Chronic obstructive pulmonary disease (COPD) is a life long respiratory condition which, in the UK, is usually caused by exposure to tobacco smoke. The disease course of COPD is punctuated by episodes of symptom worsening, called exacerbations. COPD exacerbations are linked with reduced quality of life, increased mortality and exert a huge cost to the NHS. Current medications to prevent exacerbations are predominantly inhaled drugs, however, they have limited effectiveness and can cause side-effects, so additional and alternative treatments are urgently needed. A few studies have found that some diabetes medications reduce the risk of COPD exacerbations. But studies assessing the effect of the most common treatment for diabetes, metformin, are sparse. Metformin improves the glucose control for people with diabetes, improving their quality of life and has been shown to improve mortality not just for diabetes, but for all causes of death. Metformin is also cheap, easily available and a safe medication. Futhermore, there is a high proportion of people with COPD, that are overweight and at risk of, or already have developed, diabetes. The aim of this real-world study is to measure the effectiveness of metformin to reduce exacerbations in COPD patients with diabetes.
The aim of this study is to determine the effectiveness of metformin to reduce COPD exacerbations. We will draw a cohort of COPD patients with diabetes between 2004 and 2021. The exposure will be metformin. The outcome will be COPD exacerbations; defined as either managed using oral corticosteroids prescribed by their GP (Aurum), a hospital admission (HES), or death (ONS). We will assess the real-world effectiveness of metformin to reduce exacerbations in patients with COPD and diabetes. We will use both a case control design (cases will have a COPD exacerbation, controls will not, exposure will be metformin) with conditional logistic regression and a self-controlled case series design (controls will be the patient themselves prior to the drug exposure, implicitly removing time-invariant confounding) with conditional Poisson regression. We will determine if any associations between metformin and exacerbations are modified by body mass index or diabetic control. We will adjust for Index of Multiple Deprivation as the marker of socioeconomic status as this may confound the association between metformin use and COPD exacerbations. The public health benefit will be to provide additional and robust evidence regarding the use of these therapeutics in COPD management.
COPD exacerbations (managed in primary care, hospital or resulted in death)
Chloe Bloom - Chief Investigator - Imperial College London
Chloe Bloom - Corresponding Applicant - Imperial College London
Bohee Lee - Collaborator - Imperial College London
Hugo Farne - Collaborator - Imperial College London
Mark Cunningham - Collaborator - Imperial College London
Pak Lim Tse - Collaborator - Imperial College London
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation