Effects of dementia on functional decline in patients with non-small cell lung cancer at discharge from acute care hospitals: A retrospective cohort study.

Introduction: Hospital admissions often result in functional decline for patients with dementia, yet evidence on the impact of cancer treatments in this population during hospitalization is limited. We aimed to examine the association between dementia and functional decline after cancer treatment in patients with non-small cell lung cancer (NSCLC).

Materials and methods: A total of 30,213 patients aged 65 years or older hospitalized for NSCLC treatment, from a dataset of 366 acute care hospitals in Japan, were eligible for this study. The primary outcome was activities of daily living (ADL) at discharge, assessed using the Barthel Index, with a total score ranging from 0 to 100, and the secondary outcome was the length of hospital stay. We conducted causal mediation analysis by cancer treatment within a counterfactual framework using the g-formula approach with direct counterfactual imputation. Bias-corrected and adjusted bootstrapped 95 % confidence intervals (CIs) were calculated based on 100 bootstrap samples. Dementia status served as the exposure, ADL scores at admission as the mediator, and ADL scores at discharge as the outcome. Covariates measured at admission were used to adjust for dementia status. Subgroup analyses were performed by treatment group including surgery.

Results: Compared with patients with NSCLC who did not have dementia, those with dementia exhibited lower ADLs at discharge across most cancer treatments, regardless of ADL scores at admission. Patients with dementia who underwent chemotherapy had prolonged hospital stays of 2.90 days longer (95 % CI, 1.27 to 4.52) and lower ADL scores at discharge than their counterparts without dementia (-9.77 [95 % CI, -12.55 to -7.00]). Similarly, patients with dementia who received radiotherapy experienced lower ADL scores at discharge compared with those without dementia (-15.06 [95 % CI, -19.59 to -10.54]), with no difference in the length of hospital stay (-0.54 [95 % CI, -2.84 to 1.75] days). Similar findings were observed from the total effects after adjusting for potential confounders.

Discussion: Patients with comorbid cancer and dementia consistently displayed lower ADL scores at discharge following various cancer treatments. Understanding the effects of dementia on functional decline may aid in making optimal treatment choices for inpatient care for patients with NSCLC.