Confirming the timing of phase-based costing in oncology studies: a case example in advanced melanoma

Abstract

Aims: The utilization of healthcare services and costs among patients with cancer is often estimated by the phase of care: initial, interim, or terminal. Although their durations are often set arbitrarily, we sought to establish data-driven phases of care using joinpoint regression in an advanced melanoma population as a case example.

Methods: A retrospective claims database study was conducted to assess the costs of advanced melanoma from distant metastasis diagnosis to death during January 2010–September 2014. Joinpoint regression analysis was applied to identify the best-fitting points, where statistically significant changes in the trend of average monthly costs occurred. To identify the initial phase, average monthly costs were modeled from metastasis diagnosis to death; and were modeled backward from death to metastasis diagnosis for the terminal phase. Points of monthly cost trend inflection denoted ending and starting points. The months between represented the interim phase.

Results: A total of 1,671 patients with advanced melanoma who died met the eligibility criteria. Initial phase was identified as the 5-month period starting with diagnosis of metastasis, after which there was a sharp, significant decline in monthly cost trend (monthly percent change [MPC] = –13.0%; 95% CI = –16.9% to –8.8%). Terminal phase was defined as the 5-month period before death (MPC = –14.0%; 95% CI = –17.6% to –10.2%).

Limitations: The claims-based algorithm may under-estimate patients due to misclassifications, and may over-estimate terminal phase costs because hospital and emergency visits were used as a death proxy. Also, recently approved therapies were not included, which may under-estimate advanced melanoma costs.

Conclusions: In this advanced melanoma population, optimal duration of the initial and terminal phases of care was 5 months immediately after diagnosis of metastasis and before death, respectively. Joinpoint regression can be used to provide data-supported phase of cancer care durations, but should be combined with clinical judgement.

Keywords:

• Phase of care
• advanced melanoma
• healthcare utilization
• Joinpoint regression
• terminal phase
• cancer care
• phase-based costing

Transparency

Declaration of funding

This study was funded by Bristol-Myers Squibb.

Declaration of financial/other relationships

MA is an employee of Georgetown University and has received consultant fees from Bristol-Myers Squibb. ADC and ME are employees of Xcenda, which has received research funding from Bristol-Myers Squibb for the conduct of this study and for the preparation of this manuscript. SN is a student at the University of Mississippi and was an intern at the time of conduct of this study. KG-S is an employee of Bristol-Myers Squibb. JME peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

Pamela Landsman-Blumberg from Xcenda for strategic oversight and review of the analysis and manuscript, Jasmine Knight from Xcenda for her medical writing services, and StemScientific, an Ashfield Company, for editorial services funded by Bristol-Myers Squibb.

Previous presentation

Nunna S, Coutinho AD, Eaddy M, Landsman-Blumberg P. Use of joinpoint regression to define phases of care from diagnosis of metastases until death in patients with advanced melanoma. Presented at the 21st ISPOR Annual Meeting 2016; Value in Health Vol 19 (3); Pg A6.