Cost and Resource Use Studies| Volume 23, SUPPLEMENT 1, S4-S5, May 01, 2020

# CR1 PHASE-SPECIFIC AND LIFETIME COSTS OF MULTIPLE MYELOMA (MM) AMONG ELDERLY PATIENTS IN THE UNITED STATES

Open Archive

## Objectives

This study aimed to estimate lifetime costs and phase-specific costs of MM, and identify cost drivers among elderly MM patients enrolled in fee-for-service Medicare.

## Methods

A retrospective cohort study was conducted using 2006-2016 SEER-linked Medicare administrative claims data. Newly diagnosed MM patients were matched to non-cancer beneficiaries on months of eligibility and death date/date of loss of eligibility. The index date for the non-cancer group was the MM diagnosis date of the matched MM patient. Costs attributable to MM were calculated for the following 4 phases: pre-diagnosis (3 months prior to diagnosis), initial, continuous, and terminal. Continuous phase was defined as any time spent between the initial and terminal phases. Duration of the initial and terminal phases were estimated using Joinpoint regression analysis. Survival time was taken into account to compute the lifetime and phase-specific costs. All costs attributable to MM were estimated controlling for clinical and socio-demographic characteristics at baseline. Generalized linear models with log link and gamma distribution were used to assess incremental MM costs and recycled predictions were used to account for covariate imbalance.

## Results

A total of 9,066 Medicare beneficiaries were included – 4,533 MM patients and 4,533 matched non-cancer beneficiaries. Joinpoint regression estimated the initial phase to be the first 4 months post diagnosis, and the terminal phase to be the last 3 months prior to death. Mean lifetime costs attributable to MM were $184,494. Mean PMPM phase-specific costs of MM were estimated to be$1,244, $11,181,$5,634, and \$6,280 for the pre-diagnosis, initial, continuous, and terminal phases respectively. Across all phases, outpatient and inpatient costs were the major cost drivers, followed by pharmacy costs.

## Conclusions

This study highlights the substantial economic burden associated with MM in the US, and cost variation by phase of care. These estimates will help inform future resource allocation and policy decisions.