Cost-benefit analysis of fall injuries prevented by a programme of home modifications: a cluster randomised controlled trial.

BACKGROUND: Injuries due to falls in the home impose a huge social and economic cost on society. We have previously found important safety benefits of home modifications such as handrails for steps and stairs, grab rails for bathrooms, outside lighting, edging for outside steps and slip-resistant surfacing for outside areas such as decks. Here we assess the economic benefits of these modifications. METHODS: Using a single-blinded cluster randomised controlled trial, we analysed insurance payments for medically treated home fall injuries as recorded by the national injury insurer. The benefits in terms of the value of disability adjusted life years (DALYs) averted and social costs of injuries saved were extrapolated to a national level and compared with the costs of the intervention. RESULTS: An intention-to-treat analysis was carried out. Injury costs per time exposed to the modified homes compared with the unmodified homes showed a reduction in the costs of home fall injuries of 33% (95% CI 5% to 49%). The social benefits of injuries prevented were estimated to be at least six times the costs of the intervention. The benefit-cost ratio can be at least doubled for older people and increased by 60% for those with a prior history of fall injuries. CONCLUSIONS: This is the first randomised controlled trial to examine the benefits of home modification for reducing fall injury costs in the general population. The results show a convincing economic justification for undertaking relatively low-cost home repairs and installing safety features to prevent falls. TRIAL REGISTRATION NUMBER: ACTRN12609000779279.

Home modifications to reduce injuries from falls in the home injury prevention intervention (HIPI) study: a cluster-randomised controlled trial.

BACKGROUND: Despite the considerable injury burden attributable to falls at home among the general population, few effective safety interventions have been identified. We tested the safety benefits of home modifications, including handrails for outside steps and internal stairs, grab rails for bathrooms, outside lighting, edging for outside steps, and slip-resistant surfacing for outside areas such as decks and porches. METHODS: We did a single-blind, cluster-randomised controlled trial of households from the Taranaki region of New Zealand. To be eligible, participants had to live in an owner-occupied dwelling constructed before 1980 and at least one member of every household had to be in receipt of state benefits or subsidies. We randomly assigned households by electronic coin toss to either immediate home modifications (treatment group) or a 3-year wait before modifications (control group). Household members in the treatment group could not be masked to their assigned status because modifications were made to their homes. The primary outcome was the rate of falls at home per person per year that needed medical treatment, which we derived from administrative data for insurance claims. Coders who were unaware of the random allocation analysed text descriptions of injuries and coded injuries as all falls and injuries most likely to be affected by the home modifications tested. To account for clustering at the household level, we analysed all injuries from falls at home per person-year with a negative binomial generalised linear model with generalised estimating equations. Analysis was by intention to treat. This trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12609000779279. FINDINGS: Of 842 households recruited, 436 (n=950 individual occupants) were randomly assigned to the treatment group and 406 (n=898 occupants) were allocated to the control group. After a median observation period of 1148 days (IQR 1085-1263), the crude rate of fall injuries per person per year was 0.061 in the treatment group and 0.072 in the control group (relative rate 0.86, 95% CI 0.66-1.12). The crude rate of injuries specific to the intervention per person per year was 0.018 in the treatment group and 0.028 in the control group (0.66, 0.43-1.00). A 26% reduction in the rate of injuries caused by falls at home per year exposed to the intervention was estimated in people allocated to the treatment group compared with those assigned to the control group, after adjustment for age, previous falls, sex, and ethnic origin (relative rate 0.74, 95% CI 0.58-0.94). Injuries specific to the home-modification intervention were cut by 39% per year exposed (0.61, 0.41-0.91). INTERPRETATION: Our findings suggest that low-cost home modifications and repairs can be a means to reduce injury in the general population. Further research is needed to identify the effectiveness of particular modifications from the package tested. FUNDING: Health Research Council of New Zealand.

Value of statistical life: adults versus children.

Most studies on the value of statistical life (VOSL) and values for prevention of injuries provide only the average values for the overall population. It is often argued that the values for children may be higher than that for adults because parents are usually more concerned about the mortality and morbidity risks of their children than for themselves. However, it is not an easy task to determine separate VOSLs for children and adults. Only a few empirical results are available and they do not show a definite pattern. Using the results of a value of safety survey carried out in New Zealand in 1997-1998, this paper investigates whether the willingness to pay based VOSL is higher or lower for children. Formal statistical tests were carried out to test the differences and also a regression analysis was carried out to estimate the VOSL separately for adults and children, particularly in households with children. The analysis shows that for the whole sample, the value is higher for children. However, when some outliers were removed the results indicate a higher value for adults than for children. A further trimming shows the value of children is slightly higher. Therefore, no definite conclusion could be drawn. Households without children have the highest VOSL.

An evaluation of a supplementary road safety package.

A Supplementary Road Safety Package (SRSP) was developed in New Zealand in 1995/1996 to supplement the compulsory breath test (CBT) and speed camera programmes introduced in 1993. A major feature of the package was the use of emotion and shock advertising campaigns not only to affect high risk driving attitudes and behaviours towards speeding and drink-driving but also to encourage the use of safety belts. Furthermore, the SRSP also emphasised targeting enforcement to these three areas. This package continued for 5 years. This paper estimates the effect of the package on road trauma. The analysis shows that the Package made substantial impact on road safety and saved over 285 lives over the 5-year period.

Alcohol in New Zealand road trauma.

Alcohol-impaired driving is one of the major contributing factors to fatal and serious crashes in New Zealand. To curb the high level of road trauma resulting from drink-driving, a compulsory breath test (CBT) programme was introduced in 1993 and a supplementary road safety package (SRSP) in 1995/1996. The SRSP aimed to enhance road safety enforcement and advertising activities, and focused primarily on drink-driving and speeding. These interventions have resulted in a substantial reduction in alcohol-related road trauma. Subsequently, in 1999, the drinking age was lowered from 20 to 18 years. This paper examines the impacts of these drink-driving interventions. The analysis shows that the CBT programme and the SRSP have contributed to the reduction in alcohol-related crashes in recent years. There is also some evidence that, following the lowering of the drinking age, there has been an increase in drink-driving and subsequent alcohol-related crash involvement for drivers under 18 years.

Formulating a programme of repairs to structural home injury hazards in New Zealand.

Home injuries are a substantial health burden worldwide, with the home setting being at least as important as the road for injury. Focusing on common injury hazards presented by the home environment, we sought to examine the justification for significant expenditure on safety-related repairs to the housing stock. Trained inspectors assessed 961 New Zealand houses for injury hazards. Using administrative data from the Accident Compensation Corporation (the national injury insurance agency), 1328 home injuries were identified amongst the 1612 occupants of these houses over the 2006-2009 period. Telephone interviews gathered data on the location and nature of these injuries, and the attitudes of those injured to potential injury hazards in their homes. Commonly occurring injury hazards that could be repaired at modest cost were identified based on their prevalence estimated by the housing inspection, and their location with respect to the areas of the home where the injuries occurred (identified during the telephone interviews). About 38% of the home injuries studied were potentially related to a structural aspect of the home environment. Common safety hazards included the lack of working smoke detectors (65% of the sample), inadequately fenced driveways (55%), hot water temperatures measured at over 60° (49%) and poorly lit access to the house (34%). A protocol for identifying and repairing important common hazards was designed. The actual safety effects of this protocol are in the process of being examined in a randomised controlled trial.

Estimation of the social costs of home injury: a comparison with estimates for road injury.

Home injury is thought to constitute a major health burden in most developed countries. However, efforts to address this burden have been hampered by reluctance from outside agencies to interfere with the home environment of individuals, even if it benefits the occupant's safety. This paper outlines cost-benefit evaluation methods established in the transport safety domain applied to home safety to estimate the social cost of unintentional home injury in New Zealand. Estimates of costs imposed on society by home injury can provide an important motivator for initiating research and programmes to reduce home injury risk. Data sources used included mortality data, hospitalisation data and data on minor injuries that required medical treatment, but not hospital admission. We estimated that unintentional home injuries in New Zealand impose an annual social cost of about $NZ 13 billion (about $US 9 billion), which is about 3.5 times the annual social cost of road injury. These estimates provide a rational evidence base for decisions on housing-focused safety regulation or interventions that always carry some cost, and therefore need to be weighed against the benefits of injuries potentially prevented.