New research suggests that persons with preserved ratio impaired spirometry (PRISm) and respiratory symptoms are at risk of progressing to chronic obstructive pulmonary disease (COPD).¹

 A total of 9789 participants were enrolled for the Nagahama study; they were followed-up after 5 years. All the study subjects underwent spirometry and were given questionnaires to gather information about respiratory symptoms such as prolonged cough, sputum and dyspnea including comorbid conditions. The aim of the study was to examine PRISm in relation to respiratory symptoms through a large-scale, longitudinal general population investigation. The aim of the study was to examine PRISm in relation to respiratory symptoms through this large-scale, longitudinal general population investigation. The aim of the study was to examine PRISm in relation to respiratory symptoms through this large-scale, longitudinal investigation involving the general population.

Findings published in the Annals of the American Thoracic Society reveal that 438 of the 9760 patients who were examined overall had PRISm, which was independently correlated with dyspnea. Around 53% of them reported respiratory symptoms. 73% of the subjects with respiratory symptoms continued to have the symptoms, while 39% of the subjects with PRISm without symptoms at baseline, developed respiratory symptoms within 5 years. PRISm was also found to be a risk factor for the development of airflow limitation among the people with respiratory symptoms but without airflow limitation at baseline, even after controlling for smoking history and comorbidities.

PRISm is characterized by a FEV1 of <80% predicted and a FEV1/forced vital capacity (FVC) ratio of ≥0·70. While the condition is “transient” in most individuals, some are at risk of progressive impairment in pulmonary function.² This study shows that over half of the participants with PRISm had respiratory symptoms and dyspnea was a prominent feature of PRISm. Around three-fourth of them had persistent respiratory symptoms over the 5 years of this study. Given the finding that PRISm itself is an independent risk factor for the development of COPD among subjects with respiratory symptoms, the clinical course of individuals with symptomatic PRISm should be carefully monitored since PRISm has been described as a “precursor” of COPD.² 

References

1. Mariko Kogo, et al. Longitudinal changes and association of respiratory symptoms with preserved ratio impaired spirometry (PRISm): The Nagahama Study. Ann Am Thorac Soc. 2023 Nov;20(11):1578-1586. doi: 10.1513/AnnalsATS.202301-050OC.
2. Daniel H Higbee, et al. Prevalence, risk factors, and clinical implications of preserved ratio impaired spirometry: a UK Biobank cohort analysis. Lancet Respir Med. 2022 Feb;10(2):149-157. doi: 10.1016/S2213-2600(21)00369-6.