Willingness to pay for inhaled insulin: a contingent valuation approach

To determine the willingness to pay (WTP) of patients with diabetes mellitus for inhaled insulin.

A contingent valuation survey was administered to 96 diabetic outpatients at St. Michael's Hospital, Toronto, Canada. Standardised information about inhaled insulin and subcutaneous rapid-acting insulin was provided via video. Participants' WTP for their preferred product was elicited in Canadian dollars (Can dollars) using a 'payment-scale' method.

The mean age of participants was 51.8 years (SD 13.4). Seventy-seven patients had type 2 and 19 had type 1 diabetes. Significantly more participants preferred inhaled insulin over subcutaneous insulin (85 vs 11; p < 0.01). Mean monthly WTP for inhaled insulin (153.70 Can dollars, SD 99.90) was significantly more than the typical 50 Can dollars per month for subcutaneous insulin (p < 0.01). Significantly more participants with type 2 diabetes using oral drugs than those with type 1 diabetes and using insulin preferred inhaled insulin (98.5% vs 69%, p < 0.001). Diabetic patients who did not use insulin were willing to pay significantly more than were insulin users (p < 0.001). Multiple regression analysis showed that income was significantly associated with WTP for inhaled insulin.

Diabetic patients, particularly those who are not using insulin, indicated that they would prefer inhaled insulin over insulin injection and would be willing to pay a substantial amount per month to use it. An economic evaluation of inhaled insulin would provide important information to healthcare policy decision makers and private payers about its economic value.