EFFECT OF OBESITY ON OUTCOMES IN PATIENTS WITH COPD EXACERBATION REQUIRING BI-LEVEL NONINVASIVE VENTILATION

Abstract

SESSION TITLE: Identifying Successes and Failures of NIV and Airway Clearance: From COPD to Neuromuscular Disease SESSION TYPE: Original Investigations PRESENTED ON: 10/21/2019 1:30 PM - 2:30 PM PURPOSE: Bi-level Non-Invasive Ventilation (NIV) is an important clinical tool used to improve acute hypercapnic respiratory acidosis, prevent endotracheal intubation, and decrease mortality in exacerbations of chronic obstructive pulmonary disease (COPD). However, studies show that one-third of patients who receive a trial of NIV fail, and the ability of physicians to determine success or failure rates is poor. Comorbid obesity and COPD is prevalent and associated with a higher risk of severe COPD exacerbation. In our study, we assessed the effect of body mass index (BMI) on the success of bi-level NIV in COPD exacerbation. METHODS: We performed a single-center, longitudinal retrospective cohort study of all patients admitted to a community hospital with the primary diagnosis of COPD exacerbation during a one-year period from June 2017 to June 2018. We excluded patients who did not require bi-level NIV during their stay or had a Do Not Resuscitate order at admission. 100 patients were included and divided into two groups; obese (BMI >/=30) and non-obese (BMI <30). Our primary outcome was bi-level NIV failure, defined as the need for intubation after bi-level NIV use. A Student t-test or Mann-Whitney U test was used for analysis of continuous variables. A χ² test or Fisher's exact test was used for analysis of categorical variables. RESULTS: Of 100 included admissions; we created an obese group (n=42, mean age 63.0 ± 8.8 years consisting of 29% males, 35.7% active smokers with average BMI 38.7); and a non-obese group (n=58, mean age 67.2 ± 11.4 years, consisting of 43% males, 58.6% active smokers with average BMI 22.3). Bi-level NIV failure was observed in 8 patients (19%) in the obese group and 1 (1.7%) in the non-obese group, a statistically significant difference (RR 2.37, 95% CI 1.67-3.38, p<0.01, Fisher’s exact test). When comparing obese vs non obese patients, Intensive Care Unit (ICU) admission was recorded in 28.6% vs 8.6% (p=0.014, Fisher’s exact test), with average ICU length of stay (LOS) 12.4 days vs 3.4 days and average hospital LOS 12.1 days vs 6.7 days (median 6.1 and 5.2, U=1047.5, p=0.235). Readmission rate at 30 days was 17.5% for obese patients vs 21.1% for non-obese patients, a difference that was not statistically significant. CONCLUSIONS: In patients with COPD exacerbation requiring bi-level NIV, obesity is associated with a higher risk of bi-level NIV failure and need for ICU admission. CLINICAL IMPLICATIONS: Identifying patients at higher risk of bi-level NIV failure will improve outcomes by enabling closer monitoring and early escalation of care. Mechanical effects of obesity on respiratory physiology such as decreased pulmonary compliance and a decrease in functional residual capacity below the closing capacity of small airways can result in atelectasis; a possible explanation for the high rates of bi-level NIV failure that we found in our study. DISCLOSURES: No relevant relationships by maen assali, source=Web Response no disclosure on file for David Benson; No relevant relationships by Ruth McGovern, source=Web Response No relevant relationships by Patricia Russo-Magno, source=Web Response No relevant relationships by Fatima Zeba, source=Web Response