Among adult individuals with type 2 diabetes mellitus and at risk for heart failure with impaired relaxation of the heart mildly reduced kidney filtration function (Type 4 cardiorenal syndrome) this trial will evaluate the quantitative impact of 38 weeks of treatment with exenatide extended-release injections versus placebo. on a cardiac biomarker blood test score, cardiac fibrosis seen on magnetic resonance scanning, cardiac strain identified by ultrasonography and strain rate imaging, and a kidney urine biomarker score.