COPD in Patients With Type 2 Diabetes Associated With Increased Overall, Respiratory Mortality

Individuals with both type 2 diabetes (T2D) and chronic obstructive pulmonary disease (COPD) had higher all-cause and respiratory-cause mortality compared with those without COPD over a 3-year period, according to a study published in the International Journal of Chronic Obstructive Pulmonary Disease.

Researchers said 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.

“T2D and COPD are common non-communicable diseases,” the authors wrote. “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.”

They used the Clinical Practice Research Datalink Aurum database to provide electronic health record information on their study population, which consisted of 121,563 people in England 40 years or older who had T2D. The study only included those who had a diagnosis code for T2D before January 1, 2018.

COPD was present in 12.1% of the study population. Those with both COPD and T2D were more likely to have preexisting asthma or cardiovascular disease and to be male, older, current smokers, and in the most deprived quintile of Index of Multiple Deprivation (IMD) compared with those who had just T2D and not COPD.

The primary outcome of the study, which was conducted from January 1, 2017, to December 31, 2019, was all-cause mortality, and the secondary outcomes were respiratory and cardiovascular mortality. When conducting the study, researchers calculated mortality rates, survival plots, and adjusted incident rate ratios by COPD status for each outcome; additional models adjusted for age, sex, IMD, smoking status, body mass index (BMI), prior asthma, and cardiovascular disease.

Those with COPD had a higher all-cause mortality rate (448.7 persons per 1000 person-years) than those without COPD (296.6 persons per 1000 person-years). At the end of the study period, those with COPD had a roughly 25% all-cause mortality survival probability and those without COPD had a 40% all-cause mortality survival probability.

Patients with COPD also had a substantially higher respiratory mortality rate as it was 3.03 (95% CI, 2.89-3.18) times higher than the rate for those without COPD. The respiratory mortality rate for those with COPD was 129.0 (95% CI, 124.4-133.7) persons per 1000 person-years, and the rate for those without COPD was 26.6 (95% CI, 25.9-27.3) persons per 1000 person-years. In terms of their respiratory mortality survival probability by the end of the study period, those with COPD had a roughly 75% survival probability, and those without COPD had close to a 100% survival probability.

Researchers found moderately raised cardiovascular mortality rates for those with COPD, but there was no evidence of an association found after adjusting for participants’ existing cardiovascular disease.

In the fully adjusted models, those with COPD had a 1.23-fold (95% CI, 1.21-1.24) higher rate of all-cause mortality and a 3.03-fold (95% CI, 2.89-3.18) higher rate of respiratory-cause mortality compared with those without COPD.

In terms of limitations, there may have been some misclassification of the exposure and cofounders because of the use of electronic health record data.

Overall, these data showed a 23% increase in all-cause mortality in patients with both T2D and COPD compared with those without COPD. Researchers also found that those with COPD had a severely increased rate of respiratory-cause mortality, but they noted that COPD did not affect cardiovascular-cause mortality when adjusted for prior cardiovascular disease.

“Further research should be implemented to examine the role of the COPD-T2D interplay in individuals, which could consequentially develop newer guidelines and update prognostic clinical indicators in people who are affected with both conditions,” the researchers concluded.

Reference

Raslan AS, Quint JK, Cook S. 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). Int J Chron Obstruct Pulmon Dis. 2023;18:1207-1218. doi:10.2147/COPD.S407085