DOES MODIFIED WORK FACILITATE RETURN TO WORK
FOR TEMPORARILY OR PERMANENTLY DISABLED WORKERS?
Review of the Literature and Annotated Bibliography
Report prepared for the Industrial Medical Council of the State of California
and the California Commission on Health and Safety and Workers' Compensation
Niklas Krause, M.D., Ph.D., M.P.H.
Epidemiological Consultant for the Survey Research Center,
University of California at Berkeley,
and Project Director of Health Services Research in Occupational Safety and Health,
Public Health Institute, Berkeley, California
Lisa Dasinger, Ph.D.
Senior Research Associate, Public Health Institute, Berkeley, California
Andrew Wiegand, M.P.P.
Graduate Student Research Assistant, University of California at Berkeley
August 20, 1997
Injuries at the workplace can result in substantial financial losses to the employer, as well as considerable physical, emotional, and financial losses to the employee. As time off work due to a disabling injury increases, injury-related costs such as indemnity payments, medical and legal expenses, and employee substitution costs rise. The negative impact of prolonged work disability on employee and employer alike is compounded by an accompanying decrease in the probability of return to work. In fact, it is the minority of workers with long-term disability which accounts for the majority of workers' compensation costs.
Some employers offer modified work to facilitate early return to work for temporarily or permanently disabled workers. Although many experts in the field regard modified work as a cornerstone in the rehabilitation process, little is known about the availability, structure, effectiveness, and efficiency of modified work programs. The objective of this review is to synthesize and critically appraise the scientific evidence in these four areas.
The main finding of this study is that modified work programs are both effective and economically feasible. However, methodologically more rigorous studies are needed to determine the magnitude of cost savings and which program elements are most effective. In the following paragraphs, the methodology for the review and the main findings are outlined in more detail.
This report is a systematic review of the scientific literature on modified work published in the English language since 1975. The starting point for the review was a "key word" search of the titles, abstracts, and keyword sections of several thousand scientific journals in reference databases from the medical, psychological, and economic sciences for empirical information on modified work. This search yielded 1,543 potentially relevant citations. After reviewing the abstracts of these, 196 full journal articles were retrieved and independently reviewed by three researchers. The final result was a set of 29 publications for detailed review. This report describes the different types of modified work programs and evaluates their effectiveness and efficiency, taking the methodological quality of the studies into account.
Each of the 29 studies was rated for methodological quality by evaluating the degree to which it fulfilled each of five methodological criteria. These five criteria focused on methodological elements which are relevant to being able to make judgments about the effectiveness of modified work programs. Our ratings showed that 13 out of 29 publications satisfied at least half of the five criteria (a score of 2.5 or higher). These higher quality studies form the basis for determining the effectiveness of modified work programs.
Types of Modified Work Programs
There are considerable differences in the design of the reviewed modified work programs, which range from traditional "light duty" assignment with temporary changes in work hours or work tasks (19 studies) to ergonomic equipment modification (1 study), graded work exposure (4 studies), job coaching (2 studies), sheltered employment (1 study), and work trials (6 studies). Often several of these elements were used within one company. In most cases, modified work was part of a broader return to work program simultaneously including other interventions such as early injury reporting, medical diagnostic and treatment protocols, vocational rehabilitation, and educational programs. Most programs were designed for back-injured workers (11 studies). Others dealt with other musculoskeletal injuries (4), traumatic head injuries (3), or were not injury-specific (11). Most studies did not assess the effectiveness of modified work programs separate from other concurrent interventions, nor was the effectiveness of different provisions of modified work compared.
Availability of Modified Work Programs
To date no comprehensive epidemiological data exist on the prevalence of modified work programs, and little is known about injured employees' access to modified work. Only seven studies gave information on the proportion of injured workers who participated in a modified duty program. Participation rates (proportion of all employees, or all workers with a certain injury type) ranged from about 5% to 40% for these studies. One study showed that only 20 percent of over four thousand disability insurance beneficiaries who were eligible for a work trial program had any knowledge of it, but those who knew about the program where two times more likely to return to work. There is clearly a need for the complete and uniform reporting of participation rates as well as needs assessment for educating employees, employers, and treating physicians about the availability and potential benefits of existing modified work programs.
The main finding of this review is that modified work programs facilitate return to work for temporarily and permanently disabled workers. Nearly all studies report a substantial improvement in return to work rates for injured workers who participate in modified work programs. Specifically, studies rated high in methodological quality show a doubling of return to work rates when modified work programs were offered to injured workers. The number of lost work days per disabling injury was also reduced by a factor of two when companies implemented modified work programs. The range of the magnitude of effects is narrow for the 13 highest quality studies, with a factor of 0.7 at the lower end and a factor of 3.0 at the higher end.
Since few studies reported cost data, the efficiency of modified work programs is difficult to judge. However, the available rudimentary data show savings in direct injury related costs and suggest that modified work programs are at least feasible if not profitable. Direct costs savings range between 8 percent (taking program costs into account) and 90 percent (not taking program costs into account). To thoroughly evaluate the efficiency of modified work programs, additional studies are needed that take all direct and indirect injury and program costs into account in a comprehensive cost-benefit analysis. Furthermore, future studies should employ cost-effectiveness analyses which include the measurement of non-monetary benefits as outcomes.
Although nearly all of the 29 studies reviewed showed positive results for the effectiveness of modified work programs in returning workers to the workplace, a number of methodological shortcomings were noted. Most reviewed studies do not separately assess the effectiveness of modified work programs from other concurrent interventions, nor do they separately evaluate the effectiveness of different provisions of modified work. Future studies need to be designed to determine which type of work modification is most effective. In particular, the specific role of organizational and ergonomic modifications needs to be examined. The randomized controlled intervention study by Loisel which identified "participatory ergonomics" as the only effective intervention suggests an additional line of scientific inquiry, namely whether certain forms of employee participation are instrumental in effective modified work programs. Necessary improvements for future studies include, but are not limited to:
� standardization and quantification of modified work programs
� complete and uniform reporting of participation rates in modified work programs
� use of concurrent external control groups
� measurement and multivariate analyses of potential confounding factors
� sufficient follow-up time to assess sustained return to work over longer periods
� simultaneous assessment of multiple outcome measures including sustained return to work, wage loss, physical functioning, psychosocial functioning, and quality of life
� comparisons of different types of modified work or different program elements for different industries and injury types in order to determine which type of work modification is most effective
� comprehensive cost-benefit and cost-effectiveness analyses
� needs assessment for educating employees, employers, and treating physicians about the availability and potential benefits of modified work programs
The main finding of this review is that modified work programs facilitate return to work for temporarily and permanently disabled workers. Injured workers who are offered modified work programs return to work about twice as often as those who are not offered such programs. The available evidence also suggests that modified work programs are cost effective. Although few studies have adequately investigated the cost-benefit ratio of modified work programs, the magnitude of savings suggested by those that have is promising. Future studies which take into account the methodological improvements noted above are warranted in order to provide more precise estimates of the effectiveness of modified work. Especially important are studies which carry out a comprehensive cost-effectiveness analysis and those that are designed to pinpoint which aspects of modified work programs are the most effective.
This research was initiated and funded by the Industrial Medical Council of the State of California (IMC) as part of a larger study on permanent disability jointly funded by the California Commission on Health and Safety and Workers' Compensation and IMC. The work was conducted under Subcontract #422 between RAND and the Regents of the University of California. The authors thank Christine Baker, Dr. Henry Brady, Dr. Allan MacKenzie, Frank Neuhauser, and Dr. Linda Rudolph for their helpful comments and the National Institute for Occupational Safety and Health for administrative support.
Suggestion for how to cite this report:
Krause, N., Dasinger, L., Wiegand, A., Does modified work facilitate return to work for temporarily or permanently disabled workers? Review of the literature and annotated bibliography. Report prepared for the Industrial Medical Council of the State of California and the California Commission on Health and Safety and Workers' Compensation, Berkeley, California, August 20, 1997, 164 pages. (Submitted for publication to Journal of Occupational Rehabilitation)
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