Mortality Related to Chronic Obstructive Pulmonary Disease and Co-morbidities in the United States, A Multiple Causes of Death Analysis.

Chronic obstructive pulmonary disease (COPD) mortality based on the underlying cause of death (UCOD) underestimates disease burden. We aimed to determine the current COPD mortality rate, trends and the distribution of co-morbidities using United States (US) multiple-cause of death (MCOD) records. All 38,905,575 death certificates of decedents aged ≥45 years in the United States were analyzed for 1999-2015. COPD was defined by ICD-10 codes J40-J44 and J47 based either on the UCOD or up to 20 contributing causes coded. Annual age-standardized COPD death rates were computed by age, gender and race/ethnicity for those with any mention of COPD. In 2015, COPD was mentioned in 11.59% (292,572 deaths) in MCOD, compared to 11.13% (243,617 deaths) in 1999, a 4% increase. However, it was reported as the UCOD for only 5.56% and 4.97% in 2015 and 1999 respectively, an 11% increase. The most common UCOD in subjects with any mention of COPD was respiratory disorders in 49% of males and 55% of females. The relative change in death rates differed between MCOD and UCOD. For example, among non-Hispanic white females aged 65-74 years the UCOD rate per 100,000 (95% CI) decreased from 163 (160-166) to 147 (145-150), average annual percent decrease (AAPD) -0.26, while the MCOD rate decreased from 308 (304-311) to 263 (260-267), AAPD -0.87. Statistics based on UCOD understated the burden of COPD in the United States. MCOD rates were twice as high as UCOD rates. The relative change in death percent or rates differed between MCOD and UCOD. MCOD analysis should be repeated periodically to help evaluate the burden of COPD-related mortality.