Cost-effectiveness of a back school intervention for municipal employees

Systematic Review of Costs and Effects of Self-Management Interventions for Chronic Musculoskeletal Pain: Spotlight on Analytic Perspective and Outcomes Assessment

BACKGROUND

Evidence for the cost-effectiveness of self-management interventions for chronic musculoskeletal pain (CMP) lacks consensus, which may be due to variability in the costing methods employed.

PURPOSE

The purposes of the study were to identify how costs and effects have been assessed in economic analysis of self-management interventions for CMP and to identify the effect of the chosen analytical perspective on cost-effectiveness conclusions.

DATA SOURCES

Five databases were searched for all study designs using relevant terms.

STUDY SELECTION

Two independent researchers reviewed all titles for predefined inclusion criteria: adults (≥18 years of age) with CMP, interventions with a primary aim of promoting self-management, and conducted a cost analysis.

DATA EXTRACTION

Descriptive data including population, self-management intervention, analytical perspective, and costs and effects measured were collected by one reviewer and checked for accuracy by a second reviewer.

DATA SYNTHESIS

Fifty-seven studies were identified: 65% (n = 37) chose the societal perspective, of which 89% (n = 33) captured health care utilization, 92% (n = 34) reported labor productivity, 65% (n = 24) included intervention delivery, and 59% (n = 22) captured patient/family costs. Types of costs varied in all studies. Eight studies conducted analyses from both health service and societal perspectives; cost-effectiveness estimates varied with perspective chosen, but in no case was the difference sufficient to change overall policy recommendations.

LIMITATIONS

Chronic musculoskeletal pain conditions where self-management is recommended, but not as a primary treatment, were excluded. Gray literature was excluded.

CONCLUSION

Substantial heterogeneity in the cost components captured in the assessment of self-management for CMP was found; this was independent of the analytic perspective used. Greater efforts to ensure complete and consistent costings are required if reliable cost-effectiveness evidence of self-management interventions is to be generated and to inform the most appropriate perspective for economic analyses in this field.

Back Injury Prevention Interventions in the Workplace

The purpose of this integrative review is to describe the state of knowledge about the effect of worksite back injury prevention programs on selected study outcomes. Fifteen experimental and quasi-experimental studies published between 1987 and 1994 were identified through a comprehensive literature search. The research studies were reviewed and analyzed using a data collection abstracting tool. Four types of back injury prevention intervention programs were identified: back belts, back schools, exercise/flexibility training, and educational classes. Positive program outcomes were reported for all four program types; however, the back school and the exercise/flexibility training programs were studied more frequently and demonstrated a greater proportion of positive results than the other two program types. Conclusions should be viewed cautiously due to the small number of studies reviewed and their methodological limitations. Implications for occupational health nursing practice and future research related to worksite back injury prevention are offered.

Efficacy of Office Ergonomics Education

The incidence of musculoskeletal injuries associated with computer use is increasing. Education has been advocated as a prevention method for reducing the incidence and severity of musculoskeletal injuries. Although the inclusion of education in musculoskeletal injury prevention programs has become a popular practice, the efficacy of educational programming is poorly defined in the literature. The present study was designed to investigate the efficacy of worker education programs in preventing musculoskeletal injuries in a population of reservation center employees who spend the majority of their work day using the computer. Participants were randomly assigned to one of three study groups (control, traditional education, or interactive education). Data collection utilized self-report surveys and observational checklists to collect data prior to intervention and at approximately 3, 6, and 12 months post intervention. Preliminary analysis of the data seems to indicate that, overall, education does have some impact on worker comfort, work area configuration, and worker postures.

Effectiveness of participatory training for prevention of musculoskeletal disorders: a randomized controlled trial

PURPOSE

Health and safety training program has been applied to prevent work-related musculoskeletal disorders (MSDs) in workplace. We evaluated the effectiveness of participatory training and didactic training programs on MSD prevention among frontline workers in Shenzhen, China.

METHODS

The authors randomly assigned 918 workers from intervention factories to receive participatory training (intervention group), and 907 workers from intervention factories and 1,654 workers from control factories to receive didactic training (control_1 group, control_2 group, respectively) from June 1, 2008 to November 30, 2009. Participants were asked to report experience of ache, pain or discomfort in 10 body parts at baseline and 1 year after training. Data were analyzed to compare the MSD prevalence 1 year before and 1 year after training in different groups from 2009 to 2010.

RESULTS

The follow-up rate was 61 % (2,120/3,479) at 1 year after training. In the year after training, there were no statistically significant changes in the proportion of workers who reported MSD in any body part. MSD prevalence rates in the intervention group reduced from 16.8 to 9.9 % for lower extremities (χ(2) = 13.102, p < 0.001) and from 12.9 to 8.3 % (χ(2) = 9.433, p = 0.002) for wrist and finger at 1 year after training. However, the rates did not change significantly for upper back, lower back, neck, shoulder and elbow in the intervention group and for all 10 body parts in two control groups.

CONCLUSIONS

Overall, the training programs did not seem to prevent the occurrence of MSD among frontline workers. However, participatory training might be effective to reduce MSD in the lower extremities and wrist and finger.

Effectiveness of community- and workplace-based interventions to manage musculoskeletal-related sickness absence and job loss: a systematic review

OBJECTIVE

To assess the effectiveness of interventions in community and workplace settings to reduce sickness absence and job loss in workers with musculoskeletal disorders (MSDs).

METHODS

Relevant randomized controlled trials (RCTs) and cohort studies, published since 1990, were identified by screening citations from 35 earlier systematic reviews and by searching MEDLINE and Embase until April 2010. Effects were estimated by intervention category and other features, including study quality.

RESULTS

Among 42 studies (including 34 RCTs), 27 assessed return to work (RTW), 21 duration of sickness absence and 5 job loss. Interventions included exercise therapy, behavioural change techniques, workplace adaptations and provision of additional services. Studies were typically small {median sample 107 [inter-quartile range (IQR) 77-148]} and limited in quality. Most interventions appeared beneficial: the median relative risk (RR) for RTW was 1.21 (IQR 1.00-1.60) and that for avoiding MSD-related job loss was 1.25 (IQR 1.06-1.71); the median reduction in sickness absence was 1.11 (IQR 0.32-3.20) days/month. However, effects were smaller in larger and better-quality studies, suggesting publication bias. No intervention was clearly superior, although effort-intensive interventions were less effective than simple ones. No cost-benefit analyses established statistically significant net economic benefits.

CONCLUSION

As benefits are small and of doubtful cost-effectiveness, employers' practice should be guided by their value judgements about the uncertainties. Expensive interventions should be implemented only with rigorous cost-benefit evaluation planned from the outset. Future research should focus on the cost-effectiveness of simple, low-cost interventions, and further explore impacts on job retention.

The transferability of economic evaluations:testing the model of Welte

OBJECTIVE

One of the existing methods to assess the transferability of economic evaluations is the model of Welte, which is a decision-chart method that includes general and specific knockout criteria and a transferability checklist. This study aims to test Welte's model with the help of a case study.

METHODS

In this study, foreign studies were transferred to The Netherlands and then compared with a Dutch reference study. In the case study, the cost-effectiveness of physiotherapy was compared with a multidisciplinary treatment. With the help of a systematic search, several foreign studies could be identified. Based on these foreign studies, two different predictions were produced for The Netherlands. In the “all studies prediction,” all foreign studies were used. In the “Welte's model prediction,” only the foreign studies were used, which passed the general and specific knockout criteria. Both predictions were compared with the Dutch reference case.

RESULTS

A total of 14 non-Dutch studies were identified. Seven studies did not pass the general knockout criteria and one study did not pass the specific knockout criteria. As a result, 14 studies were included in the “all studies prediction” and 6 studies in the “Welte's model prediction.” The predictions yielded different results and the “Welte's model prediction” proved better on costs than the “all studies prediction.”

DISCUSSION

The application of Welte's model does influence cost and effects estimates when transferring economic data between countries. However, more cases should be subjected to the Welte transferability model before a final conclusion can be drawn.

A review of employment conditions as social determinants of health part II: the workplace

This is the second part of an article on employment conditions as social determinants of health and health inequalities. In part I of this article, we explored structural (external) employment conditions that affect health inequalities and health gradients. In this article, we try to examine the internal aspects of employment conditions that affect the same variables. It is not our intention to "box" employment conditions in a rigid framework within an internal domain of person-hazard interaction. The objective of examining this variable is to scrutinize internal aspects of employment conditions at a comprehensive policy level in conjunction with external contextual variables. Major occupational health concerns are examined in relationship to globalization, child labor, and work in the formal and informal sectors. Interventions that can eliminate or greatly reduce these exposures as well as those that have been unsuccessful are reviewed. Innovative interventions including work organization change, cleaner production, control banding, national and international coalitions, participatory training, and participatory approaches to improving the work environment are reviewed.

Back schools for nonspecific low back pain: a systematic review within the framework of the Cochrane Collaboration Back Review Group

STUDY DESIGN

A systematic review within the Cochrane Collaboration Back Review Group.

OBJECTIVES

To assess the effectiveness of back schools for patients with nonspecific low back pain (LBP).

SUMMARY OF BACKGROUND DATA

Since the introduction of the Swedish back school in 1969, back schools have frequently been used for treating patients with LBP. However, the content of back schools has changed and appears to vary widely today.

METHODS

We searched the MEDLINE and EMBASE databases and the Cochrane Central Register of Controlled Trials to November 2004 for relevant trials reported in English, Dutch, French, or German. We also screened references from relevant reviews and included trials. Randomized controlled trials that reported on any type of back school for nonspecific LBP were included. Four reviewers, blinded to authors, institution, and journal, independently extracted the data and assessed the quality of the trials. We set the high-quality level, a priori, at a trial meeting six or more of 11 internal validity criteria. Because data were clinically and statistically too heterogeneous to perform a meta-analysis, we used a qualitative review (best evidence synthesis) to summarize the results. The evidence was classified into four levels (strong, moderate, limited, or no evidence), taking into account the methodologic quality of the studies. We also evaluated the clinical relevance of the studies.

RESULTS

Nineteen randomized controlled trials (3,584 patients) were included in this updated review. Overall, the methodologic quality was low, with only six trials considered to be high-quality. It was not possible to perform relevant subgroup analyses for LBP with radiation versus LBP without radiation. The results indicate that there is moderate evidence suggesting that back schools have better short- and intermediate-term effects on pain and functional status than other treatments for patients with recurrent and chronic LBP. There is moderate evidence suggesting that back schools for chronic LBP in an occupational setting are more effective than other treatments and placebo or waiting list controls on pain, functional status, and return to work during short- and intermediate-term follow-up. In general, the clinical relevance of the studies was rated as insufficient.

CONCLUSION

There is moderate evidence suggesting that back schools, in an occupational setting, reduce pain and improve function and return-to-work status, in the short- and intermediate-term, compared with exercises, manipulation, myofascial therapy, advice, placebo, or waiting list controls, for patients with chronic and recurrent LBP. However, future trials should improve methodologic quality and clinical relevance and evaluate the cost-effectiveness of back schools.

Back schools for non-specific low-back pain

BACKGROUND

Since the introduction of the Swedish back school in 1969, back schools have frequently been used for treating patients with low-back pain (LBP). However, the content of back schools has changed and appears to vary widely today.

OBJECTIVES

To assess the effectiveness of back schools for patients with non-specific LBP.

SEARCH STRATEGY

We searched the MEDLINE and EMBASE databases and the Cochrane Central Register of Controlled Trials to May 2003 for relevant trials reported in English, Dutch, French or German. We also screened references from relevant reviews and included trials.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that reported on any type of back school for non-specific LBP were included.

DATA COLLECTION AND ANALYSIS

Four reviewers, blinded to authors, institution and journal, independently extracted the data and assessed the quality of the trials. We set the high quality level, a priori, at a trial meeting six or more of 11 internal validity criteria. As data were clinically and statistically too heterogeneous to perform a meta-analysis, we used a qualitative review (best evidence synthesis) to summarize the results. The evidence was classified into four levels (strong, moderate, limited or no evidence), taking into account the methodological quality of the studies. We also evaluated the clinical relevance of the studies.

MAIN RESULTS

Nineteen RCTs (3584 patients) were included in this updated review. Overall, the methodological quality was low, with only six trials considered to be high quality. It was not possible to perform relevant subgroup analyses for LBP with radiation versus LBP without radiation. The results indicate that there is moderate evidence suggesting that back schools have better short and intermediate-term effects on pain and functional status than other treatments for patients with recurrent and chronic LBP. There is moderate evidence suggesting that back schools for chronic LBP in an occupational setting, are more effective than other treatments and placebo or waiting list controls on pain, functional status and return to work during short and intermediate-term follow-up. In general, the clinical relevance of the studies was rated as insufficient.

REVIEWERS' CONCLUSIONS

There is moderate evidence suggesting that back schools, in an occupational setting, reduce pain, and improve function and return-to-work status, in the short and intermediate-term, compared to exercises, manipulation, myofascial therapy, advice, placebo or waiting list controls, for patients with chronic and recurrent LBP. However, future trials should improve methodological quality and clinical relevance and evaluate the cost-effectiveness of back schools.

Back Schools in Occupational Health Care: Design of a Randomized Controlled Trial and Cost-Effectiveness Study

OBJECTIVE

To describe the design of a randomized controlled trial (RCT), including a cost-effectiveness analysis, comparing high-intensity and low-intensity back schools with usual care in occupational health care.

DESIGN

RCT and cost-effectiveness analysis.

STUDY POPULATION

Employees sick-listed for a period of 3 to 6 weeks because of nonspecific low back pain. Interventions High-intensity back school treatment consists of a training program based on the principles of cognitive-behavioral therapy. Low-intensity back school treatment is comparable to the original Swedish Back School. Usual care is provided by the occupational physician according to the Dutch guidelines for the occupational health treatment of patients with low back pain.

OUTCOME MEASURES

Primary outcome measures are return to work, pain intensity, functional status, and general improvement. Secondary outcome measures are kinesiophobia and pain coping. The cost-effectiveness analysis includes the direct and indirect costs. The outcome measures are assessed before randomization and 3, 6, and 12 months after randomization.

CONCLUSION

RCTs of different methodological quality have been conducted to examine the effectiveness of back schools in occupational health care. The large variation in type, content, and intensity of back schools has led to conflicting evidence. Therefore, 2 different forms of back schools are compared. Moreover, this is the first RCT to include a cost-effectiveness analysis comparing low-intensity and high-intensity back schools with usual care in occupational health care.

The effects of back schools--a meta-analysis

Back schools are educational programmes for the prevention and rehabilitation of back pain. A quantitative review (meta-analysis) was performed to synthesize the existing evidence on their effectiveness, for different outcome criteria and time categories. On the basis of a systematic literature research, 18 controlled back school studies with a total of 1682 participants could be included in the meta-analysis. Effect sizes that compared back school patients with patients in a control group were calculated for 14 outcome criteria and four time categories. Effectiveness of back schools was shown for the time period within 6 months of intervention. However, effects for the 14 examined criteria revealed large differences: in contrast to the strong effects on correct back posture and movements and on knowledge of back school contents, the intervention had only small effects on health economic variables (e.g. utilization of the health care system) and no effects on clinical variables (e.g. pain intensity). With regard to the time period following the 6 months after intervention, the analysed data does not strongly support the effectiveness of back schools. It is concluded that the effectiveness of back school intervention depends on the outcome criterion and time of measurement. The results suggest that the concept of back school programmes should be improved and systematically re-evaluated.

A bibliography of cost-effectiveness practices in physical medicine and rehabilitation: AAPM&R white paper

Cost-effectiveness studies attempt to determine the ratio of costs to outcomes of a particular intervention or treatment and to compare a standard intervention with an alternative intervention to determine if the alternative is more cost effective. The goal is to establish priorities for the resources allocation and to decide among alternative interventions for the same medical condition. The global process of rehabilitation does not usually lend itself to cost-effective analysis (due to the complex set of treatments provided) but rather to specific interventions and specific aspects of outcome. The American Academy of Physical Medicine and Rehabilitation has published a cost effectiveness annotated bibliography on the Internet (http://www.aapmr.org/memphys/cebfinala.htm) that identifies 132 studies in the literature that meet specified criteria and are related to the field of rehabilitation. This White Paper attempts to interpret and synthesize the studies in that bibliography that relate to stroke, spinal cord injury (SCI), orthopedic conditions, pain syndromes, amputations, and traumatic brain injury (TBI). Most studies support the cost effectiveness of care for stroke and SCI in dedicated units or centers rather than in a general medical unit. Studies also support back programs and revascularization procedures in limb ischemia. Studies in TBI underscore the significant financial resources for the care of these patients as well as the potential benefit from rehabilitation services even in the most severely injured. Further high quality research in this area is needed.

Preventive interventions for back and neck pain problems: what is the evidence?

STUDY DESIGN

A review of controlled trials.

OBJECTIVES

To determine which interventions are used to prevent back and neck pain problems as well as what the evidence is for their utility.

SUMMARY OF BACKGROUND DATA

Given the difficulty in successfully treating long-term back and neck pain problems, there has been a call for preventive interventions. Little is known, however, about the value of preventive efforts for nonpatients, e.g., in the general population or workplace.

METHODS

The literature was systematically searched to locate all investigations that were: 1) specifically designed as a preventive intervention; 2) randomized or nonrandomized controlled trials; and, 3) using subjects not seeking treatment. Outcome was evaluated on the key variables of reported pain, report of injury, dysfunction, time off work, health-care utilization, and cost. Conclusions were drawn using a grading system.

RESULTS

Twenty-seven investigations meeting the criteria were found for educational efforts, lumbar supports, exercises, ergonomics, and risk factor modification. For back schools, only one of the nine randomized trials reported a significant effect, and there was strong evidence that back schools are not effective in prevention. Because the randomized trials concerning lumbar supports were consistently negative, there is strong evidence that they are not effective in prevention. Exercises, conversely, showed stable positive results in randomized controlled trials, giving consistent evidence of relatively moderate utility in prevention. Because no properly controlled trials were found for ergonomic interventions or risk factor modification, there was not good quality evidence available to draw a conclusion.

CONCLUSIONS

The results concerning prevention for subjects not seeking medical care are sobering. Only exercises provided sufficient evidence to conclude that they are an effective preventive intervention. There is a dire lack of controlled trials examining broad-based multidimensional programs. The need for high quality outcome studies is underscored.

Back schools for non-specific low back pain

BACKGROUND

Since the introduction of the Swedish back school in 1980, the content of back schools has changed and appears to vary widely today. Back schools are frequently used in the treatment of low back pain patients.

OBJECTIVES

The objective of this systematic review was to assess the effects of back schools for patients with non-specific low back pain.

SEARCH STRATEGY

We searched the Medline and Embase databases up to December 1997 and the Cochrane Controlled Trials Register up to December 1998 if reported in English, Dutch, French or German. We also screened references given in relevant reviews and identified randomised trials.

SELECTION CRITERIA

Only randomised trials that reported on any type of back school for non-specific low back pain were included.

DATA COLLECTION AND ANALYSIS

Two reviewers blinded with respect to authors, institution and journal independently extracted the data and assessed trial quality. Our preset "high quality" level was 6 or more out of 11 internal validity criteria with positive scores. As data were statistically and clinically too heterogeneous, a qualitative review (best evidence synthesis) was performed. The evidence was classified into 4 levels (strong, moderate, limited or no evidence) taking into account the methodological quality of the studies.

MAIN RESULTS

Fifteen RCTs were included in our systematic review. Overall, the methodological quality was low. Only 3 trials were considered high quality. It was not possible to make relevant subgroup analyses for radiation versus no radiation or to have a relevant subgroup of studies reporting on acute low back pain only. The results indicate that there is moderate evidence that back schools have better short-term effects than other treatments for chronic low back pain, and that there is moderate evidence that back schools in an occupational setting are more effective compared to 'placebo' or waiting list controls.

REVIEWER'S CONCLUSIONS

Back schools may be effective for patients with recurrent and chronic low back pain in occupational settings, but little is known about the cost-effectiveness of back schools.

A summary of economic evaluations published in the field of rheumatology and related disciplines

INTRODUCTION

The relationship between the effectiveness of health care interventions and their costs is of increasing interest. The goal of the present study was to summarize the economic evaluations (EEs) published in the field of rheumatology and related disciplines, and to focus in particular on methodologic issues.

METHODS

MEDLINE was searched in order to identify all relevant EEs published between 1966 and February 1995. Titles and abstracts of 1,435 articles were retrieved and independently reviewed by 2 assessors. Overall, 63 articles were identified by either assessor as being definite or possible full EEs (defined as an analysis comparing 2 or more strategies involving the assessment of both costs and consequences), and were assessed independently.

RESULTS

Thirty-six articles were determined to be full EEs (33 cost-effectiveness and 3 cost-utility analyses). Most were published in the periods 1984-1990 (31%) and 1991-1995 (61%). Main areas covered were methods of prevention (44%), treatment (31%), and treatment-prevention (22%). Disorders most frequently studied were osteoarthritis (36%), osteoporosis (22%), and rheumatoid arthritis (14%). Direct and indirect costs were measured or estimated in 100% and 28% of the EEs, respectively. The viewpoint of the analysis was stated explicitly in 12 studies (33%). Incremental and sensitivity analyses were presented in 17 (47%) and 23 (64%), respectively. Inadequate use of economic terms was also documented.

CONCLUSION

The EE articles reviewed adhered partially to basic analytic methods. Economic evaluations in the field of rheumatology need to be improved to comply with current standards for the evaluation of health care interventions.

Randomized controlled trials in industrial low back pain relating to return to work. Part 2. Discogenic low back pain

The purpose of this review was to determine the efficacy of treatments for discogenic low back pain (LBP) by examining all randomized controlled trials (RCTs) of discogenic LBP published in the English language literature between 1975 and 1993 with "return to work" (RTW) as the end point. From more than 4,000 LBP citations, nearly 600 articles were initially reviewed; 35 studies met our selection criteria. Twenty-two studies were discussed in Part 1 (Acute Interventions) or will be discussed in Part 3 (Chronic Interventions). In this review, of 13 RCTs assessing interventions for LBP with sciatica, 9 were appropriate for their focus on, and radiologic confirmation of, discogenic LBP. The treatments assessed included chemonucleolysis, surgical discectomy, and epidural steroid injection. A 26-point system to assess the quality of methodologic rigor was used for each article. Our literature survey found a need for additional studies comparing surgery, conservative care, epidural steroids, traction, and other approaches to determine their individual effects for RTW after discogenic disease.

Randomized controlled trials in industrial low back pain relating to return to work. Part 1. Acute interventions

Employers and insurers are interested in being able to use cost-effective interventions for returning injured workers to the workplace. Unfortunately, truly objective information is lacking. The purpose of this and two subsequent review articles was to perform thorough scrutiny and methodologic comparison among all obtainable, published randomized and controlled studies on low back pain (LBP) interventions leading to return to work. The study was confined to English language articles published from 1975 through 1993. Of more than 4,000 LBP citations, more than 500 were chosen for review. Of that number, 35 articles met the selection criteria of randomization, reasonable controls, and work return comparisons. This paper focuses on the 10 articles relating to interventions for acute (less than 4 weeks) LBP, and considers bed rest, exercise, spinal manipulation, back school, and case management. A 26-point quality system was used to compare the methodologic rigor of each article. This literature survey demonstrated the meager scientific foundations on which our industrial rehabilitation programs are based.

Sensitivity analysis in economic evaluation: a review of published studies

A structured methodological review of journal articles published in 1992 was undertaken to determine whether recently published economic evaluation studies deal systematically and comprehensively with uncertainty. Ninety three journal articles were identified from a range of searches including a computerised search of the MEDLINE CD-Rom database. Articles were reviewed to determine how they had handled uncertainty in: a) data sources; b) generalisability; c) extrapolation; and d) analytic method. Articles were subsequently assessed to determine how they had represented this uncertainty in terms of the overall results of their analysis. Finally, studies were rated on the basis of their overall performance with respect to dealing systematically and comprehensively with uncertainty. Despite the numerous books and articles devoted to the appropriate methods to be employed by analysts conducting economic evaluation, 22 (24%) studies failed to consider uncertainty at all and 35 (38%) studies employed sensitivity analysis in a manner judged as inadequate. In all, 36 (39%) studies were judged to have given at least an adequate account of uncertainty with 13 (14%) of those judged to have provided a good account of uncertainty. Such disappointing results may reflect a general lack of detail in much of the methods literature concerning how sensitivity analysis should be applied and how results should be presented. Journal editors and readers of economic evaluation articles should acquaint themselves with the methods for handling uncertainty in order that they can critically evaluate the extent to which authors have allowed for uncertainties inherent in their analysis.

Back injury prevention programs: A critical review of the literature

Back schools are increasingly utilized as an injury prevention strategy employed at the worksite. Yet, evidence of the efficacy of back schools is limited and controversial. A review of the literature showed variance in methodologies and consequently, outcomes. Outcome measures used include physical capacity, functional abilities, costs, lost time, absenteeism, perception of pain, lifting performance, attitudes, and job satisfaction. In many studies, lack of randomization and control was found to be a limitation in experimental design. Studies which used the behavioral approach of measuring lifting behavior lacked followup and evidence of long-term effects. The type of education and feedback or reinforcement was an important issue not well-defined in the literature. A variety of hypothetical mechanisms were described as contributing to the outcome of back injury prevention programs. Additional controlled research is necessary to determine the specific mechanisms of change in an effort to further improve outcome in this area.