Study finds 'encouraging' recovery of lung capacity, tissue in most severe COVID-19 cases

·4 min read

Despite the havoc that the novel coronavirus wreaks on the brain, heart, and other organ systems of the body, it's important to remember that COVID-19 is primarily a respiratory disease that affects the lungs.

Studies since the beginning of the coronavirus pandemic have shown that even mild COVID-19 can have a severe and lasting impact on the lungs. The prognosis for COVID-19 patients who have had to shift to the intensive care unit (ICU) is believed to be even worse.

Research shows that patients with severe COVID-19 who have to be intubated in the ICU have worse lung damage and are more likely to develop pneumonia and suffer from acute respiratory distress syndrome (ARDS).

A study published in Science Translational Medicine even suggests that critically-ill COVID-19 patients who are given high-flow oxygen from ventilators have a high risk of developing bacterial infections (like Staphylococcus aureus), which can also cause lung abscesses and injuries. All of these factors, when combined, make recovery from COVID-19 more strenuous and, by current estimates, lengthy.

A new study published in Clinical Infectious Diseases suggests that despite all these challenges, the lung tissue of patients who suffered from severe COVID-19 disease €" even those who needed to visit the ICU €" shows good signs of recovery in most cases.

A comprehensive health assessment for COVID-19 survivors

The researchers behind this study wanted primarily to assess the long-term effects of COVID-19 disease and how speedy the recovery is in the case of patients with different degrees of the disease.

To do this, they recruited patients discharged after having COVID-19 disease from the Radboud University Medical Centre, Nijmegen, The Netherlands. These patients had been discharged at least three months prior to the start of the study and were invited to a multidisciplinary outpatient facility. Additionally, patients who had mild COVID-19 disease with symptoms persisting for more than six weeks but had not been required to get admitted to the hospital were also recruited after referrals from general practitioners.

In all, 124 patients were included in the study, 60 percent of whom were male and with an average age of 59 years. Of the 124 subjects, 27 had mild COVID-19, 51 had moderate disease, 26 had a severe infection and 20 had critical disease. All the patients underwent a standardised and comprehensive health assessment which included measurements of lung function, chest CT scan, X-rays, a six-minute walking test, body composition tests, and questionnaires on mental and cognitive health status as well as their quality of life.

Lung capacity and other markers of recovering COVID-19 patients

The researchers found that among 42 percent of the discharged patients, lung diffusion capacity was below the lower limit of normal. The ground-glass opacity (an area of the lung with more attenuation or reduced capacity) showed that 99 percent of discharged patients and 93 percent of patients with mild disease had reduced lung capacity €" suggesting that those who weren't hospitalised had roughly similar lung recovery rates as those who had had severe or critical COVID-19 disease.

Among the discharged patients, 91 percent had residual pulmonary parenchymal abnormalities, 22 percent had low exercise capacity, 19 percent had low fat-free body mass index (BMI) and 36 percent had problems with mental and cognitive function. Almost all patients suffered from fatigue, shortness of breath, functional impairment, and lower quality of life.

While this comprehensive health assessment three months after discharge reveals all the major health problems faced by patients who had severe or critical COVID-19 disease, the researchers came to the conclusion that the level of lung recovery made by most of the patients is promising.

The researchers believe that the patterns of recovery observed in all the above measurements is similar to the recovery trajectory of patients suffering from acute pneumonia or ARDS €" both conditions where fluid accumulates in the lungs and so, the lungs take longer to clear it off and repair the tissues.

Even though recovery from all of these severe respiratory conditions takes a long time, the researchers find the current recovery rate of COVID-19 patients encouraging. They also suggest that more follow-up studies should be conducted globally to determine the precise recovery trajectory of COVID-19 disease.

For more information, read our article on Can COVID-19 cause permanent lung damage?

Health articles in Firstpost are written by, India's first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.

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