Preserved Ratio Impaired Spirometry in US Primary Care Patients Diagnosed with Chronic Obstructive Pulmonary Disease.

Background: Preserved ratio impaired spirometry (PRISm) represents a population with spirometry results that do not meet standardized COPD obstruction criteria, yet present with high respiratory symptom burden and might benefit from respiratory management and treatment. We aimed to determine prevalence of PRISm in US primary care patients diagnosed with COPD, describe their demographic, clinical, and CT scan characteristics. Methods: An observational registry study utilizing the US APEX COPD registry, composed of patients diagnosed with COPD aged 35+ years. Demographic and clinical data were collected from EHRs and complemented by questionnaires. Multivariable logistic regression was performed to assess whether PRISm predicts lung function decline. Results: Prevalence of PRISm within a primary care population clinically diagnosed with COPD was 23.6% (678/2866, 95% CI 22.0-25.1). Those with PRISm were more likely female (55.9% vs 46.9%), younger (66.3±11.1 vs 69.2±10.3 years), with a greater mean BMI (33.5±9.2 vs 27.8±7.2 kg/m Interpretation: One in four primary care patients with clinically diagnosed COPD in a large US registry fulfil the spirometric definition of PRISm rather than COPD, but suffers from emphysema in CT and significant respiratory symptoms.