Indians more hit by long-term lung damage after Covid: Study

New Delhi: A significant proportion of Indians who recovered from Covid had lung function impairment and lingering symptoms for months, a study published by Christian Medical College, Vellore, has revealed.

It found Indians had more lung function damage when compared to Europeans and the Chinese. While gradual return to normalcy may occur over up to one year in some, others may have to live with lung damage for life, it stated.

The study, touted as the country’s largest to investigate SARS-CoV-2’s impact on lung function, examined 207 individuals. Conducted during the first wave of the pandemic, this study was recently published in the PLOS Global Public Health journal.

After over two months of recovery, complete lung function tests, six-minute walk test, blood tests and quality of life assessments were carried out for these patients who suffered mild, moderate and severe Covid.

The most sensitive lung function test namely gas transfer (DLCO), which measurers the ability to transfer oxygen from the air breathed to the bloodstream, was affected in 44%, which CMC doctors called “very worrying”; 35% exhibited a restrictive lung defect, which would affect the ability of the lung to inflate with air as they breathe and 8.3% had an obstructive lung defect, which would affect the ease with which air could move in and out of the lungs. Quality of life tests also demonstrated an adverse impact.

“In all aspects, Indian patients fared worse,” the principal investigator of the study, Dr D J Christopher, professor, department of pulmonary medicine, CMC, Vellore, told TOI. Additionally, more Indian subjects had comorbidities like diabetes and hypertension compared to Chinese and European subjects.

According to Dr Salil Bendre, head of pulmonology at Nanavati Hospital, a subset of Covid patients who experienced moderate to severe infection, requiring hospitalization approximately 8-10 days after onset, oxygen support and steroid treatment went on to develop post-infection lung fibrosis. “About 95% of these patients gradually clear lung damage, leaving 4-5% with permanent impairment in the long run,” he said.