Exercise seems to be less effective for coronary artery disease patients with diabetes and advanced vascular disease, according the the PhD thesis of Rune Byrkjeland.

MAIN RESULTS:

1. One year of exercise did not reduce blood sugar or improve maximal oxygen uptake in patients with type 2 diabetes and coronary artery disease. Moreover, carotid intima-media thickness and markers of endothelial function did not improve following exercise.
2. However, improvements were seen in patients with the least advanced vascular disease.
3. The half of patients with the lowest physical capacity at baseline had three times higher odds of being among those with highest insulin resistance.

THESIS DEFENCE:

Thesis: Effects of exercise training on exercise capacity, glycemic control and atherosclerosis in patients with type 2 diabetes and coronary artery disease.
Candidate: Rune Byrkjeland
Time: November 20, 2017 at 11:15
Place: Domus Academica, University of Oslo: Gamle festsal
Link to university website (in Norwegian)

SUMMARY:

137 patients with type 2 diabetes and coronary artery disease were included in Byrkjeland’s study. Half of them were randomized to three weekly exercise sessions for one year, including two group-based and one individual session. 52 patients in the exercise group completed at least 40 % of the prescribed exercise and were included in the analysis. Only 21 patients completed at least 70 % of the exercise sessions.

(1) At baseline, insulin resistance was inversely associated with exercise capacity. The odds of having an exercise capacity below median was three times higher in the patients with HOMA2-IR values above median.

(2) Exercise did not reduce HbA_1c, fasting blood glucose or HOMA2-IR significantly. Oxygen uptake tended to improve more than in the control group. In patients with less advanced disease, i.e. without previous acute myocardial infarction and microvascular complications of diabetes, exercise did improve HbA_1c and physical capacity.

(3) Exercise did not reduce carotid intima-media thickness measured with ultrasound of the distal part of the common carotid artery. However, in patients without identified carotid plaques exercise reduced plaques compared to the control group.

(4) Endothelial function did not improve following exercise. The function was assessed by seven biomarkers in the circulation. The group of patients who experienced reduced endothelial activation after one year of exercise, improved their HbA1c more than those who did not.

REFERENCES:

(1) Byrkjeland, R., Edvardsen, E., Njerve, I. U., Arnesen, H., Seljeflot, I., & Solheim, S. (2014). Insulin levels and HOMA index are associated with exercise capacity in patients with type 2 diabetes and coronary artery disease. Diabetology & metabolic syndrome, 6(1), 36.

(2) Byrkjeland, R., Njerve, I. U., Anderssen, S., Arnesen, H., Seljeflot, I., & Solheim, S. (2015). Effects of exercise training on HbA1c and VO2peak in patients with type 2 diabetes and coronary artery disease: a randomised clinical trial. Diabetes and Vascular Disease Research, 12(5), 325-333.

(3) Byrkjeland, R., Stensæth, K. H., Anderssen, S., Njerve, I. U., Arnesen, H., Seljeflot, I., & Solheim, S. (2016). Effects of exercise training on carotid intima-media thickness in patients with type 2 diabetes and coronary artery disease. Influence of carotid plaques. Cardiovascular diabetology, 15(1), 13.

(4) Byrkjeland, R., Njerve, I. U., Arnesen, H., Seljeflot, I., & Solheim, S. (2017). Reduced endothelial activation after exercise is associated with improved HbA1c in patients with type 2 diabetes and coronary artery disease. Diabetes and Vascular Disease Research, 14(2), 94-103.