Increasing daily physical activity fails to improve cardiac outcomes in Severe COPD patients

A recent study found that a 15% increase in daily physical activity over 3 months did not improve cardiac outcomes in COPD. The study was published in the Journal of Chronic Obstructive Pulmonary Disease.  

Cardiovascular diseases in COPD affect nearly half of the affected population. It is a huge disease burden causing mortality and morbidity. Cardiovascular pathologies in COPD can be detected by prolongation of the heart rate corrected QT interval (QTc) generated from the ECG. Evidence shows that there is an association between reduced pulmonary function and longer QTc. Literature shows that increased physical activity (PA) influences QTc and also endothelial function in COPD, but the relation is not established. Hence researchers conducted a study to investigate if PA is a modifying factor of QTc in COPD. 

A secondary outcome analysis from a randomized controlled trial investigating the effects of a 3-month pedometer-based program to improve PA was done on 59 participants. 12-lead ECG was assessed at baseline and after 3 months. PA was measured using a validated triaxial accelerometer of a multisensory activity monitor at baseline and after 3 months. Standard pulmonary function testing was done to measure forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC). 

Findings: 

Patients were grouped into improvers (IG) having 23 participants and non-improvers (NG) having 36 participants. 

The mean age of the improvers was 63 years, and the non-improvers was 68 years. 

10 patients in IG and 21 in the NG showed prolonged QTc at baseline. 

QTc in the IG decreased by 27 ms and in the NG group by 13 ms after 3 months of intervention but the mean group difference showed no evidence of a difference between the two groups.

Multiple regression modeling, including adjustment for baseline QTc, sex, QT-prolonging medications, BMI, smoking status, and FEV1%, showed no evidence for an association between an improvement of ≥15% PA and QTc reduction. 

In patients with severe to very severe COPD, a 15% improvement in physical activity over 3 months duration could not reduce the QTc interval. 

Further reading: DOI:10.1080/15412555.2022.2101992

Kuhn M, Kohlbrenner D, Sievi NA, Clarenbach CF. Increasing Daily Physical Activity and Its Effects on QTc Time in Severe to Very Severe COPD: A Secondary Analysis of a Randomised Controlled Trial. COPD. 2022 Jul 14;19(1):339-344.