Mortality association between obesity and pneumonia using a dual restricted cohort model

Hao Wang; Chien-Chang Lee; Eric H Chou; Wan-Ting Hsu; Richard D Robinson; Ke-Ying Su; Jessica J Kirby; Dahlia Hassani

doi:10.1016/j.orcp.2019.09.007

Mortality association between obesity and pneumonia using a dual restricted cohort model

Obes Res Clin Pract. 2020 Jul-Aug;14(4):350-359. doi: 10.1016/j.orcp.2019.09.007. Epub 2020 Jul 16.

Authors

Hao Wang¹, Chien-Chang Lee², Eric H Chou¹, Wan-Ting Hsu³, Richard D Robinson¹, Ke-Ying Su⁴, Jessica J Kirby¹, Dahlia Hassani¹

Affiliations

¹ Department of Emergency Medicine, Integrative Emergency Services, John Peter Smith Health Network, 1500 S. Main St., Fort Worth, TX 76104, USA.
² Department of Emergency Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Number 7, Chung-Shan South Road, Taipei 100, Taiwan. Electronic address: cclee100@gmail.com.
³ Department of Epidemiology, Harvard T. H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.
⁴ Department of Emergency Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Number 7, Chung-Shan South Road, Taipei 100, Taiwan.

PMID: 32684413
DOI: 10.1016/j.orcp.2019.09.007

Abstract

Background: An obesity survival paradox has been reported among obese patients with pneumonia.

Aims: To determine the impact of obesity on pneumonia outcomes and analyze the correlation between in-hospital all-cause mortality and obesity among patients with pneumonia.

Methods: The United States Nationwide Readmissions Database (NRD) was retrospectively analyzed for patients with pneumonia from 2013 to 2014. We used a step-wise restricted and propensity score matching cohort model (dual model) to compare mortality rates and other outcomes among pneumonia patients based on BMI. Mortality was calculated by a Cox proportional hazard model, adjusted for potential confounders with propensity score matched analysis.

Results: A total of 70,886,775 patients were registered in NRD during the study period. Of these, 7,786,913 patients (11.0%) were considered obese and 1,652,456 patients (2.3%) were admitted to the hospital with pneumonia. Based on the step-wise restricted cohort model, the hazard ratio comparing the mortality rates among obese pneumonia patients to mortality rates among normal BMI pneumonia patients was 0.75 (95% CI 0.60-0.94). The propensity score matched analysis estimated a hazard rate of 0.84 (95% CI 0.79-0.90) and the hazard ratio estimated from the dual model was 0.82 (95% CI 0.63-1.07).

Conclusions: With the application of a dual model, there appears to be no significant difference in mortality of obese patients with pneumonia compared to normal BMI patients with pneumonia.

Keywords: Mortality; Obesity; Pneumonia.

MeSH terms

Body Mass Index
Cohort Studies
Humans
Obesity* / complications
Obesity* / mortality
Pneumonia* / complications
Pneumonia* / mortality
Proportional Hazards Models
Retrospective Studies
United States