Cognitive Trajectories in Older Adults Diagnosed With Hematologic Malignant Neoplasms.

IMPORTANCE

More people are surviving long-term after diagnosis with hematologic malignant neoplasm (HMN), yet there are limited data on cancer-related cognitive impairment in people with HMN. Better understanding cognitive outcomes after HMN in older adults is important for patient counseling and management.

OBJECTIVE

To model cognitive trajectories and rates of cognitive decline before and after HMN diagnosis in older adults compared with a matched noncancer cohort.

DESIGN, SETTING, AND PARTICIPANTS: In this population-based cohort study, older adults from the Health and Retirement Study (HRS) diagnosed with HMN between 1998 and 2016 after age 65 years were matched 1:3 to participants without cancer from the same HRS wave using propensity scores incorporating variables relevant to cognition. Cognitive trajectories were modeled with piecewise linear splines, and rates of cognitive decline before, during, and after diagnosis were compared in the 2 groups. Data were analyzed from April 2022 to April 2024.

EXPOSURES

HMN diagnosis by Medicare diagnosis codes.

MAIN OUTCOMES AND MEASURES

Cognitive function was assessed by the Langa-Weir cognitive summary score from 1992 to 2020. Sociodemographic and health-related variables relevant to cognition were incorporated into propensity scores.

RESULTS

At baseline, there were 668 participants in the HMN cohort (mean [SD] age, 76.8 [7.6] years; 343 [51.3%] male; 72 [10.8%] Black, 33 [4.9%] Hispanic, and 585 [87.6%] White) and 1994 participants in the control cohort (mean [SD] age, 76.5 [7.3] years; 1020 [51.2%] male; 226 [11.3%] Black, 91 [4.6%] Hispanic, and 1726 [86.6%] White). The HMN cohort consisted predominantly of more indolent diagnoses, and only 96 patients (14.4%) received chemotherapy. Before and in the 2 years around the time of diagnosis, the HMN and control cohorts had similar rates of cognitive decline. At 1 year postdiagnosis and beyond, the rate of cognitive decline was slower in the HMN cohort (-0.18; 95% CI, -0.23 to -0.14) than in the control group (-0.24; 95% CI, -0.26 to -0.23) (P = .02), but this difference was no longer significant after accounting for the competing risk of death (HMN group, -0.27; 95% CI, -0.34 to -0.19; control group, -0.30; 95% CI, -0.33 to -0.27; P = .48).

CONCLUSIONS AND RELEVANCE

In this cohort study of older adults, the HMN and matched noncancer control cohorts had similar rates of cognitive decline before, during, and after diagnosis after accounting for the competing risk of death.