ABSTRACT
Purpose: Objective documentation of airflow obstruction is often lacking inhospitalized patients treated for acute exacerbation of chronic obstructive pulmonary disease (AECOPD). The utility of spirometry performed in hospitalized patients to identify airflow obstruction, and thus a diagnosis of COPD, is unclear. Our aim was to compare inpatient spirometry, performed during an AECOPD, with outpatient spirometry. Methods: A retrospective analysis of data from patients enrolled in an AECOPD care plan was performed. As part of the plan, patients underwent inpatient spirometry to establish a COPD diagnosis and outpatient clinic spirometry within 4 weeks of hospital discharge to confirm it. Data analyzed included forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), slow vital capacity (SVC) and FEV1/ vital capacity (VC). Obstruction was defined by FEV1/VC<0.70. Results: A total of 159 patients (mean age 63.2 +/- 10.5 years) had corresponding in- and outpatient spirometry. The median days between inpatient and outpatient spirometry was 12 (interquartile range [IQR] 9-16). Inpatient spirometry had a sensitivity of 94%, specificity of 24%, positive predictive value of 83% and negative predictive value of 53% for predicting outpatient obstruction. The area under curve for using inpatient spirometry was 0.82. The mean difference between inpatient and outpatient FEV1 was 0.44 +/- 0.03 liters or 17.3 +/- 1.13 % predicted (p<0.0001) for FEV1. Conclusions: Inpatient spirometry accurately predicts outpatient airflow obstruction, thus providing an opportunity to identify patients admitted with suspected AECOPD who have no prior spirometric documentation.
ABSTRACT
RATIONALE: Dry powder inhalers (DPIs) are prescribed after hospitalization for acute exacerbation of COPD (AECOPD). Peak inspiratory flow (PIF) affects DPI delivery. OBJECTIVES: To study the impact of PIF on readmission after hospitalization for AECOPD. METHODS: A retrospective analysis of hospitalized patients, enrolled in an AECOPD care plan, was performed. Data analyzed included PIF, age, sex, length of stay, Charlson Comorbidity Index, COPD Assessment Test score, modified Medical Research Council score, percent predicted FEV1, FVC, and inspiratory capacity. A PIF equal to and less than 60 L/min was defined as suboptimal (sPIF). Outcome measures included 30- and 90-day COPD and all-cause readmissions, and days to next COPD and all-cause readmissions. RESULTS: Of the 123 subjects, 52% (n = 64) had sPIF. They had greater COPD Assessment Test scores (29.1 ± 5.9 vs. 25.3 ± 8.7; P = 0.0073), rates of 90-day COPD readmissions (28.1 vs. 13.6%; P = 0.048), fewer median days to COPD (63.5 [interquartile range (IQR), 21-89.8] vs. 144 [IQR, 66-218]; P = 0.002) and all-cause readmissions (65.5 [IQR, 24.3-107.3] vs. 101 [IQR, 54.5-205.5]; P = 0.009). PIF was the only variable (P = 0.041) that predicted days to COPD readmission in a multivariate model incorporating age, sex, percent predicted FEV1, Charlson Comorbidity Index, and inspiratory flow group. In a group of patients with sPIF (n = 22), all-cause and COPD 30- and 90-day readmission rates were significantly lower for those discharged with nebulizer compared with DPI therapy. CONCLUSIONS: sPIF is common during AECOPD and predicts all-cause and COPD readmissions. Patients with sPIF may benefit from nebulized therapies. We recommend checking PIF in patients hospitalized for AECOPD for selection of delivery devices.
