group were admitted to hospital because of their infection with COVID-19. A prior history of metabolic surgery was associated with a statistically lower odds of being admitted to hospital (odds ratio = 0.31, 95% CI 0.11 – 0.88, p = 0.028). Furthermore, none of the surgical group patients experienced one of the four pre-specified endpoints. In contrast, 13% of those in the control group were admitted to intensive care, 6.7% required mechanical ventilation, 1.5% dialysis and 2.4% died. The authors suggested that prior metabolic surgery was associated with a lower severity of COVID-19 infection but recognised that these observations were based on a small sample size and they were also unable to account for their findings.
They concluded by calling for more research to understand the mechanistic role of both obesity and intentional weight loss on COVID-19 infection.
Aminian A et al. Association of prior metabolic and bariatric surgery with severity of coronavirus disease 2019 (COVID-19) in patients with obesity. Surg Obes Relat Dis 2020. https://doi.org/10.1016/j.soard.2020.10.026