by Crystal Phend
Senior Staff Writer, MedPage Today

02.19.2014

Slowing down in exercise habits was associated with a subsequent increase in hospitalizations for exacerbation of chronic obstructive pulmonary disease (COPD), a prospective Spanish study showed.
The odds of hospitalization for COPD exacerbation rose 2.49-fold in the 3 years after a shift from a daily walking routine of up to roughly 2 miles per day to none, or from getting around 2 to 4 miles daily to less or none, compared with staying highly active (P=0.004), Cristobal Esteban, MD, of the Hospital de Galdakao-Usansolo, Spain, and colleagues found.

Those who moved from the highest level of activity to any lower category also doubled their subsequent risk (OR 2.13, P=0.017), the group reported online in Respirology.

The associations were independent of age, lung function, and prior hospitalizations for exacerbations.

“This suggests that small changes in physical activity habits could significantly improve an important outcome as hospitalization during exacerbation of COPD in those patients,” the researchers concluded.

However, maintaining a lower level of physical activity also roughly doubled risk compared with sticking to a higher level of physical exercise.

And moving up a category from none to some exercise didn’t wipe out the disadvantage of not being highly active (OR 1.51 versus staying in the high category, P=0.645). Nevertheless, plenty of prior studies have shown benefits to regular exercise in COPD, both in lower hospitalization risk and better survival, the researchers pointed out.

The mechanism could be decreasing systemic inflammation, improving lung efficiency, or strengthening lung muscles, but reverse causation and unmeasured confounding were possible as well, they acknowledged.

Their study included 543 consecutive stable COPD patients seen at five outpatient respiratory clinics affiliated with a single Spanish hospital who self-reported physical activity at baseline and 2-year follow-up, from which the change in activity was calculated.

The emphasis was on walking, which “is by far the most usual form of physical activity during spare time in our environment,” the researchers noted.

Low physical activity was considered less than 1.9 miles (3 km) per day or less, moderate was 1.9 to 3.7 miles (3 to 6 km) daily, and high was anything above that.