Individuals with diabetes mellitus can experience overproduction of ketone bodies due to a lack of insulin. Without insulin to help extract glucose from the blood, tissues the levels of malonyl-CoA are reduced, and it becomes easier for fatty acids to be transported into mitochondria, causing the accumulation of excess acetyl-CoA. The accumulation of acetyl-CoA in turn produces excess ketone bodies through ketogenesis.  The result is a rate of ketone production higher than the rate of ketone disposal, and an decrease in blood pH. 
"The whole body 11bHSD1 activity reflects mainly hepatic expression. Initial studies that relied on measurements of cortisol-to-cortisone metabolites in urine (23,36) should be taken with caution as indicative of 11bHSD1 activity, because several other cortisol and cortisone metabolizing enzymes are deregulated in obesity (36). Of greater importance is the finding of reduced hepatic 11bHSD1 activity measured by the conversion of orally administered cortisone to cortisol (23,37). Thus, 11bHSD1 upregulation in obesity seems not to be a generalized process. In both the whole body and the splanchnic circulation there are no differences between obese and lean subjects regarding cortisol regeneration rates (as measured by [2H4]-cortisol tracer), presumably because an upregulation in adipose tissue is counterbalanced by a downregulation in the liver (15).