Muscle strength and mass may help predict length of hospital stay

A study conducted by researchers at USP evaluated 186 individuals hospitalized with moderate or severe COVID-19 and found that those who had more strength and muscle mass tended to remain hospitalized for a shorter period of time. The results, therefore, suggest that these indicators can help predict the length of hospital stay due to the disease.

“They can be useful for preventive work with individuals at higher risk of worsening, while also indicating where there will be a possible need for attention in the management of survivors with COVID-19 sequelae. This means making individuals with less muscle mass and strength, and therefore more vulnerable, more likely to face potential hospitalization. The lower the strength and muscle mass, the greater the chance of the individual having complications. This can be generalized to a series of conditions, and now we have shown that it is potentially valid for COVID-19 as well,” says Hamilton Roschel, author of the study and one of the coordinators of the Applied Physiology and Nutrition Research Group at the School of Physical Education and Sports (EEFE) and the School of Medicine (FMUSP).

The complete data from the study, which was supported by the São Paulo Research Foundation (Fapesp), were published on the medRxiv platform, in an article that has not yet been peer-reviewed.

“The lower the muscle strength and mass, the greater the chance that the individual will have complications. This can be generalized to a series of conditions, and we have now shown that it is potentially valid for COVID-19 as well.”

In the study, the researchers measured the patients’ muscle strength as soon as they were admitted to the hospital, using equipment that measures handgrip strength (a measurement that has a good correlation with overall strength). An ultrasound device was used to measure muscle mass. Based on the image of the muscle, its cross-sectional area was measured.

Of the 186 patients analyzed, those who had more strength and muscle mass tended to remain hospitalized for a shorter period of time – Photo: Health/Government of Tocantins

Aging and chronic conditions, such as type 2 diabetes, are factors that increase the risk of developing severe forms of COVID-19. However, the researchers emphasize, young and apparently healthier individuals may also need to be hospitalized and even die from the disease. “This suggests the existence of as yet unknown clinical characteristics associated with the prognosis of COVID-19. Strength and muscle mass parameters are potential candidates for this,” they say.

Skeletal muscle makes up about 40% of a person's total body mass and plays an important role in different physiological processes, such as immune response, regulation of glucose levels, protein synthesis, and metabolism. Previous studies had already indicated strength and muscle mass as predictors of overall hospitalization time, which was confirmed by the USP researchers also for COVID-19 cases.

“However, we are not suggesting using these measures to the detriment of other biochemical markers already established for the prognosis of the disease, such as saturation and C-reactive protein, among others. Information on muscle mass and strength will be even more important for treating survivors, who may present sequelae,” says Roschel.

Rehabilitation of survivors

The recovery of patients who survived COVID-19 and developed a wide variety of sequelae is a problem that stands out among so many caused by the pandemic. According to experts, the syndemic – as the pandemic of post-COVID syndrome that is being announced has been called – will also represent a major burden on the health system.

Coronavirus: P.1 advance in the territory repeats 2020, with many more cases and deaths

PUBLIC: https://jornal.usp.br/ciencias/forca-e-massa-muscular-podem-ajudar-a-prever-tempo-de-internacao-por-covid-19/

Early rehabilitation in COVID ICUs reduces physical deficits of patients upon hospital discharge

“The most compromised seem to be the patients who stay longer in the hospital. This long stay is associated with a sequence of negative events and this has to be considered from the point of view of the general treatment of the disease. When the number of cases decreases, the issue of rehabilitating these survivors will be the biggest problem we will need to face,” he says.

The group is conducting another study that will analyze how much strength and muscle mass can be affected by hospitalization. “We have patients who lose more than 30 kilos during their time in the hospital and can barely walk after discharge. With this study, it will be possible to analyze to what extent the length of hospitalization compromises the patient's functionality. Based on these results, we will have very important repercussions for rehabilitation. There is already a great demand,” he says.

The article Muscle Strength and Muscle Mass as Predictors of Hospital Length of Stay in Patients with Moderate to Severe Covid-19: A Prospective Observational Study can be read in the journal Medrxiv.