An epidemic of diabetes and the growth of aggressive treatments for the disease over the next two years could prompt a 70 percent increase in spending on therapies, said Medco Health Solutions Inc., a pharmacy benefit management company based in Franklin Lakes, N.J. The company’s new drug trend report said diabetes treatments were the second leading contributor in total dollars to prescription drug spending growth last year, behind cholesterol drugs. Spending on diabetes treatments surged 14.5 percent in 2006, while the use of diabetes treatments increased 5.1 percent.