Routine respiratory followup important in recovered COVID-19 pneumonia patients: Lancet

Over 100 million people over the world seem to have recovered from COVID-19 infection but concerns remain about long-term sequelae following acute infection. SARS resulted in significant effects on pulmonary function, chronic musculoskeletal pain, and long-term mental disorders in survivors. In this regard researchers explored the temporal trends in respiratory outcomes over 12 months in patients hospitalized for severe COVID-19.

The authors found that in most patients who recovered from severe COVID-19, dyspnea scores and exercise capacity improved over time; however, in a subgroup of patients at 12 months follow-up there was evidence of persistent physiological and radiographic changes. The findings of the study were published in The Lancet Respiratory Medicine journal.

In this prospective longitudinal cohort study, a total of 83 (61%) out of 135 eligible patients admitted to Renmin hospital,Wuhan,China for severe COVID-19 disease who did not require mechanical ventilation were prospectively followed up at 3,6,9 and 12 months post-discharge. Patients with diabetes, hypertension, previous cardiovascular disease, asthma ,COPD and history of smoking were excluded. During follow-up patients were examined and assessed for pulmonary function tests(DLCO,FVC,FEV1,residual volume, vital capacity, TLC),HRCT and 6-min walk test.

Key findings of the study are-

-There was a significant reduction in DLCO over the study period, with a median of 77% of predicted (IQR 67–87) at 3 months, 76% of predicted (68–90) at 6 months, and 88% of predicted (78–101) at 12 months after discharge.

-Multivariate logistic regression showed increasing odds of impaired DLCO associated with female sex (odds ratio 8•61 [95% CI 2•83–26•2]; p=0•0002) independent of age and peak HRCT scores.

-Researchers also found that median 6MWD test increased significantly, from 535 m (IQR 490–565) at 3 months to 585 m (552–626) at 6 months which was statistically significant(p<0•0001).

-The study noted a significant difference in pulmonary function test parameters (including DLCO, functional residual capacity, FVC, residual volume, total lung capacity, and vital capacity) between patients with normal versus abnormal HRCT follow-up scores at 12 months after discharge.

-Peak HRCT pneumonia score during hospitalisation was identified (OR 1•36 [95% CI 1•13–1•62; p=0•0009) as an independent risk factor of abnormal HRCT at 12 months after discharge(OR 1•36 [95% CI 1•13–1•62]; p=0•0009).

Although exercise capacity was found to be improving in most of the patients, reduction in gas transfer was observed in a third of patients. Low DLCO could be the consequence of interstitial abnormalities or pulmonary vascular abnormalities caused by COVID-19 infection.

At 12 months after discharge, 24% of patients had residual radiological changes that were consistent with evolving fibrosis with the presence of interstitial thickening and reticular opacity. None of the HRCT scans showed any development of definitive fibrosis nor progressive interstitial change.

The findings of the current study are consistent with previous reports of 6-months follow-up post discharge but this is the first study to report 12 month outcomes.

Authors conclude-" Our findings highlight the importance of respiratory follow-up of patients with COVID-19, and that further studies to mitigate the long-term consequences of COVID-19 pneumonia, including pulmonary rehabilitation interventions as well as novel therapeutic approaches, are required".

Source:The Lancet Respiratory medicine.