Document Type

Dissertation

Date of Degree

2012

Degree Name

PhD (Doctor of Philosophy)

Degree In

Epidemiology

First Advisor

Elizabeth Chrischilles

Abstract

Urinary incontinence, one of the most prevalent conditions in elderly living in nursing homes (NH) was shown to significantly impact patient's quality of life (QOL) and health outcomes. Bladder antimuscarinics (BAM), the main drug class to treat urinary incontinence, have limited effects in managing the condition; however, given their anticholinergic properties and the characteristics of those living in NH, BAM could potentially lead to serious health consequences in this population.

We conducted a retrospective cohort study with a new-users design by linking existing Veterans Affairs (VA) data (inpatient, outpatient, pharmacy administrative files, and Minimum Data Set- MDS) between fiscal years 2003 and 2009. Potential risks (i.e. fractures and negative impact on cognitive performance) and benefits (i.e. improvement in urinary incontinence, social engagement and overall QOL) associated with initiation of a BAM were assessed in elderly (65+) admitted for long-term care in the VA Community Living Centers.

Descriptive statistics were used to compare BAM new-users and non-users at baseline; in addition, logistic regression was used to identify important predictors of BAM initiation. Treatment selection bias was addressed by using the propensity score matching method. After balancing the groups on baseline characteristics, the risk of fractures (hip fracture, any fracture) in relationship with BAM initiation was evaluated using Cox proportional hazard analysis. BAM impact on the cognitive status measured by the MDS-Cognitive Performance Scale (CPS) was evaluated through generalized estimated equations (GEE) method. Similarly, possible benefits measured through MDS were assessed via GEE.

The final cohort included 1195 BAM new-users (with the majority being prescribed Oxybutynin immediate-release) and 22,987 non-users. Predictors of BAM initiation included demographic characteristics, bladder and bowel continence status, comorbidities, medication use, cognitive performance and functional status.

Our study showed that BAM improved urinary continence (OR=1.27, 95%CI: 1.07-1.50) in those treated; social engagement as measured by MDS-Index of Social Engagement also improved in users, although at a level that is not clinically significant (difference in mean MDS-ISE=0.2074, 95%CI: 0.0550-0.3598). However, BAM initiation increased the risk of fractures (hip: HR=3.69, 95% CI: 1.46 - 9.34, p=0.0059; any fracture: HR=2.64. 95% CI: 1.37 - 5.10, p=0.0039). Our results showed no difference between new-users and non-users with regard to mean CPS and overall QOL.

The purpose of the study was to clarify the proper role of medication use in the management of urinary incontinence in elderly in the VA CLC. The results raise questions about the continued use of Oxybutynin IR, the main BAM prescribed in this population. Given the increased risk for fractures in the context of potential improvement in urinary continence with no clinically significant improvement in social engagement, a wiser step might be to investigate the safety profile for newer BAM for situations when an addition to non-pharmacologic management for urinary incontinence is desired for elderly in long-term care.

Keywords

aging, bladder antimuscarinics, outcomes research, pharmacoepidemiology

Pages

xiii, 188 pages

Bibliography

Includes bibliographical references (pages 173-188).

Copyright

Copyright 2012 Daniela C. Moga

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