Chronic Obstructive Pulmonary Disease and Subsequent Overall and Lung Cancer Mortality in Low-Income Adults

Melinda C Aldrich,Eric L Grogan,Timothy S Blackwell,Heather M Munro,Pierre P Massion,Michael Mumma,William J Blot,Javier J Zulueta

doi:10.1371/journal.pone.0121805

Abstract

BackgroundChronic obstructive pulmonary disease (COPD) is a known risk factor for lung cancer and a leading cause of mortality in the U.S., but its impact may not be fully appreciated, especially among low-income populations in the southeast where COPD prevalence and lung cancer incidence are elevated.MethodsWe conducted a prospective study among 26,927 low-income adults age 40–79 in the Southern Community Cohort Study who had a Center for Medicare and Medicaid Services (CMS) encounter prior to enrollment and were followed for a median of over 6 years. Using a validated algorithm for assessing COPD from CMS claims data, we estimated COPD prevalence and potential misreporting. From Cox proportional hazard models, we computed overall and lung cancer-specific mortality according to COPD status.ResultsThe overall prevalence of CMS-diagnosed COPD was 16%, but was twice as high among whites as blacks. Only 35% of these individuals, however, self-reported having COPD, with underreporting significantly greater for blacks than whites. Smoking-adjusted all-cause mortality was increased by 1.7-fold and lung cancer mortality by 2.3-fold among those with a CMS COPD diagnosis, with similar patterns in blacks and whites, but no excess was found among those self-reporting COPD and without CMS confirmation.ConclusionThe prevalence of COPD in this low-income population may be greater than previously recognized and misreporting is common. COPD is associated with elevated lung cancer mortality, even among those not self-reporting the condition.

Highlights

Chronic obstructive pulmonary disease (COPD) is a well-known risk factor for lung cancer [1,2,3,4,5,6,7,8] and investigators have voiced the need for integrated research between COPD and lung cancer to understand their common epidemiology which in turn may suggest improved strategies for reducing the burden from both conditions [9]
Smoking-adjusted all-cause mortality was increased by 1.7-fold and lung cancer mortality by 2.3-fold among those with a Centers for Medicare and Medicaid Services (CMS) COPD diagnosis, with similar patterns in blacks and whites, but no excess was found among those self-reporting COPD and without CMS confirmation
We report the prevalence of Centers for Medicare and Medicaid Services (CMS) confirmed, as well as self-reported physician-diagnosed COPD, in a large prospective cohort of blacks and whites enrolled across 12 southern states and followed for determination of overall and lung cancer mortality

Summary

Introduction

Chronic obstructive pulmonary disease (COPD) is a well-known risk factor for lung cancer [1,2,3,4,5,6,7,8] and investigators have voiced the need for integrated research between COPD and lung cancer to understand their common epidemiology which in turn may suggest improved strategies for reducing the burden from both conditions [9]. New data from the Behavioral Risk Factor Surveillance System (BRFSS) provide a 9.6% nationwide prevalence of self-reported COPD among adults over age 40 and demonstrate that COPD varies geographically across the United States, with the highest prevalence of COPD in Southern states [10]. While these data demonstrate the substantial burden of COPD, the population sampled by the BRFSS is generally of higher income than the low-income populations most afflicted by the disease [11]. Chronic obstructive pulmonary disease (COPD) is a known risk factor for lung cancer and a leading cause of mortality in the U.S, but its impact may not be fully appreciated, especially among low-income populations in the southeast where COPD prevalence and lung cancer incidence are elevated.

Methods

Results

Conclusion