SEER-Medicare Analysis Examines Effects of Comorbidity and Frailty on Prognosis in Older Adults with Chronic Lymphocytic Leukemia

Survival rates in chronic lymphocytic leukemia (CLL) have improved over time with better understanding of disease biology and the introduction of novel therapies. However, researchers who presented at the all-virtual 62nd ASH Annual Meeting & Exposition observed that the survival benefits have been mostly in younger patients.

They decided to examine prognosis for patients with CLL aged 66 years or older. Using information from Surveillance, Epidemiology, and End Results (SEER)-Medicare database, they examined prognosis overall as well as by:

  • Demographics
  • Comorbidities
  • Markers of frailty

Inclusion criteria were patients aged 66 years or older who were diagnosed with CLL between 2004 and 2015 and had continuous enrollment in Medicare Parts A and B and no managed care for a year after diagnosis. The analysis included only patients who survived at least one year after diagnosis. That group included 12,687 patients.

The researchers also identified a subgroup of 1,543 patients who received CLL-directed treatment (treated cohort). Those patients also had to have continuous Medicare Part D in order to be included in the analysis, and they were included in the analysis only if they started treatment within one year of diagnosis.

The researchers followed patients through December 2016 to determine mortality from CLL and all causes, taking into consideration demographics, comorbidity according to the National Cancer Institute Comorbidity Index, and frailty according to a Medicare claims algorithm.

Overall, the mean age at diagnosis was 77 years, and 45% of the patients were female. Regarding frailty, 26% of patients were identified as having a high probability of being frail.

Among the patients, the most common comorbidities were:

  • Uncomplicated diabetes: 25%
  • Chronic pulmonary disease: 17%
  • Congestive heart failure: 14%

Comorbidity levels were as follows:

  • Low: 46%
  • Medium: 26%
  • High: 28%

Analysis of mortality revealed that the 10-year cumulative incidence of mortality was 69% in the overall cohort and 82% in the treated cohort. Most deaths in this patient population were not from CLL. Predictors of worse prognosis were older age at diagnosis, earlier year of diagnosis, higher probability of frailty, and higher comorbidity level.

“CLL-directed treatment decision-making in older adults should explicitly consider age-related health conditions, such as comorbidity and frailty, as they are strongly and independently associated with prognosis,” said lead presenter Emilie Duchesneau of the Department of Epidemiology in the Gillings School of Global Public Health at the University of North Carolina at Chapel Hill.