Lung function decline in relation to COVID-19 in the general population: a matched cohort study with pre-pandemic assessment of lung function

Post-discharge spirometry evaluation in patients recovering from moderate-to-critical COVID-19: a cross-sectional study

Understanding the prevalence of abnormal lung function and its associated factors among patients recovering from COVID-19 is crucial for enhancing post-COVID care strategies. This study primarily aimed to determine the prevalence and types of spirometry abnormalities among post-COVID-19 patients in Malaysia, with a secondary objective of identifying its associated factors. Conducted at the COVID-19 Research Clinic, Faculty of Medicine, University Technology MARA, from March 2021 to December 2022, this study included patients at least three months post-discharge from hospitals following moderate-to-critical COVID-19. Of 408 patients studied, abnormal spirometry was found in 46.8%, with 28.4% exhibiting a restrictive pattern, 17.4% showing preserved ratio impaired spirometry (PRISm), and 1.0% displaying an obstructive pattern. Factors independently associated with abnormal spirometry included consolidation on chest X-ray (OR 8.1, 95% CI 1.75-37.42, p = 0.008), underlying cardiovascular disease (OR 3.5, 95% CI 1.19-10.47, p = 0.023), ground-glass opacity on chest X-ray (OR 2.6, 95% CI 1.52-4.30, p < 0.001), and oxygen desaturation during the 6-min walk test (OR 1.9, 95% CI 1.20-3.06, p = 0.007). This study highlights that patients recovering from moderate-to-critical COVID-19 often exhibit abnormal spirometry, notably a restrictive pattern and PRISm. Routine spirometry screening for high-risk patients is recommended.

Lung Function Trajectories in Mild COVID-19 With 2-year Follow-up

BACKGROUND

The long-term pulmonary sequelae of mild coronavirus disease 2019 (COVID-19) remains unknown. In this study, we aimed to characterize lung function trajectories in individuals with mild COVID-19 from preinfection to 2 years postinfection.

METHODS

We reinvited participants 2 years after infection from our matched cohort study of the Copenhagen General Population who had initially been examined 5.4 months after infection. We repeated lung tests and questionnaires. Linear mixed models were used to estimate dynamics in lung volumes in individuals with COVID-19 patients versus uninfected controls over two intervals: from pre-infection to 6 months postinfection and 6 months postinfection to 2 years postinfection.

RESULTS

52 individuals (48.6%) attended the 2-year examination at median 1.9 years (interquartile range, 1.8-2.4) after COVID-19, all with mild infection. Individuals with COVID-19 had an adjusted excess decline in forced expiratory volume in 1 second (FEV1) of 13.0 mL per year (95% confidence interval [CI], -23.5 to -2.5; P = .02) from before infection to 6 months after infection compared to uninfected controls. From 6 to 24 months after infection, they had an excess decline of 7.5 mL per year (95% CI, -25.6-9.6; P = .40). A similar pattern was observed for forced vital capacity (FVC). Participants had a mean increase in diffusing capacity for carbon monoxide (DLco) of 3.33 (SD 7.97) between the 6- and 24-month examination.

CONCLUSIONS

Our results indicate that mild COVID-19 infection affects lung function at the time of infection with limited recovery 2 years after infection.

Long-term impact of SARS-CoV-2 infection on cardiorespiratory fitness: a meta-analysis

Background

Despite surviving Coronavirus disease 2019 (COVID-19), its long-term impact is of concern. Low cardiorespiratory fitness is a strong predictor of all-cause mortality, and likely affected by multisystem impairments following COVID-19 infection. Accumulating evidence has identified the impact of COVID-19 on cardiorespiratory fitness level. However, the findings have been controversial. Conclusive evidence is still needed.

Objectives

This review aimed to systematically summarize and synthesize whether the SARS-CoV-2 infection diminishes cardiorespiratory fitness in COVID-19 survivors.

Design

The study design was a systematic review and meta-analysis.

Methods

A search was carried out using PubMed, CINAHL, Scopus, Embase and the Cochrane Library, together with reference lists (searching from their inception to January 2023). Observational studies investigating the impact of COVID-19 on outcomes relevant to cardiorespiratory fitness (i.e., peak oxygen uptake) were included. Weighted mean difference (WMD) and 95% confidence interval (CI) were used to identify a pooled effect estimate. Use of a random effects model was considered as the main method. Grading of Recommendation Assessment, Development and Evaluation approach was employed to determine the certainty of evidence. This meta-analysis was registered with PROSPERO (registration number: CRD42023393108).

Results

Seven eligible studies (4 cross-sectional, 2 cohort, and 1 case-control studies) involving 4,773 participants were included in this meta-analysis. A pooled effect estimates showed that patients in the surviving COVID-19 group had a significant reduction in peak oxygen uptake when compared to their counterparts in the non-COVID-19 group (WMD -6.70, 95%CI -9.34 to -4.06, low certainty). A subgroup analysis by age found that COVID-19 survivors in the young- to middle-aged and middle- to older-aged subgroups had significant reductions in peak oxygen uptake when compared to their counterparts in the non-COVID-19 group (WMD -5.31, 95%CI -7.69 to -2.94, low certainty; WMD -15.63, 95%CI -28.50 to -2.75, very low certainty, respectively). Subgroup analyses by symptom found that patients with moderate to severe symptoms in the surviving COVID-19 group had significantly lower peak oxygen uptake than their counterparts in the non-COVID-19 group (WMD -15.63, 95%CI -28.50 to -2.75, very low certainty).

Conclusion

The current meta-analysis concluded that patients in the COVID-19 survivors had poorer cardiorespiratory fitness than their counterparts in the non-COVID-19 group, but there is considerable uncertainty of evidence. Poorer cardiorespiratory fitness is likely to be more pronounced in COVID-19 survivors who are getting older and had severe symptoms, but it is uncertain whether such finding has a valuable in clinical context.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, CRD42023393108.

Lung-function trajectories in COVID-19 survivors after discharge: A two-year longitudinal cohort study

Background

Data on the long-term trajectories of lung function are scarce in COVID-19 survivors.

Methods

We re-analyzed the data from a prospective longitudinal cohort follow-up study of COVID-19 survivors over 2 years after infection. All participants were divided into scale 3, scale 4 and scale 5-6 groups according to seven-category ordinal scale. The changes of pulmonary function tests (PFTs), the Modified Medical Research Council (mMRC) Dyspnea Scale, 6-min walking test health-related quality of life (HRQoL) across the three serial follow-up visits were evaluated, and compared among three groups. We performed liner regression to determine potential factors that were associated with changes of PFTs and distance walked in 6 minutes (6MWD).

Findings

In this study, 288 participants generally presented an improvement of PFTs parameters from 6 months to 1 year after infection. The scale 5-6 group displayed a significantly higher increase of PFTs compared with scale 3 and scale 4 groups (all p<0.0167), and corticosteroids therapy was identified as a protective factor for the PFTs improvement with a correlation coefficient of 2.730 (0.215-5.246) for forced vital capacity (FVC), 2.909 (0.383-5.436) for total lung capacity (TLC), and 3.299 (0.211-6.387) for diffusion capacity for carbon monoxide (DLco), respectively. From 1-year to 2-year follow-up, the PFTs parameters generally decreased, which was not observed to be associated with changes of 6MWD and HRQoL. Dyspnea (mMRC≥1) generally decreased over time (23.3% [61/262] for 6-month, 27.9% [67/240] for 1-year, 13.4% [35/261] for 2-year), and 6MWD increased continuously (500.0 m vs 505.0 m vs 525.0 m).

Interpretation

Corticosteroids therapy during hospitalization was a protective factor for PFTs improvement from 6 months to 1 year. The relatively fast decline trend of PFTs from 1 year to 2 years needs to be paid attention and further validated in the future follow-up study.

Fundings

This work was supported by Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (CIFMS 2021-I2M-1-048) and the National Key Research and Development Program of China (2021YFC0864700).

Interstitial lung disease following coronavirus disease 2019

PURPOSE OF REVIEW

The aim of this review was to summarize the recent data concerning interstitial lung disease after COVID-19, a field where knowledge is evolving very quickly.

RECENT FINDINGS

It has been found that a proportion of patients displayed fibrotic-like pattern on chest computed tomography shortly after COVID-19 pneumonia. Those lesions can potentially represent precursors of fibrosis, although most of them will resolve until 1 year postinfection. There was a wide range of the prevalence of post-COVID-19 interstitial lung disease detected in the literature, which can be attributed to the heterogeneous definition of lung abnormalities and the discrepancy of study design. The severity of acute COVID-19 disease has been linked to increased risk of residual imaging and functional abnormalities, while reduced DLco was the most common functional abnormality in long-term survivors. Studies indicated that pathophysiology of post-COVID interstitial lung disease shares common mechanisms with idiopathic pulmonary fibrosis. Regarding therapeutic strategies of post-COVID-19 interstitial lung disease, the role of immunosuppressive and antifibrotic treatment is currently under investigation.

SUMMARY

We still need to learn about the natural history of COVID-19 disease, allowing for a better targeting of therapeutic interventions through a multidisciplinary approach.

Restrictive spirometry versus restrictive lung function using the GLI reference values

BACKGROUND

Restrictive lung function may indicate various underlying diseases. The aim of this study was to evaluate the accuracy of different restrictive spirometry patterns (RSPs) to identify restrictive lung function (total lung capacity [TLC] < lower limit of normal [LLN]) according to reference values by the Global Lung Function Initiative (GLI) in a wide age-ranged, general population sample.

METHODS

A general population sample (n = 607, age 23-72 years, smokers 18.8%) with proper dynamic spirometry and TLC measurements, was included. Accuracy of two main categories of RSP to identify TLC < LLN were evaluated: traditional RSPs (definition 1: FVC < 80% of predicted and FEV₁ /FVC ≥ 0.7 and definition 2: FVC < LLN and FEV₁ /FVC ≥ LLN) and RSPs defined by Youden's method (definition 3: FVC < 85.5% of predicted and FEV₁ /FVC ≥ LLN and definition 4: FVC Z-score < -1.0 and FEV₁ /FVC ≥ LLN).

RESULTS

The prevalence of restrictive lung function (TLC < LLN) was 5.3%. The most accurate cut-offs for FVC to identify TLC < LLN were 85.5% for FVC% of predicted, and -1.0 for FVC Z-score. The traditional RSP definitions 1 and 2 had higher specificity (95.0% and 96.9%) but substantially lower sensitivity compared to RSP definitions 3 and 4.

CONCLUSION

Based on the GLI reference values, the RSP definition FVC < LLN and FEV₁ /FVC ≥ LLN yielded the highest specificity and may appropriately be used to rule out restrictive lung function. The RSP definition with the most favourable trade-off between sensitivity and specificity, FVC < 85.5% of predicted and FEV₁ /FVC ≥ LLN, may serve as an alternative with higher sensitivity for screening.