Risk factors for impaired pulmonary diffusion function in convalescent COVID-19 patients: A systematic review and meta-analysis

Lung Diffusion Capacity in Patients With Bilateral COVID-19 Pneumonia: A Three-Month Follow-Up Study

OBJECTIVES

The aim of this study was to determine the short-term consequences of coronavirus disease 2019 (COVID-19) infection on pulmonary diffusion in patients with severe (but not critical) and moderately severe COVID-19 pneumonia during three months after COVID-19 infection.

METHODS

A prospective study included 81 patients with an RT-PCR-test confirmed diagnosis of COVID-19 infection treated in the COVID Department of Lung Diseases of University Clinical Hospital Mostar. Inclusion criteria were ≥18-year-old patients, COVID-19 infection confirmed using real-time RT-PCR, radiologically confirmed bilateral COVID-19 pneumonia, and diffusion capacity of the lungs for carbon monoxide (DLCO) one and three months after COVID-19 infection. The pulmonary function was tested using the MasterScreen Body Jaeger (Jaeger Corporation, Omaha, USA) and MasterScreen PFT Jaeger (Jaeger Corporation, Omaha, USA) according to American Thoracic Society guidelines one and three months after COVID-19 infection.

RESULTS

Forced vital capacity significantly increased three months after COVID-19 infection compared to the first-month control (p<0.0005). Also, a statistically significant increase in the FEV1 value (p<0.0005), FEV1%FVC ratio (p<0.005), DLCO/SB (p<0.0005), DLCO/VA value (p<0.0005), and total lung capacity (TLC) (p<0.0005) was observed in all patients.

CONCLUSION

Our study showed that recovery of DLCO/VA and spirometry parameters was complete after three months, while DLCO/SB was below normal values even after three months. Therefore, one month after the COVID-19 infection patients had partial recovery of lung function, while a significant recovery of lung function was observed three months after the COVID-19 infection.

Pulmonary function 3-6 months after acute COVID-19: A systematic review and multicentre cohort study

Aims

To describe pulmonary function 3-6 months following acute COVID-19, to evaluate potential predictors of decreased pulmonary function and to review literature for the effect of COVID-19 on pulmonary function.

Materials and methods

A systematic review and cohort study were conducted. Within the P4O2 COVID-19 cohort, 95 patients aged 40-65 years were recruited from outpatient post-COVID-19 clinics in five Dutch hospitals between May 2021-September 2022. At 3-6 months post COVID-19, medical records data and biological samples were collected and questionnaires were administered. In addition, pulmonary function tests (PFTs), including spirometry and transfer factor, were performed. To identify factors associated with PFTs, linear regression analyses were conducted, adjusted for covariates.

Results

In PFTs (n = 90), mean ± SD % of predicted was 89.7 ± 18.2 for forced vital capacity (FVC) and 79.8 ± 20.0 for transfer factor for carbon monoxide (DLCO). FVC was

Conclusion

A low DLCO 3-6 months following acute COVID-19 was observed more often than a low FVC, both in the P4O2 COVID-19 study and the literature review.

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Key Words

• Long COVID
• Post COVID-19
• Pulmonary function
• Transfer factor for carbon monoxide

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Affiliation(s)

Merel E.B. Cornelissen Department of Pulmonary Medicine, Amsterdam UMC, University of Amsterdam, 1105, AZ Amsterdam, the Netherlands Amsterdam Institute for Infection and Immunity, Amsterdam, the Netherlands Amsterdam Public Health, Amsterdam, the Netherlands
Asabi Leliveld Department of Pulmonary Medicine, Amsterdam UMC, University of Amsterdam, 1105, AZ Amsterdam, the Netherlands Amsterdam Institute for Infection and Immunity, Amsterdam, the Netherlands Amsterdam Public Health, Amsterdam, the Netherlands
Nadia Baalbaki Department of Pulmonary Medicine, Amsterdam UMC, University of Amsterdam, 1105, AZ Amsterdam, the Netherlands Amsterdam Institute for Infection and Immunity, Amsterdam, the Netherlands Amsterdam Public Health, Amsterdam, the Netherlands
Debbie Gach Department of Respiratory Medicine, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, the Netherlands School of Nutrition and Translational Research in Metabolism, Faculty of Health, Medicine and Life Sciences, Maastricht University, the Netherlands
Ivo van der Lee Department of Pulmonology, Spaarne Hospital, the Netherlands
Esther J. Nossent Department of Pulmonary Medicine, Amsterdam UMC, University of Amsterdam, 1105, AZ Amsterdam, the Netherlands
Lizan D. Bloemsma Department of Pulmonary Medicine, Amsterdam UMC, University of Amsterdam, 1105, AZ Amsterdam, the Netherlands Amsterdam Institute for Infection and Immunity, Amsterdam, the Netherlands Amsterdam Public Health, Amsterdam, the Netherlands
Anke H. Maitland-van der Zee Department of Pulmonary Medicine, Amsterdam UMC, University of Amsterdam, 1105, AZ Amsterdam, the Netherlands Amsterdam Institute for Infection and Immunity, Amsterdam, the Netherlands Amsterdam Public Health, Amsterdam, the Netherlands

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Correlation between Cardiovascular Autonomic and Pulmonary Ventilation Functions in Myasthenia Gravis Patients

This study aimed to investigate the relationship between pulmonary function and cardiac autonomic function parameters in clinically stable myasthenia gravis (MG) patients. A total of 22 MG patients and 22 healthy controls (HCs) were evaluated. Pulmonary function test parameters, heart rate variability (HRV), baroreflex sensitivity (BRS), and cardiovascular autonomic function test parameters (the Valsalva ratio, expiration/inspiration (E/I) ratio) were assessed. Compared with the HCs, the patients demonstrated a similar diffusion capacity for carbon monoxide (DLCO); a lower forced vital capacity (FVC%pred); a lower forced expiratory volume in 1 s (FEV1%pred); lower BRS and HRV, including high-frequency and total power spectral density; and a higher percentage of abnormal cardiovagal function test results (p < 0.05). A lower BRS in the patient group was associated with worse clinical disease outcomes and reduced pulmonary function (DLCO%pred, R = 0.59; TLC%pred, R = 0.48). Age, forced vital capacity, and total lung capacity predicted the E/I ratio (R2 values ranging from 0.48 to 0.49). Our study demonstrated a significant relationship between a reduced pulmonary ventilation function and respiratory mechanics with cardiovascular autonomic parameters, including the E/I ratio, BRS, and HRV measures at rest, as shown in the MG group. Future studies should focus on the interplay between respiratory and autonomic function testing, as well as pulmonary rehabilitation, to mitigate cardiovascular risk in these patients.

Long COVID: An inevitable sequela of SARS-CoV-2 infection

At present, there are more than 560 million confirmed cases of the coronavirus disease 2019 (COVID-19) worldwide. Although more than 98% of patients with severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection can survive acute COVID, a significant portion of survivors can develop residual health problems, which is termed as long COVID. Although severe COVID-19 is generally associated with a high risk of long COVID, patients with asymptomatic or mild disease can also show long COVID. The definition of long COVID is inconsistent and its clinical manifestations are protean. In addition to general symptoms, such as fatigue, long COVID can affect many organ systems, including the respiratory, neurological, psychosocial, cardiovascular, gastrointestinal, and metabolic systems. Moreover, patients with long COVID may experience exercise intolerance and impaired daily function and quality of life. Long COVID may be caused by SARS-CoV-2 direct injury or its associated immune/inflammatory response. Assessment of patients with long COVID requires comprehensive evaluation, including history taking, physical examination, laboratory tests, radiography, and functional tests. However, there is no known effective treatment for long COVID. Based on the limited evidence, vaccines may help to prevent the development of long COVID. As long COVID is a new clinical entity that is constantly evolving, there are still many unknowns, and further investigation is warranted to enhance our understanding of this disease.

Clinical predictors of lung function in patients recovering from mild COVID-19

Background

Few studies have assessed lung function in Hispanic subjects recovering from mild COVID-19. Therefore, we examined the prevalence of impaired pulmonary diffusing capacity for carbon monoxide (DLCO) as defined by values below the lower limit of normal (< LLN, < 5th percentile) or less than 80% of predicted in Hispanics recovering from mild COVID-19. We also examined the prevalence of a restrictive spirometric pattern as defined by the ratio of forced expiratory volume in 1 s (FEV₁) to forced vital capacity (FVC) being ≥ LLN with the FVC being < LLN. Finally, we evaluated previous studies to find factors correlated to impaired DLCO post-COVID-19.

Methods

In this observational study, adult patients (n = 146) with mild COVID-19 were recruited from a long-term follow-up COVID-19 clinic in Yucatan, Mexico, between March and August 2021. Spirometry, DLCO, and self-reported signs/symptoms were recorded 34 ± 4 days after diagnosis.

Results

At post-evaluation, 20% and 30% of patients recovering from COVID-19 were classified as having a restrictive spirometric pattern and impaired DLCO, respectively; 13% had both. The most prevalent reported symptoms were fatigue (73%), a persistent cough (43%), shortness of breath (42%) and a blocked/runny nose (36%). Increased age and a restrictive spirometric pattern increased the probability of having an impaired DLCO while having a blocked nose and excessive sweating decreased the likelihood. The proportion of patients with previous mild COVID-19 and impaired DLCO increased by 13% when the definition of impaired DLCO was < 80% predicted instead of below the LLN. When comparing previous studies, having severe COVID-19 increased the proportion of those with impaired DLCO by 21% compared to those with mild COVID-19.

Conclusions

One-third of patients with mild COVID-19 have impaired DLCO thirty-four days post-diagnosis. The criteria that define impaired DLCO and the severity of COVID-19 disease affects the proportion of those with impaired DLCO at follow-up. One-fifth of patients have a restrictive spirometric pattern.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02086-9.

Assessment of Long-Term Effects on Pulmonary Functions Between Severe and Non-Severe Convalescent COVID-19 Patients: A Single-Center Study in China

Objective

To explore the long-term effects of SARS-Cov-2 infection on the pulmonary function in the severe convalescent COVID-19 patients for 6 to 9 months follow-up in Beijing, China.

Methods

A total of 64 cases of COVID-19 patients were recruited for the study and discharged from the Beijing Ditan Hospital, Capital Medical University, for 6 to 9 months. COVID-19 patients were divided into non-severe (mild and moderate) and severe groups. The follow-up investigated the lung function tests, the novel coronavirus antibody (IgM and IgG), chest CT and blood tests.

Results

About 25.00% (16/64) patients had pulmonary ventilation dysfunction and 35.9% (23/64) had diffusion dysfunction. In the severe group, 56.50% (13/23) individuals showed decreased diffusion function. The diffusion dysfunction of the severe group was significantly decreased than the non-severe group (P = 0.01). Among 56 cases, the positive rate of IgG titers was 73.2% (41/56). The result of chest CT showed 55.36% (31/56) cases in nodules, 44.64% (25/56) in strip-like changes, 37.5% (21/56) in-ground glass shadow, and 5.36% (3/56) in grid shadow, which was significantly different between the severe group and the non-severe group. Patients tended to have ground glass changes in the severe group while nodules in the non-severe group.

Conclusion

For the 6 to 9 months in convalescent COVID-19 patients, 56.50% (13/23) of severe patients had pulmonary diffusion dysfunction. Convalescent COVID-19 patients should have their pulmonary function regularly tested, especially those with severe illness.