The prognosis for patients with chronic lymphocytic leukemia (CLL) has seen recent improvements, but these benefits largely appear to affect younger patients, with more modest benefits observed among older adults. A study evaluated the prognosis for older adults by comorbidities and frailty, using Medicare data. The results were presented at the 62nd ASH Annual Meeting & Exposition.
The researchers queried Surveillance, Epidemiology, and End Results-Medicare data on adults aged ≥66 years diagnosed with CLL from 2004 through 2015. Patients were then divided into two cohorts, one of which initiated CLL-directed therapy after diagnosis. Both groups had to be continuously enrolled in Medicare Parts A and B and have no managed care for the one-year period after their diagnosis. Patients in the treated cohort who started treatment on or after January 1, 2007, had to also be continuously enrolled in Medicare Part D. The researchers utilized a landmark approach, in which only patients who survived at least one year after their CLL diagnosis (the landmark) were assessed.
For comorbidity, patients were classified as low, medium, or high per the National Cancer Institute Comorbidity Index, and for frailty, Medicare claims algorithms in the year between diagnosis and the landmark (one year following diagnosis) were used.
Of the 12,687 total patients with CLL, 1,543 were in the treated group. In the overall cohort, the mean age at diagnosis was 77 years, and 45% of patients were female; these patients were classified as low (46%), medium (26%), and high (28%) comorbidity. The most prevalent comorbidity was uncomplicated diabetes (25%), followed by chronic pulmonary disease (17%) and congestive heart failure (14%). A high probability of frailty—defined as ≥10%—was observed in 26% of patients.
The overall cohort had a lower 10-year cumulative incidence of mortality from the landmark compared with the treated group (69% [95% confidence interval (CI), 67-70] vs. 82% [95% CI, 79-85]). Most deaths were due to non-CLL causes. When looking at the entire cohort, factors associated with worse prognosis were older age at diagnosis, earlier year of diagnosis, higher predicted frailty, and higher comorbidity. The relationships between frailty and comorbidity and CLL-specific mortality were not as significant as those between frailty and comorbidity and other-cause mortality; similar observations were made in the treated group. When adjusting for comorbidity level, frailty was still correlated with mortality.
“Most older adults diagnosed with CLL die from non-CLL causes. 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,” the study authors concluded.