Incremental cost per QALY analysis The incremental cost of orlistat plus a calorie-controlled diet vs calorie-controlled diet alone (placebo) is estimated in the following steps:
The acquisition cost of orlistat is calculated for orlistat responders and non responders and for calorie-controlled diet alone (placebo).
The diabetes-related savings are calculated for orlistat responders and nonresponders alone.
The weighted average cost of an average orlistat patients is calculated using known percentages of responders and nonresponders and cost data from steps (i)–(ii), in addition to adding the cost of the dietary programme.
The cost of an average patient on a calorie-controlled diet (placebo) is calculated using data on diabetes savings and cost of dietary programme.
The incremental cost is obtained from the difference in average costs between orlistat plus calorie-controlled patients and calorie-controlled diet alone (placebo) patients.
In the final step, the incremental cost per QALY is calculated as follows: Incremental cost of orlistat plus calorie-controlled diet less calorie-controlled diet only (placebo) / incremental QALYs associated with orlistat plus calorie-controlled diet less QALYs associated with calorie-controlled diet alone (placebo).