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Etiology and predictors of urinary incontinence and its effect on quality of life


Dr Doris KY Miu MBBS (HK), MRCP (UK), FHKCP, FHKAM, FRCP (Edin & Glasg), MPH (CUHK), Department of Medicine and Geriatrics, Kwong Wah Hospital, 25 Waterloo Road, Hong Kong, China. Email:


Aim:  Urinary incontinence associated with dementia can result in medical comorbidities. We aimed to determine the prevalence of urinary incontinence and to identify the etiology and factors associated with urinary incontinence in dementia patients.

Methods:  Patients with an Mini-Mental State Examination (MMSE) score of more than 10, attending the memory clinic were recruited. Basic demographic data, types and duration of dementia, use of cholinesterase inhibitor and other drugs with anticholinergic effects, carer stress and presence of urinary incontinence in the previous 6 months were recorded. Urodynamic studies were carried out in those patients with urinary incontinence.

Results:  One hundred and forty-four subjects with a mean age of 78 years (standard deviation 6.8) were included. Forty-eight (33.3%) had urinary incontinence. There was no statistically significant difference between continent and incontinent groups regarding age, MMSE, duration of dementia, use of cholinesterase inhibitor and of drugs with anticholinergic effects. Presence of nocturia of more than twice per night (odds ratio [OR] 4, 95% confidence interval [CI] 1.7, 9.2), use of walking aids (OR 2.6, 95% CI 1.1, 5.9) and male sex (OR 1.36, 95% CI 1.1, 5.2) were independent predictors of urinary incontinence. Urodynamic studies showed that 21 subjects had detrusor overactivity, 13 had bladder outlet obstruction, two with low compliance bladder, two with small bladder capacity, four with detrusor hyperactivity and impaired contractility.

Conclusion:  Urinary incontinence commonly occurs in dementia subjects. Poor mobility and presence of nocturia increase the risk of urinary incontinence. Correction of the possible reversible factors may help to reduce the prevalence of urinary incontinence in patients with dementia and reduce carer stress.