Epidemiology of Faecal Incontinence for People with Dementia Living in the Community in New Zealand: A Retrospective Cohort Study Using interRAI Home Care Assessment Data

Introduction: Globally, there are few studies but wide variation in the epidemiology of faecal incontinence (FI) for people living with dementia in the community. Our objectives are to identify 1-year period prevalence, 5-year incidence, and risks for FI for people living with dementia.

Methods: A retrospective cohort study comprising the International Residential Assessment Instrument Home Care version (interRAI-HC) assessments in a 5-year period in New Zealand (N = 109,964). For prevalence analysis, we selected a dementia cohort for a 1-year period from August 1, 2020, to July 31, 2021 (n = 7,775). For the incidence analysis, participants in the dementia cohort were followed up from the day of the first dementia diagnosis during the period August 1, 2016, and July 31, 2021. Dementia was identified by combining diagnosis of "Alzheimer's disease" and "Dementia other than Alzheimer's disease." Participants were coded with faecal incontinence if they were continent with a stoma, seldom incontinent, occasionally incontinent, often incontinent and incontinent.

Results: One year period (1 August 2020-31 July 2021) prevalence of FI was 26.7% (2,082/7,775) of people with dementia. 5-Year incident FI rate was 19.0 per 100 person-years for people with dementia and 12.3 per 100 person-years for people without dementia. Controlling for risk factors for FI in both groups the hazard ratio for FI was 1.7 for people with dementia.

Conclusion: FI affects a significant proportion of people with dementia in New Zealand. interRAI-HC data could facilitate global epidemiological studies to estimate service or intervention needs for people with dementia to redress or manage FI.