Low Peak Inspiratory Flow Rates are Common Among COPD Inpatients and are Associated with Increased Healthcare Resource Utilization: A Retrospective Cohort Study

Abstract

Background

Patients with chronic obstructive pulmonary disease (COPD) can have low peak inspiratory flow (PIF), especially after hospitalization for acute exacerbation of COPD (AECOPD).

Purpose

To characterize patients hospitalized for AECOPD, and to assess the prevalence of low PIF, changes in PIF after hospitalization, and the association of low PIF with healthcare resource utilization (HRU) outcomes.

Patients and Methods

A retrospective cohort study was conducted using electronic health record data of hospitalized COPD patients in the Wake Forest Baptist Health system (01/01/2017 through 06/30/2020). Patients with a first eligible AECOPD hospitalization (index hospitalization) who were discharged before 05/31/2020 were included. PIF was measured using the In-Check DIAL™ at both medium-low resistance (R-2) and high resistance (R-5) during the index hospitalization. For R-2 and R-5, PIF was divided into low PIF (< 60 L/min; < 30 L/min) and high PIF (≥ 60 L/min; ≥ 30 L/min) groups. The primary outcome was the prevalence of low PIF. The stability of PIF after hospitalization was described. Adjusted regression models evaluated associations between low PIF and subsequent 30-day readmissions, 90-day readmissions, and HRU outcomes, including hospitalizations, emergency department visits, inpatient days, and intensive care unit (ICU) days.

Results

In total, 743 patients with PIF measured at R-2 and R-5 during a AECOPD hospitalization were included. The prevalence of low PIF was 56.9% at R-2 and 14.7% at R-5. PIF values were relatively stable after hospitalization. Adjusted analyses showed significant increases in HRU (all-cause hospitalizations [31%], COPD hospitalizations [33%], COPD inpatient days [46%], and COPD ICU days [24%]) during the follow-up period among patients with low PIF (< 60 L/min) at R-2. The 30- and 90-day readmission risks were similar between patients with low PIF and high PIF.

Conclusion

Low PIF is common among patients hospitalized for AECOPD, relatively stable after hospital discharge, and associated with increased HRU.

Keywords:

• AECOPD
• electronic health records
• healthcare utilization
• PIF

Abbreviations

AECOPD, acute exacerbation of chronic obstructive pulmonary disease; CI, confidence interval; COPD, chronic obstructive pulmonary disease; DPI, dry powder inhaler; FEV₁, forced expiratory volume in 1 second; GOLD, Global Initiative for Chronic Obstructive Lung Disease; HR, hazard ratio; HRU, healthcare resource utilization; ICD9/10-CM, International Classification of Diseases 9th or 10th revision, clinical modification; ICU, intensive care unit; LABA, long-acting beta₂-agonist; LAMA, long-acting muscarinic antagonist; LOS, length of stay; NC, North Carolina; OR, odds ratio; PIF, peak inspiratory flow; R-2, medium-low resistance; R-5, high resistance; SDI, Social Deprivation Index; WFBH, Wake Forest Baptist Health.

Data Sharing Statement

Due to the nature of this research, participants of this study did not agree for their data to be shared publicly, so supporting data is not available.

Ethics Approval and Informed Consent

The study was conducted in accordance with the Declaration of Helsinki and approved by the WFBH Institutional Review Board (approval number IRB00058893) with a waiver of informed consent according to 45 CFR 46.116 because the research involved no more than minimal risk to the subjects and could not practicably be carried out without the waiver. Protected Health Information was stored and analyzed within secure Wake Forest Servers and only available to the study team. No data at the patient level were shared outside of the institution.

Acknowledgments

Medical writing assistance was provided by Claire Line, Ph.D., of Cactus Life Sciences (part of Cactus Communications). We would also like to acknowledge the CTSI group at WFBH who supported the authors with the data collection: Brian Ostasiewski, Wendell Futrell, and Kobby Sekyere. We would like to acknowledge the use of services provided by the Informatics Program, supported by the National Center for Advancing Translational Sciences (NCATS), National Institutes of Health, through Grant Award Number UL1TR001420.

Author Contributions

All authors had full access to the data and take responsibility for the integrity of the data and the accuracy of the data analysis. All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agreed to be accountable for all aspects of the work.

Disclosure

Brendan Clark, Jessica Franchino-Elder, Asif Shaikh, and Bonnie MK Donato are employees of Boehringer Ingelheim Pharmaceuticals, Inc. Brian J Wells reports grants from Boehringer Ingelheim, during the conduct of the study. Jill A Ohar reports a research grant and publication assistance from Boehringer Ingelheim, during the conduct of the study; personal fees from and serving on the advisory board of Mylan, Sunovion, Boehringer Ingelheim, GlaxoSmithKline, Theravance, and Verona; and grants from Sunovion for a clinical study outside of the submitted work. The authors report no other potential conflicts of interest in relation to this work. This study was presented in part at the Virtual American Thoracic Society 2021 Conference, May 14–19 (Abstract A2165; available at: https://conference.thoracic.org/program/abstract-search.php?sid=P5762).

Additional information

Funding

This study was funded by Boehringer Ingelheim. The study and the development of the manuscript was a collaboration between WFBH and Boehringer Ingelheim. The authors received no direct compensation related to the development of the manuscript. Boehringer Ingelheim was given the opportunity to review the manuscript for medical and scientific accuracy as well as intellectual property considerations. WFBH maintained ownership of the patient-level data.