OBJECTIVES:

Seasonal variation in disease incidence, screening, and diagnosis has been extensively reported and impacts treatment initiation. However, budget impact analyses typically assume that patients initiate treatment at the start of each year. We explored whether accounting for fluctuations in patient entry timing affects budget impact projections.

METHODS:

We developed a budget impact model in Microsoft Excel® using dummy data to test different patient entry patterns: yearly intervals (Scenario 1); weekly intervals assuming even distribution throughout the year (Scenario 2); and weekly intervals assuming 70% of entries in winter, spring, summer, and fall months (Scenario 3–Scenario 6, respectively). 150–250 patients initiate treatment each year and are followed up in weekly cycles. The post-launch uptake of the hypothetical intervention is 10% in Year 1, 30% in Year 2, and 50% in Year 3. The intervention is administered every 2 weeks ($150/administration; 1.15% weekly discontinuation probability), and the comparator is administered every 3 weeks ($250/administration; 1.72% weekly discontinuation probability). Following discontinuation of the intervention or comparator, patients receive subsequent treatment.

RESULTS:

The direction of the budget impact (negative/cost saving or positive/cost increase) varies between years and scenarios. The 3-year cumulative budget impact for all weekly entry scenarios (Scenario 2–Scenario 6) is less than half of that in the standard yearly entry scenario (Scenario 1): $28,045, $8,615, $14,018, $13,129, $5,627, and $2,148 for Scenario 1 through Scenario 6, respectively.

CONCLUSIONS:

The pattern of patient entry affects budget impact estimates, with the potential to distort reimbursement decisions and price negotiations. With increased access to real-world data, clinical and diagnostic treatment patterns can be reviewed and modelled based on electronic health records and claims data – including, for example, the number of patients diagnosed, the time from diagnosis to treatment, and the treatments provided in a population.