All-Cause, Cardiovascular and Respiratory Mortality in People with Type 2 Diabetes and Chronic Obstructive Pulmonary Disease (COPD) in England: A Cohort Study Using the Clinical Practice Research Datalink (CPRD)

Background: Type 2 diabetes (T2D) and chronic obstructive pulmonary disease (COPD) are common non-communicable diseases. Both have an inflammatory nature and similar risk factors, and there is overlap and interaction between them. To date, there is a lack of research on outcomes in people that have both conditions. The aim of this study was to investigate whether the presence of COPD in people with T2D was associated with an increased risk of all-cause, respiratory-cause and cardiovascular-cause mortality.

Methods: A three-year cohort study (2017-19) was done using the Clinical Practice Research Datalink Aurum database. The study population was 121,563 people with T2D aged ≥40. The exposure was COPD status at baseline. Incident rates for all-cause, respiratory-cause and cardiovascular-cause mortality were calculated. Poisson models for each outcome were fitted to estimate rate ratios for COPD status adjusted for age, sex, Index of Multiple Deprivation, smoking status, body mass index, prior asthma and cardiovascular disease.

Results: COPD was present in 12.1% people with T2D. People with COPD had a higher all-cause mortality rate (448.7 persons per 1000 person years) compared with people without COPD (296.6 persons per 1000 person years). People with COPD also had substantially higher respiratory mortality incidence rates and moderately raised cardiovascular mortality rates. Fully adjusted Poisson models showed that people with COPD had a 1.23 (95% CI 1.21, 1.24) times higher rate of all-cause mortality as compared with those without COPD and a 3.03 (95% CI 2.89, 3.18) times higher rate of respiratory-cause mortality. There was no evidence of an association with cardiovascular mortality after adjusting for existing cardiovascular disease.

Conclusion: Co-morbid COPD in people with T2D was associated with increased mortality overall and particularly from respiratory causes. People with both COPD and T2D are a high-risk group who would benefit from particularly intensive management of both conditions.