Persistent pulmonary impairment after 2 years of COVID-19 infection: An observational study.

Background: Persistent dyspnoea and pulmonary function impairment are common after coronavirus disease 2019 (COVID-19). However, long-term outcomes beyond 2 years of infection are unknown.

Methods: In this single-center study, we observed the trend of self-reported dyspnoea and pulmonary functions among subjects attending a post-COVID clinic in India after 2 years of COVID-19 illness. Using logistic regression, we explored the clinico-demographic factors associated with persistent dyspnoea and impaired lung functions beyond 2 years.

Results: Among 231 included subjects (68.8% male) with a mean [standard deviation (SD)] age of 44.8 (13.2) years, 119 (51.5%) had recovered from moderate-to-severe COVID-19. The median [inter-quartile range (IQR)] time intervals from COVID-19 diagnosis (T0) to clinical enrolment (T1) and final follow-up (T2) were 3.3 (1.9-5.5) months and 29.5 (27.2-32.2) months, respectively. Between T1 and T2, the prevalence of self-reported dyspnoea remained stable in the whole cohort (39.4% vs. 36.4%, P = 0.26) but declined in the sub-group with moderate-to-severe COVID-19 (63% vs. 54.6%, P = 0.03). Persistent dyspnoea at T2 was associated with female sex (P = 0.007), moderate-to-severe COVID-19 (P < 0.001), and infection during the delta wave (P < 0.001). At T2, impairment in forced vital capacity (FVC) was seen in 48.1% subjects. Persistently impaired FVC was associated with older age (P value = 0.047), female sex (P value <0.001), and infection during the delta wave (P value = 0.02).

Conclusion: Persistent self-reported dyspnoea and impaired pulmonary functions were common in COVID-19 survivors beyond 2 years of infection. Female sex and infection during the delta wave were associated with long-term impairments.