OBJECTIVES: The objective of this study was to examine the association between treatment with chemo-immunotherapy and development of mild cognitive impairment or dementia (MCID) in older patients with non-Hodgkin lymphoma (NHL).

METHODS: We conducted a retrospective cohort study using cancer data from the Surveillance, Epidemiology, and End Results (SEER)–Medicare linked database. We identified Medicare beneficiaries with a first primary NHL diagnosis between 2001 and 2011 who survived at least 12 months after NHL diagnosis with no previous history of MCID. Validated algorithms for use with administrative claims data based on International Classification of Diseases, Ninth Revision (ICD-9) and procedural codes were used to identify MCID diagnoses and primary treatment with chemo-immunotherapy during the study period. Fine–Gray regression models, with non-MCID death as a competing risk, were used to estimate subdistribution hazard ratios (sHR).

RESULTS: Among 13,037 older patients with NHL, 221 (1.7%) patients with incident MCID were identified during follow up. The median age of patients with MCID was higher than those without MCID. Compared to patients without MCID, a higher proportion of patients that developed MCID were women, non-white, and had a Charlson score ≥ 2 at NHL diagnosis. Similar proportions of patients with and without MCID received treatment with chemo-immunotherapy. In unadjusted Fine-Gray regression models, exposure to any chemo-immunotherapy was associated with a null risk of MCID (sHR: 1.01; 95% CI: 0.77–1.33); findings were similar in multivariable models (sHR: 0.77, 95% CI: 0.57, 1.03) adjusting for potential confounders. In stratified analyses, chemo-immunotherapy exposure was consistently associated with a decreased risk of MCID regardless of age groups, race, or lymphoma subtype.

CONCLUSIONS: This study suggests chemo-immunotherapy exposure in older patients with NHL is not associated with an increased risk of MCID.