LAUSR

Introduction: Pulmonary function is reduced and arterial stiffening is increased in type 1 diabetes. While increased arterial stiffness is associated with greater risk of cardiovascular disease in type 1 diabetes, the association between reduced pulmonary function and health outcomes in this population is less understood. The subendocardial viability ratio (SEVR), a ratio comparing myocardial perfusion to cardiac workload, may provide useful information pulmonary function and myocardial hypoxemia in the context of pulmonary function in type 1 diabetes. Hypothesis: We tested the hypothesis that impaired pulmonary function (i.e., percent predicted forced vital capacity [FVCpp], forced expiratory volume at 1 second [FEV 1 pp], and FEV 1 /FVC), is associated with reduced SEVR in adults with and without type 1 diabetes. Methods: We conducted pulse wave analysis on 208 adults with type 1 diabetes (mean age 52±9 years) and 285 adults without diabetes (mean age 55±8 years) to obtain the outcome measure of SEVR. All participants underwent non-bronchodilated spirometry testing to obtain FVCpp, FEV 1 pp, and FEV 1 /FVC. Independent t-tests were used to test the difference by diabetes status in each pulmonary function measure and the SEVR. Linear regression models were used to test the association between each pulmonary function measure and SEVR after adjustment for age, sex, diabetes status, smoking status, and heart rate. Results: FVCpp and FEV 1 pp were both significantly lower in type 1 diabetes (87.5% and 85.6%, respectively) compared to controls without diabetes (95.6% and 94.9%, respectively; p<0.001 for both). There was no significant difference by diabetes status in FEV 1 /FVC (97.5% vs. 99.0%, p=0.07). SEVR was also significantly lower in type 1 diabetes (137.5 vs. 159.6, p<0.001). In an adjusted linear model, both FVCpp and FEV 1 pp were associated with SEVR. FVCpp was associated with 0.086 greater SEVR per SD (p=0.002), and FEV 1 pp was associated with 0.058 greater SEVR per SD (p=0.04). FEV 1 /FVC was not significantly associated with SEVR (p=0.37). In the model testing FVCpp, type 1 diabetes was associated with 0.18 lower SEVR (p<0.001). Similarly, in the model testing FEV 1 pp, type 1 diabetes was associated with 0.19 lower SEVR (p<0.001). After accounting for FEV 1 /FVC, type 1 diabetes was still associated with 0.20 lower SEVR (p<0.001). Conclusions: In conclusion, reduced pulmonary function was associated with reduced SEVR in cross-sectional analysis, but type 1 diabetes remained independently associated with reduced SEVR after accounting for reduced pulmonary function. The mechanism between pulmonary function and SEVR is unclear, but future research may reveal pathways or shared etiologies in type 1 diabetes.