Respiratory risk, not death, increased for adults with obesity in ICU with COVID-19
Obesity is not associated with an increased risk for death for adults admitted to the ICU with COVID-19, but BMI is linked to acute respiratory distress syndrome in these patients, according to a study published in Obesity.
In the Study of the Treatment and Outcomes in Critically Ill Patients with COVID-19 (STOP-COVID), researchers analyzed the records of adults admitted to the ICU with COVID-19 at 68 U.S. hospitals. Although having a higher BMI was associated with a higher risk for acute respiratory distress syndrome and acute kidney injury requiring renal replacement therapy, there was no increased risk for mortality observed.
“The absence of an association between BMI and circulating biomarkers of inflammation and thrombosis challenges their hypothesized links with obesity and adverse outcomes in COVID-19,” Allon N. Friedman, MD, assistant professor of medicine in the division of nephrology at the Indiana University School of Medicine, and colleagues wrote.
Researchers analyzed data from 4,925 consecutive adults (mean age, 60.9 years; 62.8% men; 2,552 with obesity) who tested positive for COVID-19 and were admitted to the ICUs of 68 U.S. hospitals from March 4 to June 30, 2020. Patients were followed until hospital discharge, death or the end of the analysis on Aug. 1, 2020. Demographics, comorbidities, laboratory values, physiologic parameters, medications, treatments, organ support and clinical outcomes were obtained through a detailed chart review. The primary outcome was in-hospital mortality, and secondary outcomes included acute respiratory distress syndrome, acute kidney injury requiring renal replacement therapy and thrombotic events during the first 14 days of ICU admission.
During hospitalization, 39.4% of participants died within a median time of 10 days. In a multivariable model, there was no association between BMI and in-hospital COVID-19 mortality.
Acute respiratory distress syndrome was observed in 72.2% of the study cohort. In an unadjusted model, an increased risk for acute respiratory distress syndrome was observed in people with a BMI of 25 kg/m2 to 29.9 kg/m2 (HR = 1.21; 95% CI, 1.11-1.33), 30 kg/m2 to 34.9 kg/m2 (HR = 1.4; 95% CI, 1.24-1.58), 35 kg/m2 to 39.9 kg/m2 (HR = 1.36; 95% CI, 1.24-1.48) and 40 kg/m2 or more (HR = 1.34; 95% CI, 1.15-1.56). Similar associations were observed in multivariable analysis.
“Some proposed reasons why obesity is an independent risk factor for acute respiratory distress syndrome include increased inflammation, immune system dysfunction, decreased wound healing, accumulation of lipofibroblasts that differentiate into fibrosis-promoting myofibroblasts, and associated restrictive lung disease,” the researchers wrote.
Nineteen percent of the study cohort developed acute kidney injury requiring renal replacement therapy. In multivariable analysis, the risk for acute kidney injury requiring renal replacement was higher in adults with a BMI of 25 kg/m2 to 29.9 kg/m2 (HR = 1.46; 95% CI, 1.1-1.94), 30 kg/m2 to 34.9 kg/m2 (HR = 1.83; 95% CI, 1.37-2.43), 35 kg/m2 to 39.9 kg/m2 (HR = 2.01; 95% CI, 1.44-2.79) and 40 kg/m2 or more (HR = 2.27; 95% CI, 1.56-3.31). Similar associations were observed in multivariable analysis.
Thrombotic events were reported in 11.2% of participants. No associations were found between BMI and a higher risk for thrombosis.
Researchers also analyzed the association between BMI and circulating biomarkers at ICU admission. The only significant association observed was between BMI and serum albumin, with every 10 kg/m2 increase in BMI associated with a 0.1 g/dL increase in albumin.
“Our preliminary findings raise into question the paradigm that obesity contributes to poor outcomes in critically ill patients with COVID-19 at least in part by upregulating systemic inflammatory and prothrombotic pathways,” the researchers wrote. “However, further research in this area is clearly required.”