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PAPERS: Terry P Haines, Kim L Bennell, Richard H Osborne, and Keith D Hill Effectiveness of targeted falls prevention programme in subacute hospital setting: randomised controlled trial BMJ 2004; 328: 676 [Abstract] [Full text]

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Community Falls Assessment

Sudarshini Ramanathan, Steven Tongson, Nicholas Collins, and Stephen Wilson   (8 April 2004)

Are all falls equal?

Meghan G. Donaldson, Boris Sobolev, Associate Professor, Dept. of Health Care and Epidemiology, Univeristy of British Columbia   (13 May 2004)

Re: Are all falls equal?

Terry P Haines, Kim L Bennell, Richard H Osborne, and Keith D Hill   (9 June 2004)

Community Falls Assessment 8 April 2004
Sudarshini Ramanathan, Medical Student Macarthur Health Service - Ambulatory Care, Steven Tongson, Nicholas Collins, and Stephen Wilson Send response to journal: Re: Community Falls Assessment	A randomised controlled trial performed by Haines et al (1) assessed the role of a targeted, multiple intervention; falls prevention program in a subacute hospital setting. The conclusion reached was that multiple interventions including an exercise program, education, and the use of hip protectors compared to usual care, significantly reduced the incidence of morbidity associated with falls in such a setting. One third of elderly people living in the community experience a fall contributing to disability, loss of independence and function, and overall wellbeing (2, 3). This is a strong indication for the implementation of interventions targeting at risk individuals in the context of the community itself, rather than only targeting those already within the hospital system. Hill et al indicate that community-based falls prevention programs are more effective than institution-based studies (3). One such program is outlined in a study by van Haastregt et al (4) where participants in the community aged 70 or over who had reported two or more falls in the previous six months were visited by a community nurse on multiple occasions. Visits involved screening for medical, environmental and behavioural factors including mobility, difficulty in activities of daily living, co-morbidities, medication, cognitive functioning, and home safety. Individual assessments were then made and recommendations included home adjustments, provision of aids and devices, and appropriate referrals. Secondary benefits included the nursing liaison between the individual and different disciplines of health care professionals, and the detection of previously untreated problems in the context of the home visits. By identifying individuals at an increased risk of having a fall and implementing preventative strategies at a community level, there would be a significant reduction in morbidity and mortality associated with falls in the elderly, as well as a reduction in associated healthcare costs (5). This could include a post-fall assessment and systematic risk factor screening, an exercise program which targets endurance, balance, gait and strength; home visits and recommended environmental modifications, and the provision of educational brochures regarding risk factors. Exercise programs and education could feasibly target the general population of elderly individuals, rather than only being reserved for those who are in an acute or subacute hospital setting (2). A further point raised by the article in question is the need for multidisciplinary participation in the assessment and primary prevention of falls in the elderly. This focused on the expertise of physiotherapists or occupational therapists. However, it would appear to be advantageous to adopt a multidisciplinary approach and involve community nurses, social workers, pharmacists, and other allied health professionals in the assessment of those at risk, and use their varied expertise and tailor recommendations to each individual in order to maximise their function and independence (4). References 1. Haines TP, Bennell KL, Osborne RH, Hill KD. Effectiveness of targeted falls prevention programme in subacute hospital setting: randomised controlled trial. British Medical Journal. 2004; 328: 676. 2. Herwaldt LA, Pottinger JM. Preventing falls in the elderly. Journal of the American Geriatrics Society. 2003; 51: 1175-1177. 3. Hill-Westmoreland EE, Soeken K, Spellbring AM. A meta-analysis of fall prevention programs for the elderly. Nursing Research. 2002; 51(1):1-8. 4. Haastregt JCM, van Rossum E, Diederiks JPM, de Witte LP, Voorhoeve PM, Crebolder HFJM. Process-evaluation of a home visit programme to prevent falls and mobility impairments among elderly people at risk. Patient Education and Counseling. 2002; 47: 301-309. 5. Chang JT, Morton SC, Rubenstein LZ, Mojica WA, Maglione M, Suttorp MJ, Roth EA, Shekelle PG. Interventions for the prevention of falls in older adults: systematic review and meta-analysis of randomised clinical trials. British Medical Journal. 2004; 328: 680. Competing interests: None declared
Are all falls equal? 13 May 2004
Meghan G. Donaldson, PhD Candidate Dept. of Health Care and Epidemiology, University of British Columbia, Vancouver BC, V6T 1Z3, Boris Sobolev, Associate Professor, Dept. of Health Care and Epidemiology, Univeristy of British Columbia Send response to journal: Re: Are all falls equal?	EDITOR- We would like to congratulate Haines and colleagues on their recent article about a successful multifactorial intervention to prevent falls in the subacute hospital setting [1]. This study provides strong evidence that falls can be prevented in this clinically important population. Haines et al. calculated the average number of falls for increasing study periods using the Nelson-Aalen estimator in the context of recurrent failure time data [2]. Developed in the reliability literature, this method utilizes two assumptions which may or may not be appropriate for studying consecutive falls. First, the method does not distinguish between falls occurring among individuals with a prior fall and falls occurring among those without prior falls. It assumes that multiple failure events are identical for each individual, as if at every fall individuals were to be “replaced” by themselves with the same cumulative time at risk. Second, an underlying statistical model assumes no correlation between multiple failure times related to the same individual, which means that susceptibility of the individual does not change with falls. Several authors argued for the conditional approach that distinguishes between first and recurrent events [3] [4]. It estimates the rate of k-th events among those who have already experienced (k-1) events. This approach addresses the issue of constant susceptibility in a more natural way than marginal models [2] [3]: while the association between event times remains unspecified, the event-specific rate functions condition on having had previous events. If the rate functions for later events are similar, then consecutive falls may be analyzed by Nelson-Aalen cumulative mean function [5]. 1. Haines, T.P., et al., Effectiveness of targeted falls prevention programme in subacute hospital setting: randomised controlled trial. British Medical Journal, 2004. 328(7441): p. 676. 2. Therneau, T.M. and P.M. Grambsch, Modeling Survival Data: Extending the Cox Model. Statistics for Biology and Health. 2000, New York: Springer. 3. Pepe, M.S. and J. Cai, Some graphical displays and marginal regression analyses for recurrent failure times and time dependent covariates. Journal of the American Statistical Association, 1993. 88(423): p. 811-820. 4. Oakes, D., Frailty models for multiple event times, in Survival Analysis, State of the Art, J.P. Klein and P.K. Goel, Editors. 1992: Kluwer, Netherlands. 5. Nelson, W., Recurrent-events data analysis by product repairs; disease episodes and other applications. ASA-SIAM: Statistics and Applied Probability. 2002, Philadelphia: Society for Industrial and Applied Mathematics. Competing interests: None declared
Re: Are all falls equal? 9 June 2004
Terry P Haines, PhD Candidate University of Melbourne, Australia 3010, Kim L Bennell, Richard H Osborne, and Keith D Hill Send response to journal: Re: Re: Are all falls equal?	EDITOR – We thank Donaldson et al (2004) for their contribution to the continuing debate regarding appropriate approaches for the analysis of falls data. Development and implementation of appropriate methods for analysing event rate data for recurrent events is an area of much recent focus and considerable controversy in statistics literature. A concern in addressing this data is that of data dependence, where the observed frequency of the event may depend on the history of previous events within that individual. Several different approaches have been described, including measures of proportions, counts, and survival times, each with different ways of accounting for event dependence.1 The primary analysis presented in our paper,2 which examined the effectiveness of a falls prevention program in the subacute hospital setting, employed a logrank statistic for recurrent events.3 This approach was developed as an analogue of the non-parametric logrank statistic for time to first events. This approach also, along with some other approaches, avoids the problem of specifying the dependence structure among recurrent events.4 Donaldson et al (2004) suggests a conditional Cox proporitonal hazards model may have been a more appropriate approach to analyse our data.5 This approach does have advantages, however it may be difficult to apply in studies such as ours. It considers only those participants who have experienced an equivalent number of events in the same “risk set”. Many patients have falls prior to hospital admission, during their acute hospitalisation, and even in the period between admission to subacute care and consent to participate in a trial in a subacute hospital. Using a conditional approach we would have had to decide if all patients started at “zero” falls at the commencement of their observation in our study. For us to do so would clearly have been unrealistic for several patients. Ignoring these falls would also have meant that the recurrent events observed in our study would have been assumed to be independent of previous events.4 Alternately, attempting to measure the number of falls each study participant had prior to their participation in our study would have been unrealistic. Humans tend to commence falling at a very early age, and may continue to have falls throughout their early and middle adulthood. Even using an estimate of the number of falls since turning 65 years (an arbitrary point admittedly) would be difficult considering the level of cognitive impairment of participants in our study. There have been many analysis approaches described that could be applied to falls research data with both positive and negative aspects regarding their application. REFERENCES 1. Sturmer T, Glynn R, Kliebsch U, Brenner H. Analytic strategies for recurrent events in epidemiologic studies: Background and application to hospitalization risk in the elderly. Journal of Clinical Epidemiology 2000; 53: 57-64. 2. Haines T, Bennell K, Osborne R, Hill K. Effectiveness of targeted falls prevention programme in subacute hospital setting: Randomised controlled trial. British Medical Journal 2004; 328: 676-679. 3. Pepe M, Cai J. Some graphical displays and marginal regression analyses for recurrent failure times and time dependent covariates. Journal of the American Statistical Association 1993; 88: 811-820. 4. Miloslavsky M, Kele S, van der Laan M. Recurrent events analysis in the prescence of time-dependent covariates and dependent censoring. Journal of the Royal Statistical Society Series B 2004; 66: 239-. 5. Donaldson M, Sobolev B. Are all falls equal? British Medical Journal 2004; 328: Rapid response. Competing interests: None declared