Acute Exacerbation and Longitudinal Lung Function Change of Preserved Ratio Impaired Spirometry

Abstract

Background

Preserved ratio impaired spirometry (PRISm) is a heterogeneous disease entity. Limited data are available regarding its prevalence, clinical course, or prognosis. We aimed to evaluate the longitudinal clinical course of patients with PRISm compared with chronic obstructive pulmonary disease (COPD).

Methods

A retrospective study enrolled PRISm and COPD patients who underwent chest computed tomography and longitudinal pulmonary function tests between January 2013 and December 2020. We compared the incidence of acute exacerbations and lung function changes between PRISm and COPD patients.

Results

Of the 623 patients, 40 and 583 had PRISm and COPD, respectively. Compared to COPD patients, PRISm patients were younger, more likely to be female and have a history of tuberculosis, and less likely to be smokers. They also had less severe comorbidities, lower forced vital capacity (FVC) and diffusing capacity of the lungs for carbon monoxide (D_LCO). The clinical course was not significantly different between the PRISm and COPD patients in terms of the risk of moderate-to-severe acute exacerbations or proportion of frequent exacerbators. During follow-up, PRISm patients had a significantly slower annual decline of forced expiratory volume in 1 second, FVC, and DL_CO than COPD patients.

Conclusion

PRISm patients had no significant difference in the risk of acute exacerbations, but a significantly slower decline of lung function during longitudinal follow-up, compared with COPD patients.

Plain Language Summary

We evaluated the longitudinal clinical course of patients with preserved ratio impaired spirometry (PRISm) compared to patients with chronic obstructive pulmonary disease (COPD). PRISm and COPD patients showed no significant differences in the risk of moderate-to-severe acute exacerbations or frequent exacerbations, but the former group showed a significantly slower annual decline of lung function during longitudinal follow-up.

Keywords:

• preserved ratio impaired spirometry
• chronic obstructive pulmonary disease
• exacerbation
• lung function

Abbreviations

BMI, body mass index; COPD, chronic obstructive pulmonary disease; CT, computed tomography; D_LCO, diffusing capacity of the lungs for carbon monoxide; FEF_25–75%, forced expiratory flow between 25% and 75% of vital capacity; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; GOLD, Global Initiative for Obstructive Diseases; ILA, interstitial lung abnormality; ILD, interstitial lung disease; MPR, medication possession ratio; PRISm, preserved ratio impaired spirometry; TB, tuberculosis.

Data Sharing Statement

All data generated or analyzed during this study are included in this published article and its Supplementary Information.

Ethics Approval and Consent to Participate

This study was approved by the Institutional Review Board of Seoul Metropolitan Government–Seoul National University Boramae Medical Center (no: 30-2021-29). The requirement for informed consent from study participants was waived by the institutional review board, and this decision was based on the following reasons: 1) This study was conducted retrospectively, involving no intervention or interaction with study participants, and relied solely on existing medical records. It did not compromise the safety, welfare, and rights of the participants. 2) This study focused on the past data, it was impractical to obtain consent from all participants. 3) There was no apparent reason to anticipate refusal of consent from participants, and even if consent were waived, the study posed minimal risk to the participants. The conduct of this study and the confidentiality of patient data were maintained in accordance with the Declaration of Helsinki. The result of this study has not been published elsewhere in whole or in part and is not under consideration by another journal. The interim findings of this study were presented orally at the KATRD International Conference 2021 on November 11, 2021.

Author Contributions

All authors had access to the data, had a role in writing this manuscript, including critical review of the manuscript, and made significant contributions to this work. All authors agreed on the journal submission choice, have agreed on all revisions, gave final approval for the version to be published, and agreed to be accountable for all aspects of the work.

Disclosure

The authors report no potential conflicts of interest in this work.

Additional information

Funding

There is no funding to report.