Understanding the burden of COPD mortality: An investigation using UK electronic healthcare record data

Abstract

Chronic obstructive pulmonary disease (COPD) is a progressive disease largely attributed to longstanding exposure to tobacco smoking. Globally, since 2006, modelled COPD mortality rates have shown a downward trend with levels predicted to decrease by 21% into 2040, yet, few extensive patient level studies have been conducted to distinguish between those who die with COPD from those who die from COPD in the United Kingdom. The aim of this thesis was to describe the epidemiology of mortality in patients with COPD. The objectives included: i) to investigate COPD mortality over time in the UK population calculating all-cause and cause-specific mortality rates ii) to understand the association between environmental exposures and COPD mortality iii) to estimate the proportion of people with a diagnosis of COPD prior to a COPD-recorded death, and understand factors associated with missing lifetime diagnosis iv) to ascertain the excess risk of death among patients with COPD while taking into account competing risks. This research revealed that COPD mortality rates in the UK over the last decade have been relatively stable, contrasting large declines seen in cardiovascular disease (CVD) mortality. Trend analysis described how patients with COPD were more likely to die from neoplasms or respiratory illness, but less likely to die of CVD, than they were 10 years ago. COPD mortality rates were associated with changes in temperature but not for PM2.5,one of the most common air pollutants. Improvements in recording physician-diagnosed COPD were observed over time where as many as 96% of patients with a COPD-recorded death received a diagnosis in their lifetime, however, diagnosis is associated with significant excess risk of respiratory-related mortality compared to the general population. Collectively, these results highlight the need to evaluate interventions that specifically reduce the mortality burden at both the population level and for patients with COPD.