As in other forms of diabetes, duration of diabetes and the magnitude of chronic hyperglycemia are probably important determinants of microvascular complications in CFRD. This information is not usually known at the time of presentation of CFRD because of the insidious onset of the disease. Theoretically, CF pulmonary disease, including chronic hypoxia and venous congestion related to pulmonary hypertension, may additionally aggravate microvascular changes. However, the metabolic differences between CFRD and type 1 and type 2 diabetes may also serve to protect CF patients from some diabetes complications. At the time diabetes complications develop, patients with type 1 and type 2 diabetes tend to have concomitant obesity, hypertension, insulin resistance, hyperlipidemia and atherosclerotic cardiovascular disease. These factors, which are generally absent in CF, may contribute to the pathophysiology of microvascular complications in other forms of diabetes.