Willingness to Pay for Inhaled Insulin: A Contingent Valuation Approach

Purpose: To determine the willingness to pay (WTP) of patients with diabetes mellitus for inhaled insulin. Methods: 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 ($Can) using a `payment-scale' method. Results: The mean age of participants was 51.8 years (SD 13.4). Seventy-seven patients had type 2 and 19 had type 1 diabetes. Significantly more participants preferred inhaled insulin over subcutaneous insulin (85 vs 11; p_<_0.01). Mean monthly WTP for inhaled insulin ($Can153.70, SD 99.90) was significantly more than the typical $Can50 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. Conclusion: 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.