Chronic obstructive pulmonary disease (COPD) is a common disease of the lungs. People with COPD experience breathlessness, coughing and sputum (phlegm), as well as periods of worsening of symptoms (exacerbations) where they may need additional treatment or be hospitalised. Many people with COPD have a mental health diagnosis, such as anxiety, depression, or severe mental illness.
Some studies have shown that people with COPD who also have a mental health diagnosis may have a higher risk of COPD exacerbations and have a higher death rate compared with people with COPD and no mental health condition. However, many of these studies are small and no studies have looked at this relationship in a large dataset from the UK.
Therefore, the objectives of this study are:
1. We will describe and compare the characteristics of COPD patients with and without a mental health diagnosis.
2. In people with COPD, we will investigate the relationship between having any mental health diagnosis and the risk of COPD exacerbation and the risk of death.
3. To explore the impact of different mental health conditions (depression, anxiety, severe mental illness) on the risk of COPD exacerbation and the risk of death, we will conduct three separate analyses in groups of people with these specific mental health diagnoses.
If we find a link between mental health conditions in COPD and exacerbations or death, this will provide useful information for patients and healthcare practitioners, and perhaps support doctors to manage COPD patients with mental health conditions more effectively.
Aims and objectives: Among people with COPD, to estimate 1. the association between a diagnosis of any mental health condition and COPD exacerbations; 2. the association between a diagnosis of any mental health condition and all-cause mortality; and 3. the associations between specific mental health conditions (depression, anxiety, severe mental illness) and exacerbations and mortality.
The study population will be adults diagnosed with COPD. The exposed group will be those with a diagnosis of a mental health condition (depression, anxiety, or severe mental illness) prior to their COPD diagnosis. The unexposed group will be those with no record of a mental health condition (before or after the COPD diagnosis). Primary outcome is COPD exacerbations, defined as a prescription for antibiotic or oral corticosteroid; secondary outcome is all-cause mortality. The data source will be Primary care records extracted from CPRD GOLD.
We will conduct a retrospective, matched cohort study in patients diagnosed with COPD. To explore the association between mental health conditions and COPD exacerbations (count data), we will calculate crude incident rates and adjusted incident rate ratios using Poisson regression, adjusting for key confounders. To investigate the association with all-cause mortality, we will calculate crude hazard ratios (HRs) and adjusted hazard ratios (aHRs) using Cox proportional hazards models, adjusting for key confounders. We will assess the proportional hazards assumption using log-log plots and the Schoenfeld residuals test. All analyses will be conducted in Stata.
If an association between mental health conditions in COPD and patient outcomes is found, this will provide useful information for patients and clinicians, and potentially support improved management of patients with comorbid mental health conditions.
There are two outcomes, 1. exacerbations of COPD and 2. all-cause mortality. COPD exacerbation will be defined as a record of a prescription for antibiotics or oral corticosteroids or both in COPD patients during the follow-up period. All-cause mortality will be obtained from primary care records.
Nicola Adderley - Chief Investigator - University of Birmingham
Nicola Adderley - Corresponding Applicant - University of Birmingham
Amanda Farley - Collaborator - University of Birmingham
Yiping Wu - Collaborator - University of Birmingham
Practice Level Index of Multiple Deprivation