DPP-4 inhibitors, such as Januvia and Onglyza, now account for 21 percent of treatments. Long-acting insulins, such as Lantus and Levemir, also saw an increase from nearly negligible in 1997 to 18 percent in 2012. Short-acting insulins, like Novolog, Humalog, and Apidra, have increased modestly.

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