Chronic obstructive pulmonary disease is very common disease commonly seen in smokers that causes difficulty breathing and is becoming more common. It causes a huge burden to patients with respect to day-to-day symptoms and is associated with an increased risk of death compared to the general population. Previous studies have suggested that the increased risk of death is due to heart and lung disease. It is estimated that 1/3 of patients with chronic obstructive pulmonary disease die of lung disease, 1/3 of heart disease and 1/3 of lung cancer. However, given that chronic obstructive pulmonary disease is an umbrella term that is thought to cover a spectrum of diseases (e.g. chronic bronchitis - lots of infections and emphysema - mostly breathlessness) it is likely that amongst this patient population there are subgroups of people who are at increased risk of death of one specific cause over another. For example, patients who have lots of infections may be more likely to die of their chronic obstructive pulmonary disease then patients who are predominantly breathless. We will study subgroups of people with chronic obstructive pulmonary disease using routine healthcare data, to investigate causes of death to see if there are things that can potentially be modified in the future to help reduce the increased risk of death.
People with chronic obstructive pulmonary disease (COPD) are at increased risk of death compared to the general population. It is estimated that 1/3 of COPD patients with die of respiratory disease. We have undertaken work using CPRD data more recently and found that a large proportion die of COPD and that this has not really improved over time. One of the problems with COPD studies is that patients are usually investigated as a large group and yet we know that it is an umbrella term covering a spectrum of diseases. It is likely that certain phenotypes of COPD patients have different risk profiles for mortality. This study will investigate different causes of death amongst different phenotypes of COPD patients to see if there are potentially modifiable factors that could be addressed to ultimately reduce the mortality risk seen in this patient group and to help us better understand certain risk profiles that may predispose to certain causes of death.
The phenotypes we will consider are frequent and infrequent exacerbators, those who are immediately post exacerbation compared to stable, those who have chronic bronchitis compared to emphysema as well as by severity of airflow obstruction and by GOLD stage A-D. We will use CPRD Aurum linked to ONS data and HES APC data and IMD data will be used as a covariate in the analysis. The study period will be 2010-2020. Initially, in the overall cohort and then in each of the subgroups we will describe the cause of death and determine the commonest causes of death within each cohort using information derived by ONS.
We will then determine all-cause and cause-specific mortality within each phenotype. We will consider using Cox regression to determine what factors are associated with a certain cause of death.
Cause specific mortality
Jennifer Quint - Chief Investigator - Imperial College London
Hannah Whittaker - Corresponding Applicant - Imperial College London
Kieran Rothnie - Collaborator - GlaxoSmithKline Services Unlimited (UK)
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation