The purpose of this study is to estimate the direct costs associated with switching, in either direction, between a rapid-acting analog therapy and short-acting human insulin therapy within the first year following the switch. The additional goals are: 1)to assess the impact of a switch from or to a rapid-acting analog insulin therapy on patient treatment satisfaction, 2) to assess the impact of a switch from or to a rapid-acting analog insulin therapy on patient quality of life, 3) to assess the impact of switch from or to the rapid-acting analog insulin therapy on the quality of metabolic control and, 4) to estimate the total costs (direct and indirect) associated with switching, in either direction between rapid-acting analog and short-acting human insulin within the first year following the switch.