"Faith and a sunny day": Association of patient frailty with strain experienced by informal caregivers of older adults with non-muscle-invasive bladder cancer

Introduction: Few studies have evaluated the potential effects of aging-related conditions like frailty in older adults with cancer on informal caregivers. Our objective was to evaluate the association between the sum total of the aging-related conditions of older adults with non-muscle-invasive bladder cancer (NMIBC) and the strain reported by their informal caregivers.

Materials and methods: We conducted an explanatory sequential mixed methods cross-sectional survey study that recruited 81 dyads of older adults with NMIBC (age ≥ 65 at diagnosis) and their informal caregivers. Our outcome was measured by the Caregiver Strain Index (CSI), a self-reported measure of informal caregivers. Our exposure was the patient's deficit accumulation index (DAI), a validated composite measure of frailty derived from a geriatric assessment. A multivariable negative binomial regression was conducted to model CSI. We conducted qualitative thematic content analysis of responses to open-ended survey questions to understand specific types of caregiver strain and to identify coping strategies.

Results: Mean ages of patients and caregivers were 79.4 years and 72.5 years, respectively. Most caregivers were spouses (75.3 %) and lived with the patient (80.2 %). Of patients, 54.3 % were robust, 29.6 % were pre-frail, and 16.1 % were frail. In the multivariable model, we found that patient DAI was significantly associated with CSI (adjusted incidence rate ratio 1.05, 95 % CI 1.02-1.09). The top three sources of strain identified by caregivers were emotional adjustments, medical management, and family adjustments. Coping strategies for each included self-management of emotions, self-education about bladder cancer, and social support, respectively.

Discussion: In this cross-sectional study, we found that worsening frailty in an older adult with NMIBC was associated with greater informal caregiver strain. Informal caregivers reported challenges with emotional management, family dynamics, and medical tasks. These findings may inform longitudinal research and interventions to support informal caregivers who provide care for older adults with NMIBC.