Association between Microvascular Disease and Cardiorespiratory Fitness among Adults with Type 2 Diabetes.

OBJECTIVE: Little is known about the extent to which microvascular disease is associated with cardiorespiratory fitness (CRF) among individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 4,766 participants with type 2 diabetes underwent maximal exercise testing in the Look AHEAD study at baseline. Low CRF was defined based on the Aerobics Center Longitudinal Study reference standards. Microvascular disease was defined as ≥1 of diabetes-related kidney disease (DKD), retinopathy, neuropathy. The burden of microvascular disease was defined as the number of microvascular beds affected. RESULTS: Of the 4,766 participants (mean age 58.9 years± 6.7 years, 58.5% women, 66.1% White individuals), 1,761 (37%) had microvascular disease. Participants with microvascular complications in three vascular territories had a lower CFR than those without any microvascular disease (mean adjusted metabolic equivalent of task [MET]: 6.58 vs.7.26, P=0.001). Participants with any microvascular disease had higher odds of low CRF compared to those without microvascular disease (adjusted odds ratio [aOR]:1.45, 95% CI 1.24 - 1.71). An increasing burden of microvascular disease was associated with higher odds of low CRF (aOR for microvascular disease in 3 vascular territories - 2.82, 95% CI 1.36 – 5.85). aORs for low CRF were 1.24 (95% CI 0.99 - 1.55), 1.34 (95% CI 1.02 - 1.76), and 1.44 (95% CI 1.20 - 1.73) for neuropathy, retinopathy and DKD associations, respectively. CONCLUSION: In a large cohort of adults with type 2 diabetes, the presence of microvascular disease and its burden were independently associated with lower CRF.