COPD Not An Independent Risk Factor for Metabolic Disorders, Study Says

There didn’t seem to be a difference in the distribution of metabolic parameters in patients with chronic obstructive pulmonary disease (COPD) compared to those without, according to a paper published in PLOS One.

Investigators from France and Canada included 263 patients with and without COPD and non-COPD in their analysis in order to compare the fat and metabolic profiles, as well as evaluate if the presence of COPD altered the metabolic risk profile. The investigators randomly selected their patients from the general population, using data from the Canadian Cohort Obstructive Lung Disease Study (CanCOLD), a longitudinal COPD study using a random population sampling. The patients were categorized as with COPD (144) or non-COPD (119), the study authors said. The median age of the patients was 65 years and two-thirds of the group were male.

The patients were selected from 9 Canadian cities between February 2012 and December 2015. The investigators gathered data about the participants’ age, gender, smoking history, medical history, current medications, body weight, height, and pulmonary function. The investigators also assessed abdominal fat on the patients and collected blood samples after a 12-hour fast.

There were no significant differences between the 2 groups in terms of triglyceride levels, total/HDL cholesterol ratio, and insulin resistance, according to the study authors. These 3 factors were positively associated with the 3 indices of adiposity, in individuals with COPD and the control patients, the study authors said. Upon further analysis, COPD status was not significantly associated with either of these 3 factors, they added.

However, a higher body mass index was associated with an increase in triglycerides, total/HDL cholesterol, and insulin resistance and current smokers with a third of additional visceral adipose tissue (VAT), the researchers learned.

The investigators also determined that a triglyceride level above 1.5 mmol/L, a total/HDL cholesterol ratio above 4 or an insulin resistance above 3 were observed in 37%, 25%, and 40% of COPD patients, respectively. Those factors were observed in 31%, 27%, and 45% of the control subjects, respectively, the study authors found.

The investigators said they conducted a “thorough statistical approach” and determined that COPD is not an independent risk factor for metabolic disorders. VAT observed in an admittedly small cohort was not considered representative of the entire population, they added.

The size of their study was a limitation, the authors noted, and their findings may not be able to be generalized to those with severe COPD or exhibiting characteristics such as inflammatory, underweight or obese, or with vascular comorbidities.

Finally, despite a reported prevalence of sleep apnea among COPD patients in the existing literature, the study authors said it was “underdiagnosed by far in this cohort.”

“COPD did not emerge as a specific risk factor for metabolic disorders or visceral adiposity,” the study authors concluded. “Although a strong mechanistic rationale can be developed for the existence of physiopathological links between chronic respiratory diseases and dyslipidemia, insulin resistance or visceral adiposity, their existence is likely restricted to specific phenotypes or to the most severely affected patients who are not widely represented in the general population.”

Reference

Viglino D, Martin M, Piché ME. Metabolic profiles among COPD and controls in the CanCOLD population-based cohort [published online April 10, 2020]. PLOS ONE. doi: 10.1371/journal.pone.0231072.