Temporal trends and socio-demographic disparities in COPD–lung cancer co-occurrence mortality in the United States: a 22 year analysis (1999–2020)

Chronic Obstructive Pulmonary Disease (COPD) and lung cancer remain among the leading causes of mortality worldwide, with a high burden reported in the United States. While both conditions often coexist and share risk factors such as smoking and environmental exposure, temporal mortality trends and disparities across demographics remain underexplored. To analyze age-adjusted mortality rates (AAMRs) associated with the co-occurrence of COPD and lung cancer (COPD–LC) in the United States from 1999 to 2020, with a specific focus on temporal shifts and disparities across sex, race/ethnicity, and geographic regions. Mortality data were retrieved from the CDC WONDER database. The underlying causes of death were identified using ICD-10 codes (J40–J44 for COPD and C33–C34 for lung cancer). AAMRs were standardized to the 2000 U.S. population. Joinpoint regression analysis was used to calculate Annual Percent Changes (APCs) and identify statistically significant shifts in mortality trends. Subgroup analyses were conducted by sex, race/ethnicity, and census regions. Mortality associated with the co-occurrence of COPD and lung cancer was identified using multiple-cause-of-death coding. A total of 587,762 deaths involving co-occurring chronic obstructive pulmonary disease (COPD) and lung cancer were identified in the United States between 1999 and 2020. Overall age-adjusted mortality rates (AAMRs) declined from 8.904 per 100,000 population in 1999 to 7.128 in 2020. Joinpoint regression demonstrated a three-segment trend, including a non-significant decline from 1999 to 2006 (APC: − 0.40), a significant decline from 2006 to 2018 (APC: − 1.77%), and a non-significant increase from 2018 to 2020 (APC: 0.71%). Sex-stratified analysis showed persistently higher mortality among males, although mortality declined more substantially in males than in females over time. Non-Hispanic White individuals demonstrated the highest mortality burden, whereas Asian or Pacific Islander and Hispanic populations had the lowest AAMRs. Regionally, mortality rates remained highest in the Midwest and South, while the West exhibited the steepest decline. Non-metropolitan areas demonstrated persistently elevated mortality rates compared with metropolitan regions. While mortality among individuals with co-occurring COPD and lung cancer has declined significantly over two decades, demographic disparities based on sex, race, and geography persist. These findings highlight the need for equity-driven public health interventions and early detection strategies tailored to high-risk populations.