Question: What are the risk factors associated with severe COVID-19 outcomes and how does obesity fit into the picture?
Answer: As time goes by, we have more and more information about risk factors related to severe outcomes. Just a few days ago, CDC issued a report that provides US-specific information. This report examined the characteristics of 1,482 patients hospitalized with COVID-19 in 14 states during the month of March. Of the hospitalized patients, 75% were aged 50+ and 55% were male. Unfortunately, data on underlying conditions were available for only 178 (12%) of these patients. That’s a big limitation — we don’t know how representative these patients are among all 1,482 hospitalized. Nevertheless, among these 178 patients, 89% had one or more underlying conditions — the most common were hypertension (50%), obesity (48%), chronic lung disease (35%), diabetes (28%), and cardiovascular disease (28%). The authors state, “These findings suggest that older adults have elevated rates of COVID-19–associated hospitalization and the majority of persons hospitalized with COVID-19 have underlying medical conditions.” These US-based findings largely align with other findings out of China, with the exception that the China studies did not, to my knowledge, explore obesity.
On the obesity question, let’s turn to a study from France that was also published a few days ago. The study examined the relationship between obesity and the severe outcome — mechanical ventilation — among 124 consecutive COVID-19 patients admitted in intensive care in a single French center. Researchers found that obesity was strongly associated with the need for mechanical ventilation regardless of age, diabetes, and hypertension. ICU patients with BMI >35 kg/m2 (severe obesity) were 7x more likely to need mechanical ventilation compared with ICU patients with with BMI <25 kg/m2 (normal weight). The authors concluded, “Obesity is a risk factor for SARS-CoV-2 severity requiring increased attention to preventive measures in susceptible individuals.” As shown in both the CDC and French studies, initial data suggest that obesity is an independent risk factor for severe COVID-19 outcomes. But, given the small size of both studies, more research is needed, including research to understand the biological mechanisms behind the observed relationship.
On a related note, the NY Times article you cite in your question included interesting observations from NY doctors that placing patients on their sides may help with oxygenation and reduce the need for mechanical ventilation. It would be great to have more science to back up this observation. In the meantime, it does align with ways that people with COPD are taught to reduce shortness of breath (described in Q&A of 4/9).