Age and Health Status Determine Treatment Receipt in Patients with Multiple Myeloma

Background. With the expanding armamentarium of therapeutic agents for multiple myeloma (MM), it is important to identify any untreated or undertreated patient populations. MM is a disease of older adults, with a median age at diagnosis of 66 years. We hypothesized that older patients and those with poorer overall health are less likely to receive treatment. To test this, we performed a retrospective analysis of MM patients in the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database.

Methods. We extracted all MM (ICD-9 code 203.0) cases in the SEER-Medicare database from 2007-2011. Patients were included in this study if they had been continuously enrolled in Medicare Part A, B, and D starting the year prior to diagnosis. The ICD-9 code 203.0 (MM and immunoproliferative neoplasms) captures both active MM and smoldering/asymptomatic myeloma, the former warrants treatment and the latter does not. To identify the population of patients with active MM, we created an algorithm based on ICD-9 codes for different variants of MM defining clinical features, referred to as CRAB criteria [elevated calcium, renal failure, anemia, and bony lytic lesions]. We defined symptomatic MM as either meeting CRAB criteria or receiving chemotherapy within 1 year of diagnosis. The diagnosis and procedure codes for the administration of MM agents were used to differentiate patients who received treatment versus those who did not. Multivariate logistic regression was performed to determine the variables that were independently associated with receipt of treatment. All statistical analyses were performed using SAS Enterprise Guide 5.1. A p value of <.05 was considered statistically significant.

Results.Of the initial 2,871 patients included in the study, 132 patients did not meet CRAB criteria and did not receive any treatment. These 132 patients were considered to have a diagnosis of smoldering/asymptomatic MM, and were excluded from the analyses. Another 89 were excluded due to missing data, leaving 2,650 patients in the final analysis. The median age of the cohort at the time of diagnosis was 75 years old (range 26-99). 52% of patients were female, 77% were Caucasian, 17% African-American, and 7% belonged to other races. 20% of all patients were found to have at least one poor performance indicator; 55% of the cohort at least had one comorbidity based on the Charlson Comorbidity Index (CCI), and 33% were enrolled in Medicaid in addition to Medicare.

Among the 2,650 patients with active MM, 839 (32%) did not receive any systemic treatment. Older age, poor performance indicators, comorbidities, African-American background, and a lower socioeconomic status (SES) were statistically significant factors associated with receipt of no systemic treatment. The risk of not receiving treatment was increased by 4% per year of age (OR 1.04, 95% CI 1.03-1.05), was 29% higher in the presence of poor performance indicators (OR 1.29, 95% CI 1.03-1.60), 17% higher per CCI score increase (OR 1.17, 95% CI 1.11-1.24), 28% higher for patients of African-American descent (OR 1.28, 95% CI 1.01-1.63), and was reduced by 4% per every $10,000 increase in median household income of home census tract (OR 0.96, 95% CI 0.92-0.99).

Conclusions.In this retrospective study of the SEER database, we found that age, health status, race, and SES were predictive of receiving treatment for MM. These factors have previously been linked to reduced utilization of specific treatments for MM, such as stem cell transplants. But, to our knowledge, this is the first study to show their association with the receipt of any MM therapy. Given the advances in MM treatment in the past 2 decades, many with a more favorable toxicity profile compared to conventional chemotherapy, it is critical to investigate and address the barriers to treatment in patients who are less likely to receive the life-prolonging drugs.