Here are the results of a study from Sackler School of Medicine in Tel-Aviv University, with 242 men participating.  From the abstract:

RESULTS: Overall, 242 men, with a mean age of 63.7 +/- 12.0 years, were included in the study. ED and depressive symptoms were found in 76% and 47.9% of men, respectively, whereas 94 (38.8%) men suffered from both. The prevalence of diabetes mellitus and the mean age were significantly higher, whereas the mean MHI5 scores were significantly lower, in the group with ED than that without.

ED was associated independently with age (P <.0001) and depressive symptoms (P = .007), but not with the number of obstructed coronary arteries, history of diabetes mellitus, hypertension, or smoking. After controlling for age and diabetes mellitus, the scores of SHIM were positively correlated with MHI5 scores (r = .14; P = .03).

CONCLUSIONS: These results validate the high prevalence of both ED and depressive symptoms in men with CAD. ED in men with CAD might be associated with age and depressive symptoms.

You can find the abstract here.