Loss of muscle mass in the acute phase of Covid is associated with persistent symptoms, study shows

The greater the loss of muscle mass during the period of hospitalization for Covid-19, the greater the chances of the patient developing persistent symptoms of the disease, such as muscle impairment and the so-called long Covid, which can include difficulty breathing, persistent cough, pain headaches, insomnia and anxiety.

The conclusion is from a study conducted at the Faculty of Medicine of USP (University of São Paulo) and published in the Journal of the American Medical Directors Association. The results also indicate that there is a relationship between greater loss of muscle mass and higher health expenses in the months following hospital discharge.

“The loss of muscle mass is fairly common during prolonged periods of hospitalization. However, this condition seems to be exacerbated in patients hospitalized by Covid, affecting muscle mass, strength and function to the point of compromising the patient’s mobility in some cases”, explains Hamilton Roschel, leader of the study and one of the coordinators of the research group in applied physiology and nutrition at the School of Physical Education and the Faculty of Medicine at USP.

Funded by Fapesp through two projects (17/13552-2 and 20/08091-9), the investigation involved 80 patients with moderate or severe Covid-19 hospitalized at the Hospital das Clínicas of FM-USP in 2020 —a time when there were no vaccines available. The participants were followed during and after the hospitalization period.

The researchers measured the patients’ strength and muscle mass at four time points: as soon as they were admitted to the hospital, when they were discharged, and two and six months after they were discharged from the hospital. For this purpose, equipment (dynamometer) was used to measure handgrip strength —a measure that has a good correlation with an individual’s global strength. Muscle mass was measured using an ultrasound device, using the thigh muscle as a reference.

“It is common to associate muscle function only with locomotion, but the musculoskeletal system has a much broader role. It participates in several other processes in the organism, such as the regulation of metabolism and even the immune system”, explains Roschel.

According to the analyses, in patients who had greater loss of muscle mass, there was also a higher prevalence of fatigue (76%) and muscle pain (66%). In those who had less musculature impairment, the prevalence was, respectively, 46% and 36%.

In the evaluation carried out six months after hospital discharge, those who had lost more muscle mass still had difficulty recovering their previous muscles. Those who had little loss recovered almost completely in the period.

prognostic predictor

The researchers also assessed health expenditures during the six months following hospital discharge.

“Although there were no major differences in relation to rehospitalization and self-perception of health, patients who lost more muscle mass had a much higher total cost with health related to Covid-19 than the other group”, says Roschel.

On average, participants whose muscles were most affected in the acute phase spent US$77,000 against US$3,000 in the first two months after hospital discharge. When considering the six months after leaving the hospital, this amount was approximately US$ 90,000 spent on rehabilitation and other complications, against US$ 12,000 on average for those with less muscle impairment.

“The results show that the loss of muscle mass seems to be a negative prognostic parameter in hospitalized patients, which suggests that testing of therapeutic interventions is necessary already during the hospitalization period. At the collective level, of public health, we show that the loss of Muscle mass is associated with higher costs, which certainly impacts and puts pressure on health systems, not only in the economic sphere, but also in the demand for rehabilitation services for these patients”, he evaluates.

A previous study by the group had shown that measures of strength and muscle mass can help predict the length of stay for Covid-19. When analyzing these data at the time of hospital admission, it was possible to observe that patients with better muscle health tended to remain hospitalized for less time.

“This first stage of the work showed how Covid-19 affects the muscle and the importance of having a ‘previous muscle reserve’ to deal with the infection. Now we see that, six months after hospital discharge, those who lost more mass not only did not managed to recover it as it had more persistent symptoms and higher health expenses. It is important to emphasize the impact of the disease also on the musculoskeletal system and how this requires attention from the health systems, even after the patient has recovered from the infection”, emphasizes the author .