Tools for measuring the impact of informal caregiving of the elderly: a literature review

Objectives: (1) Describe available tools to assess the impact of informal caregiving of home-dwelling elderly, (2) identify an acceptable and appropriate tool for a study aiming at the evaluation of the impact of innovative projects for care and support of care for elderly at home, on their main informal caregiver and (3) find a definition of 'main informal caregiver'.

Study design: Literature review by searches of the following electronic databases: MEDLINE, CINAHL, EMBASE, using firstly keywords and exclusion criteria, then citations and reference search.

Results: This review has identified 105 scales assessing the impact of informal caregiving of the elderly. Those scales were described in terms of characteristics of the care receiver population, content and psychometric properties. Most retrieved scales are intended to measure the impact of caregiving on caregivers' health of elderly with dementia (n=49), overall elderly (n=21), cancer patients (n=7), chronically ill patients (n=7), psychiatric patients (n=7) and stroke patients (n=3). Dimensions of the impact of caregiving were classified into its positive (n=34), negative (n=55) or neither positive nor negative (n=16) consequences on the informal caregiver's health. Internal consistency varied from 0.48 to 0.99 and in half of the cases (n=52), construct validity was reported. Scales comprised 1-200 questions. The Zarit Burden Interview (ZBI-12) was selected for the study and an operational definition of the concept of "main informal caregiver" was constructed.

Conclusion: This review identified a large number of scales that can be used to assess the impact of caregiving, viewed through different dimensions. The Zarit Burden Interview can be a useful tool for researchers and clinicians due to its user-friendliness, extensively validation and international use, making comparisons between groups possible. Despite the fact that only the original version of each scale was selected, this inventory should be a useful tool for intervention studies and even clinicians work.