Preserved ratio but impaired spirometry (PRISm): Are these subjects different?

PRISm is defined as preserved ratio(FEV1/FVC>0.7) but impaired spirometry (FEV1 and/or FVC<80% of reference). Individuals with PRISm may be at risk of developing airflow obstruction, and have been reported to have worse health outcomes. To determine the prevalence and characteristics of subjects with PRISm in a health screening population. Consecutive subjects ≥18 years with no diagnosed respiratory illness undergoing spirometry as a part of health screening were enrolled. Participants were requested to complete the CAPTURE questionnaire (screening for COPD) and mMRC questionnaire. Those with PRISm were compared with those who had a normal spirometry. From November 2022-Feb 2023, 1453 individuals were screened. Mean age was 52 years (SD=12) with 60% males.51(3.51%)were diagnosed to have COPD by spirometry, and 119 (8.19%)subjects had PRISm (35 by FVC criterion, 19 by FEV1 criterion, 65 by both). In the univariate analysis those with PRISm were statistically significantly (p<0.05)older, male, had a higher BMI, and were more likely to be diabetic, hypertensive, or have heart disease. They were significantly more breathless on the mMRC scale and had higher CAPTURE scores. In the multivariable analysis, male gender, age and BMI were statistically significantly predictive variables. Subjects with PRISm appear to have poorer health status and should be followed over time. The prevalence appears to increase in men, with age and those with higher BMI.