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Background
Laxatives frequently appear in lists of drugs that may lead to falls in the elderly.[1-3] Most often, authors refer to the OASIS (Older Adult Service and Information System) study published in 1991, which evaluated a wide range of drugs and showed that use of laxatives, even after multivariate analysis, is associated with falls (adjusted odds ratio [OR] 2.14 [95% CI 1.02, 4.49]).[4]
Since then, several other studies of iatrogenic falls in the elderly have demonstrated the role of laxatives in falls, as indicated by positive ORs. However, none of these studies attempted to discuss the reasons for this association because the effects of laxatives in this regard were often massively outweighed by those of psychotropic drugs. In fact, two hypotheses can be proposed to explain the link between the use of laxatives and risk of falls. One is an extrinsic mechanical theory: laxative use can increase the urgency to void, resulting in a higher risk of falling while moving to the toilet.[5] The other potential mechanism is an electrolyte imbalance due to excessive or rapid loss of fluids leading to dehydration, orthostatic hypotension or confusion, all of which are well known causes of falls.[6]
The purpose of this study was to identify studies in which the risk factors for falls in the elderly related to laxatives have been evaluated and to conduct a meta-analysis by combining the data from all identified good-quality articles. This strategy allowed us to determine whether the link between falls and laxatives remained, even indirectly, when the statistical power of the data was increased relative to studies in which a smaller number of subjects were evaluated.
Methods
Search Strategy and Selection of Items
A computerized search on the MEDLINE and the Cochrane Collaboration databases was performed for studies published between January 1981 and December 2007 in the English or French languages, using as keywords the two MeSH (Medical Subject Headings) terms 'accidental fall/numerical data' and 'risk factors' combined together; the words 'numerical data' were used to capture articles focusing on quantitative data. Articles were selected if they were original studies that (i) evaluated subjects aged ≥60 years; (ii) identified laxatives as a risk factor for falls (the focus of this study); and (iii) reported on falls occurring in everyday...