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Effectiveness and economic evaluation of a nurse delivered home exercise programme to prevent falls. 1: Randomized controlled trial |
Robertson M C, Devlin N, Gardner M M, Campbell A J |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology The use of a home-based exercise programme, as delivered by a trained district nurse, for preventing falls and injuries among elderly people. The nurse training lasted one week and was held by a research physiotherapist. The intervention consisted of muscle strengthening and balance retraining exercises of progressive difficulty, and a walking plan. All programmes were prescribed individually.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised the general population of men and women aged 75 years and older. Patients unable to walk around their own residence, receive physiotherapy or to understand the trial requirements, were excluded from the study.
Setting The setting was the community. The economic study was carried out in the West Auckland area in New Zealand.
Dates to which data relate Patient enrolment took place in 1998 and lasted for one year (for data on both effectiveness and resource use). The price year was 1998.
Source of effectiveness data The effectiveness evidence came from a single study.
Link between effectiveness and cost data The costing was performed prospectively on the same patient sample as that used in the effectiveness study.
Study sample Power calculations were based on an earlier prospective study. These estimated a reduction from 0.50 to 0.30 in the proportion of patients falling, considering a 20% drop-out rate. The patients were identified from computerised registers at general practices in the study area. Of an initial sample of 590 patients who were invited to participate, 284 chose not to participate, 6 were not eligible, and 60 could not be contacted. Thus, 240 patients were actually included in the study sample. There were 121 individuals in the intervention group and the mean age was 81.1 (+/- 4.5) years. Of these, 55% were aged over 80 years, 33% were men, and 38% had fallen in the previous year). There were 119 patients in the control group and the mean age was 80.8 (+/- 3.8) years. Of these, 50% were aged over 80 years, 32% were men, and 36% had fallen in the previous year.
Study design This was a randomised controlled trial, which was carried out in 17 general practices in the study area. The method of randomisation used random numbers and was carried out in a centre different from that where the whole analysis took place. Over a one-year follow-up period, 8 patients in the intervention group and 11 patients in the control group were lost to follow-up. The assessors who collected and classified the data on falls were blinded to the patients' allocation to the study groups.
Analysis of effectiveness The analysis of the clinical study was conducted on an intention to treat basis. However, it was not stated what outcomes were attributed to the drop-outs. The primary health outcome estimated in the analysis was the number of falls and injuries. The incidence rates, injurious falls and falls requiring medical care were also recorded. Incidence rate ratios were calculated to compare the incidence rates between the intervention and control groups. This was performed through negative binomial regression models, taking into account patient clustering. The SF-12 questionnaire was used to estimate self-perceived health status at entry to the trial. Falls were defined as "unintentionally coming to rest on the ground, floor, or other lower level" and were monitored for one year by asking participants to return pre-addressed and pre-paid postcard calendars every month. Fall events were classified as serious, moderate, and no injury. Serious falls were those resulting in fracture, admission to hospital with injuries, or a requirement for stitches. Moderate falls were those where patients required medical help, or where bruising, sprains, cuts, abrasions, or a reduction in physical function of at least three days occurred. Compliance was evaluated using postcard calendars similar to those used to monitor falls. The study groups appear to have been comparable at baseline, although there was no statistical comparison. More participants from the intervention group than the control group completed the trial (difference 11%, 95% confidence interval, CI: 3 - 19).
Effectiveness results After a mean follow-up period of 10.9 months in the control group and 11.6 months in the intervention group (p=0.028), the number of falls was 109 in the control group and 80 in the intervention group. In the sub-group analysis, there was a significant reduction in the number of falls for those aged 80 or over, (p=0.007) and there was no difference for participants aged 75 to 79 years.
The resulting incidence ratio was 0.54 (95% CI: 0.32 - 0.90; P=0.019). This meant that, during the trial, there was a 46% reduction of falls in the intervention group compared with the control group.
The falls per 100 person years were 100.6 in the control group and 68.5 in the intervention group.
The number of injurious falls was 49 (9 serious and 40 moderate) in the control group and 42 (2 serious and 40 moderate) in the intervention group. The relative risk for serious injuries was 4.6% (95% CI: 1.0 - 20.7).
The injurious falls per 100 person years were 45.2 in the control group and 36.0 in the intervention group.
The number of falls requiring medical care was 26 (24%) in the control group and 18 (23%) in the intervention group.
Clinical conclusions The effectiveness study showed that the nurse-delivered home exercise programme was more effective than standard care in reducing the occurrence of falls in elderly people.
Measure of benefits used in the economic analysis The benefit measure used in the economic analysis was the number of falls occurring in the study groups.
Direct costs No discounting was applied since the time horizon of the analysis was one year. The unit costs were reported separately from the quantities of resources and a detailed breakdown of the costs was given. The health services included in the analysis were the training course costs, recruitment, programme prescription, follow-up costs, supervision programme costs (time for the physiotherapist and exercise nurse), overhead costs, and hospitalisation due to falls. The training course costs were for nurse and physiotherapist time, accommodation and materials. The follow-up costs were for the general practitioner and nurse's time, telephone calls and postage. The research costs were not included in the economic evaluation. The cost/resource boundary adopted in the study was unclear. The resource use was estimated from data collected alongside the clinical trial, while the unit costs were estimated from actual data such as hospital and trial records. The costs were estimated for 1998 to 1999 and 1998 prices (exclusive of government goods and service tax) were used.
Statistical analysis of costs The costs were treated deterministically.
Indirect Costs The indirect costs were considered to be zero since the exercises were assumed to take place during the patients' leisure time.
Currency New Zealand dollars (NZ$). The average exchange rate in 1998 was NZ$1 = 32 p.
Sensitivity analysis One-way sensitivity analyses were conducted to assess the robustness of the estimated cost-effectiveness ratios to variations in baseline costs. These were conducted using the 125th and the 75th percentiles of the total programme costs, assuming that training and supervision took place in the same centre (then excluding both travel and accommodation costs). Also, using the 125th percentile of home visit costs, quadrupling the ankle cuff weight costs, assuming no extra overhead costs, with and without hospital costs averted. The analysis was also performed considering only the sub-group of patients aged 80 years and older.
Estimated benefits used in the economic analysis See the 'Effectiveness Results' section.
Cost results The costs of implementing the programme were NZ$52,229 or NZ$432 per person. The costs resulting from falls (hospitalisation) were observed only in the control group (5 patients). Thus, the hospitalisation costs averted with the programme were NZ$47,818.
Synthesis of costs and benefits An incremental cost-effectiveness ratio was calculated to combine the costs and benefits of the exercise programme in addition to standard care, compared with standard care alone.
The incremental cost per fall prevented was NZ$1,803 (adjusted ratio, using fall events per 100 person years: NZ$1,629) when only exercise programme costs were included and NZ$155 (adjusted ratio: NZ$140) when the hospital costs averted were also considered.
The incremental cost per injurious fall prevented was NZ$7,471 (adjusted ratio: NZ$5,685) when only exercise programme costs were included and NZ$640 (adjusted ratio: NZ$487) when the hospital costs averted were also considered.
The sensitivity analyses showed that the cost-effectiveness ratio of the exercise programme was very low, especially when the hospital costs averted were considered. In the sub-group analysis of patients aged at least 80 years, the programme led to cost-savings.
Authors' conclusions The home exercise programme aimed at preventing falls, and delivered by a trained nurse from within home health services, was more effective than standard care for elderly people since it was cost-saving for patients aged at least 80 years.
CRD COMMENTARY - Selection of comparators The rationale for the choice of the comparators was clear. Standard care alone was selected as it represented the routine care for elderly patients. You should decide whether it represents a valid comparator in your own setting.
Validity of estimate of measure of effectiveness The analysis of the effectiveness used a randomised controlled trial, which was appropriate for the study question. The study sample was representative of the study population. The methods of randomisation and patient enrolment were reported. Power calculations were based on an earlier prospective study. The length of follow-up and the proportions of patients who remained in the study were reported. The study groups appear to have been comparable at baseline. The basis of the analysis was intention to treat. This further enhances the internal validity of the analysis, although the outcomes attributed to the drop-outs were not reported. How the drop-outs were treated is important because there was a higher number of drop-outs for the control group than for the intervention group. The authors suggest that this may be related to the risk of falling. Statistical analyses were also conducted in the effectiveness study, which was partially blind.
Validity of estimate of measure of benefit The benefit measure used in the economic analysis was the number of falls. This was estimated in the effectiveness study. No measures of utility and patient satisfaction were used, although these would have been helpful.
Validity of estimate of costs The perspective adopted in the study was societal. The costs and resource use were reported in detail, as was the price year, thus facilitating reflation exercises in other settings. Although the costs were treated deterministically in the base-case analysis, several sensitivity analyses were conducted to estimate the robustness of the cost-effectiveness ratios. Resource use was evaluated prospectively alongside the clinical trial. The source of cost data was reported. The authors acknowledged that the costs might differ depending on the study setting.
Other issues The authors made some comparisons of their findings with those from published studies. The authors did not explicitly address the issue of the generalisability of the study results to other settings. However, several sensitivity analyses were performed on the cost side of the analysis, thus enhancing the external validity of the study. The study referred to the general population of elderly people and this was reflected in the conclusions of the analysis.
Implications of the study The main implication is that trained nurses from within home health services safely and efficiently delivered the home exercise programme aimed at preventing falls in both elderly men and women. The study demonstrated the effective collaboration between researchers, public health professionals and administrators. The authors suggested that nurses should be trained and supervised by a suitably qualified physiotherapist.
Source of funding Funded by the Health Funding Authority Northern Division, New Zealand; the Accident Rehabilitation and Compensation Insurance Corporation of New Zealand; and the Trustbank Otago Community Trust.
Bibliographic details Robertson M C, Devlin N, Gardner M M, Campbell A J. Effectiveness and economic evaluation of a nurse delivered home exercise programme to prevent falls. 1: Randomized controlled trial. BMJ 2001; 322: 697-701 Indexing Status Subject indexing assigned by NLM MeSH Accidental Falls /economics /prevention & Aged; Aged, 80 and over; Cost-Benefit Analysis; Exercise Therapy /methods; Female; Home Care Services /economics; Humans; Male; Nursing Care /methods; control AccessionNumber 22001008053 Date bibliographic record published 31/07/2003 Date abstract record published 31/07/2003 |
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