Prevalence and characteristics of adults with preserved ratio impaired spirometry (PRISm): Data from the BOLD Australia study

Background: Individuals with Preserved Ratio Impaired Spirometry (PRISm), defined as FEV1/FVC >= 0.7 and FEV1 <80% predicted, are at higher risk of developing COPD. However, data for Australian adults are limited. We aimed to describe prevalence of PRISm and its relationship with clinical characteristics in Australia. Method: Data from the Burden of Lung Disease (BOLD) Australia study of randomly selected adults aged >= 40 years from six sites was classified into airflow limitation, PRISm, or normal spirometry groups. Demographic, clinical characteristics, and lung function were compared between groups. Results: Of the study sample (n = 3518), 387 (11%) had PRISm, 549 (15.6%) had airflow limitation, and 2582 (73.4%) had normal spirometry. PRISm was more common in Indigenous Australian adults. Adults with PRISm had more frequent respiratory symptoms, more comorbidities, greater health burden and poorer quality of life than those with normal spirometry. Pre- and post-bronchodilator FEV1 and FVC were lower in adults with PRISm than those with airflow limitation. Adults with PRISm were less likely to use respiratory medicine than those with airflow limitation (OR = 0.56, 95% CI 0.38-0.81). Conclusions: PRISm was present in 11% of adults in this study and they had similar respiratory symptoms and health burden as adults with airflow limitation.