Increased mortality in patients with severe COPD associated with high-intensity exercise: a preliminary cohort study

TY - JOUR

T1 - Increased mortality in patients with severe COPD associated with high-intensity exercise

T2 - a preliminary cohort study

AU - Schaadt, Lone

AU - Christensen, Robin

AU - Kristensen, Lars Erik

AU - Henriksen, Marius

PY - 2016/9/26

Y1 - 2016/9/26

N2 - INTRODUCTION: Intensity of exercise is believed to be a key determinant of response to chronic obstructive pulmonary disease (COPD) rehabilitation. We hypothesized that a higher intensity of exercise, in combination with physiotherapist-led instructions and education in management of breathlessness, would lead to better self-management, possibly delaying calls to the emergency service and preventing hospitalization.OBJECTIVE: We aimed to test this hypothesis in a subsequent randomized trial, and in order to test study processes and estimate hospitalization rates, we did a small preliminary prospective cohort study on severe COPD patients referred to outpatient rehabilitation.METHODS: In 2013, four rehabilitation courses were scheduled (spring, summer, autumn, and winter) each lasting 8 weeks and including eight to ten patients. This preliminary study was designed as a controlled cohort study. The bi-weekly exercise sessions in the spring and autumn courses included a high-intensity walking exercise at 95% of estimated VO2 max for as long as possible. The other two rehabilitation courses included the usual walking exercise intensity (85% of estimated VO2 max). Hospitalization rates were assessed from the participants' medical records in an 18-month period.RESULTS: We were able to enroll 31 patients in total (15 in the high-intensity exercise group and 16 in regular intensity). There were no group differences in the hospitalization rates. However, during review of the medical records, we observed a striking mortality rate among participants who had attended the high-intensity rehabilitation courses (five deaths) compared to the standard rehabilitation (zero deaths). Four of the five deaths were COPD exacerbations. Fisher's exact test was statistically significant (P=0.046), as was a log-rank test (P=0.019) of the Kaplan-Meier estimated survival rates.CONCLUSION: These results from this small preliminary cohort study are alarming and raise concerns about the possible serious risks associated with high-intensity exercise rehabilitation of severe COPD patients.

AB - INTRODUCTION: Intensity of exercise is believed to be a key determinant of response to chronic obstructive pulmonary disease (COPD) rehabilitation. We hypothesized that a higher intensity of exercise, in combination with physiotherapist-led instructions and education in management of breathlessness, would lead to better self-management, possibly delaying calls to the emergency service and preventing hospitalization.OBJECTIVE: We aimed to test this hypothesis in a subsequent randomized trial, and in order to test study processes and estimate hospitalization rates, we did a small preliminary prospective cohort study on severe COPD patients referred to outpatient rehabilitation.METHODS: In 2013, four rehabilitation courses were scheduled (spring, summer, autumn, and winter) each lasting 8 weeks and including eight to ten patients. This preliminary study was designed as a controlled cohort study. The bi-weekly exercise sessions in the spring and autumn courses included a high-intensity walking exercise at 95% of estimated VO2 max for as long as possible. The other two rehabilitation courses included the usual walking exercise intensity (85% of estimated VO2 max). Hospitalization rates were assessed from the participants' medical records in an 18-month period.RESULTS: We were able to enroll 31 patients in total (15 in the high-intensity exercise group and 16 in regular intensity). There were no group differences in the hospitalization rates. However, during review of the medical records, we observed a striking mortality rate among participants who had attended the high-intensity rehabilitation courses (five deaths) compared to the standard rehabilitation (zero deaths). Four of the five deaths were COPD exacerbations. Fisher's exact test was statistically significant (P=0.046), as was a log-rank test (P=0.019) of the Kaplan-Meier estimated survival rates.CONCLUSION: These results from this small preliminary cohort study are alarming and raise concerns about the possible serious risks associated with high-intensity exercise rehabilitation of severe COPD patients.

KW - Journal Article

U2 - 10.2147/COPD.S114911

DO - 10.2147/COPD.S114911

M3 - Journal article

C2 - 27713626

SN - 1178-2005

VL - 11

SP - 2329

EP - 2334

JO - International Journal of Chronic Obstructive Pulmonary Disease

JF - International Journal of Chronic Obstructive Pulmonary Disease

IS - 1

ER -