Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jul;168(1):83-94.
doi: 10.1016/j.chest.2025.02.025. Epub 2025 Mar 8.

Importance of Preserved Ratio Impaired Spirometry as a Risk Factor for Development of COPD, Also in Those Who Do Not Smoke

Helena Backman  1 , Tomi Myrberg  2 , Linnea Hedman  3 , Caroline Stridsman  3 , Eva Rönmark  3 , Anne Lindberg  3
Affiliations

Importance of Preserved Ratio Impaired Spirometry as a Risk Factor for Development of COPD, Also in Those Who Do Not Smoke

Helena Backman et al. Chest. 2025 Jul.

Abstract

Background: COPD is largely underdiagnosed. Active identification of cases is crucial to establish preventive measures before manifestation of clinical disease. The significance of different spirometric patterns preceding COPD, especially preserved ratio impaired spirometry (PRISm), has been highlighted but remains unclear.

Research question: Which clinical characteristics, smoking habits, and spirometric patterns, with primary focus on PRISm findings, precede the development of airway obstruction (AO)?

Study design and methods: The OLIN COPD Study was established from 2002 through 2004. After re-examination of population-based cohorts, individuals with AO (n = 993; FEV1 to VC ratio < 0.70) were identified together with control participants without AO (n = 993; FEV1 to VC ratio ≥ 0.70). Most of these people had participated in examinations during the 1980s or 1990s, and in total, 902 cases and 819 control participants had previous clinical data. Logistic regression was performed with case status as outcome and spirometric patterns, age, sex, smoking habits, and BMI at first examination as covariates.

Results: The mean (SD) person-years between first examination and inclusion in the OLIN COPD Study was 10.5 (4.0) years. At first examination, the prevalence of PRISm was higher in cases (18.6%) vs control participants (13.4%). Current smoking was more common in cases (45.1% vs 18.2%), whereas former smoking was similar (31.8% vs 34.9%). Cases reported more respiratory symptoms (78.0% vs 44.3%) than control participants. At first examination, PRISm, current smoking, and former smoking were strongly associated with becoming a case when adjusted for confounders, with adjusted OR (aOR) of 3.5, 4.1, and 1.5, respectively. When stratifying for smoking habits, aORs for PRISm in those with current smoking, former smoking, and nonsmoking status were 2.9, 3.8 and 3.7, respectively.

Interpretation: In this study, PRISm was associated with transition into AO corresponding to COPD within 1 decade, independent of smoking habits and with similar strength of association among those who have never smoked, who formerly smoked, and who currently smoke.

Keywords: COPD; PRISm; asthma; case-control studies; dyspnea; productive cough; respiratory symptoms; smoking; spirometry.

PubMed Disclaimer

Conflict of interest statement

Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: H. B. reports personal fees from Chiesi, outside the submitted work. C. S. reports personal fees from GlaxoSmithKline, AstraZeneca, Chiesi, and TEVA and fees for advisory board work from AstraZeneca and GlaxoSmithKline, all outside the submitted work. A. L. reports personal fees from AstraZeneca and fees for advisory board work from AstraZeneca, GlaxoSmithKline, Boehringer Ingelheim, and Novartis, all outside the submitted work. None declared (T. M., L. H., E. R.).

Figures

Figure 1
Figure 1
A, B, Illustrations showing distributions of spirometric patterns among cases (A) and control participants (B): NLF, AO, and PRISm or missing at first examination. AO = airway obstruction; NLF = normal lung function; PRISm = preserved ratio impaired spirometry.
Figure 2
Figure 2
A, B, Graphs showing ORs with 95% CIs from logistic regression models comparing cases with control participants, unadjusted (red) and adjusted (blue), for smoking habits (former or current smoking, using nonsmoking as reference [white]) and spirometric patterns (PRISm, using normal spirometry findings as reference [white]) at first examination: among all individuals (A) and stratified by smoking habits (B). Outcome: airway obstruction (ie, being a case in the OLIN COPD Study, control participants as reference). Unadjusted: adjusted for cohort only. Adjusted: with spirometric patterns, age, sex, smoking habits, BMI, and cohort at first examination included as covariates in the model. PRISm = preserved ratio impaired spirometry.
Figure 3
Figure 3
A, B, Illustrations showing distribution by spirometric pattern among cases (A) and control participants (B): NLF, AO, RSP only, PRISm only, and both RSP and PRISm or missing at first examination. AO = airway obstruction; NLF = normal lung function; PRISm = preserved ratio impaired spirometry; RSP = restrictive spirometric pattern.
Figure 4
Figure 4
A, B, Graphs showing ORs with 95% CIs from logistic regression models comparing cases with control participants, unadjusted (red) and adjusted (blue), for smoking habits (former or current smoking, using nonsmoking as reference [white]) and spirometric patterns (RSP only, PRISm only, or both RSP and PRISm, using normal spirometry findings as reference [white]) at first examination among all participants (A) and stratified by smoking habits (B). Outcome: airway obstruction (ie, being a case in the OLIN COPD Study, control participants as reference). Unadjusted: adjusted for cohort only. Adjusted: with spirometric patterns, age, sex, smoking habits, BMI, and cohort at first examination as covariates in the model. In stratified analyses, smoking habits were not included as covariates. PRISm = preserved ratio impaired spirometry; RSP = restrictive spirometric pattern.
See this image and copyright information in PMC

References

    1. Adeloye D., Song P., Zhu Y., et al. Global, regional, and national prevalence of, and risk factors for, chronic obstructive pulmonary disease (COPD) in 2019: a systematic review and modelling analysis. Lancet Respir Med. 2022;10(5):447–458. - PMC - PubMed
    1. Boers E., Barrett M., Su J.G., et al. Burden of chronic obstructive pulmonary disease through 2050. JAMA Netw Open. 2023;6(12) - PMC - PubMed
    1. Siddharthan T., Grigsby M.R., Goodman D., et al. Association between household air pollution exposure and chronic obstructive pulmonary disease outcomes in 13 low- and middle-income country settings. Am J Respir Crit Care Med. 2018;197(5):611–620. - PMC - PubMed
    1. Lamprecht B., Soriano J.B., Studnicka M., et al. Determinants of underdiagnosis of COPD in national and international surveys. Chest. 2015;148(4):971–985. - PubMed
    1. Axelsson M., Backman H., Nwaru B.I., et al. Underdiagnosis and misclassification of COPD in Sweden: a Nordic Epilung study. Respir Med. 2023;217 - PubMed