Case Management, Disability Prevention, and Outcomes Research

Gary M. Franklin, MD, MPH
Deborah Fulton-Kehoe, MPH

University of Washington
Occupational Epidemiology and Health Outcomes Program
Department of Environmental Health
School of Public Health and Community Medicine
1914 N. 34th Street, #101
Seattle, Washington 98103

ABSTRACT

Case management may be of benefit for catastrophic injuries, but its effectiveness in improving the outcome of non-catastrophic injuries is less clear. The type of case management, as well as its timing, are critical factors to assess in any evaluation of case management programs. In the first several months after injury, cost-effective case management depends on accurate identification of workers at risk for longer term disability. In workers already disabled for longer times (e.g., >1 year), the cost effectiveness of case management is much less certain. Understanding the natural history of disability progression among injured workers is the key to prudent purchase of effective case management services.

INTRODUCTION AND SIGNIFICANCE

The small percent of workers who develop long term disability (>6 months) following work-related injuries account for the largest proportion of productivity lost and cost in the workersí compensation system (Figure 1). In Washington State, 5% of injuries account for 85% of cost. In addition, the overwhelming majority of these injuries (88%) are non-catastrophic, including back sprains/strains, and carpal tunnel syndrome. 1 Most workers with disabling injuries (>3 days lost work time) return to work quickly, 50ñ60% within 4 weeks. But if a worker develops 3 months of time loss, there is a 50% chance he/she will be disabled at least one year. In other words, one must act early if there is any hope of disability prevention; many case management programs have such an early intervention focus.

The problem is that case management is expensive, and most vendors selling such services depend on screening the majority of injured workers who would be destined to return to work quickly without case management. Targeting case management to workers identified to be at greatest risk for long term disability would be more cost effective, but accurate screening procedures to identify those at greatest risk are not readily available. The purpose of this paper is to fully summarize data from several studies conducted in Washington State that may help illuminate the type and timing of case management services most likely to be (and not to be) of benefit to injured workers.

METHODS AND RESULTS
Early Identification of Workers at Greatest Risk for Long Term Disability

In a random sample of 28,000 compensable claims over 3 years (1987ñ1989), 1 the strongest predictors of long term disability were hospitalization, older age, and a diagnosis of carpal tunnel syndrome. Older workers with carpal tunnel syndrome were at particularly high risk (Table 1), and should be case managed from the time the injury is reported. In these cases, the focus should be on conservative measures with attempts to stay at regular or modified work. If this fails, data is strongly suggestive that surgery has clear advantages over conservative management in proven cases.

Other classes of workers at greatest risk for long term disability are not as clearly defined. While it is generally agreed that the set of factors most likely to be predictive is a combination of work, medical, administrative, psychosocial, and demographic factors, the weight of each of these factors in any given worker is unknown. A large, population-based prospective study will be necessary to validate predictive models that can be operationalized for targeting case management services.

What Types of Early Intervention Case Management Programs Work?

One could classify the types of case-management programs as in Table 2. While nursing and vocational case management are probably the most commonly purchased services, case management within occupational medicine centered networks is becoming more commonplace. While this is encountered in hospital based Business Health services, more highly integrated networks are evolving as well. The hallmark of such networks include occupational medicine oversight, a focus on both primary and disability prevention, use of treatment protocols, and use of more traditional case management in complex cases.

Our own experience with expert systems case management demonstrated that it did not reduce work loss days or medical costs. This program was implemented statewide in 1991 targeted to workers with compensable back and neck injuries. The majority of workers were contacted within two weeks of injury and proprietary algorithms were applied to determine if different treatment options should be considered. Table 3 reveals that no differences in outcomes at two years were seen for eligible workers before and after the start-up of the program.

Disability Prevention using Field-based Enhanced Claims Management

The Washington State Department of Labor and Industries was authorized to conduct pilot studies in Everett and Yakima, Washington to determine if claims management with reduced case load and enhanced with nurse and vocational case management was effective in preventing long term disability. Employers in each county were randomized to receive the enhanced claims management, or claims management as usual, when their workers became injured. While results are still very preliminary, the first year cohort (interventionóN=4,001; controlóN=3,575), demonstrated a 30% reduction in 6-month disability after a mean follow-up time of 8 months. Additional benefits included a dramatic reduction in need for private vocational services, and an 11% (workers), 30% (providers), and 50% (employers) reduction in protests. Medical costs were not reduced and may actually be increased to achieve other long term results.

CONCLUSIONS AND RECOMMENDATIONS FROM THE RESEARCH

• Disability prevention and return to work, rather than disability management, should be the strategic focus in purchasing case management services.
• Case management programs should have built-in evaluation components to determine their effectiveness.
• Targeting of case management services early on to workers at greatest risk of developing long term disability would be cost effective.
• Further prospective, population-based studies will be necessary to more clearly identify and operationalize factors likely to predict long term disability.
• It is likely that highly integrated services will be more effective than single intervention case-management services. The use of expert system-based algorithm may not be effective in all settings.
• There is not substantial evidence, at this time, that case management of already disabled workers is effective in reducing disability.
  

REFERENCES

1. Cheadle A, Franklin G, Wolfhagen C, et al. Factors influencing the duration of work-related disability: a population-based study of Washington State workersí compensation. Am J Public Health 1994; 84:190ñ196.

Table 1

Percent of Workers with at least 180 Days of Time Loss

From Neurology 1995; 45 (suppl):464

Table 2

Types of Case Management Services:

Nurse case management
Vocational case management
Occupational medicine focused networks
Enhanced claims management
Expert systems case management

Table 3

Outcomes of an Expert Systems Case Management Program in Washington State, 1991

*p-values were determined from ANOVA or Chi Square analysis.
†Outcomes were calculated for the two-year period following the injury date..

Less than 1.5% of subjects in any of the groups were excluded because of missing outcome data

FIGURE 1

Overall percentage of workers receiving disability payments
after the indicated number of months since injury

Adapted from Cheadle A et al. Factors influencing the duration of work-related disability: a population-based study of Washington State workersí compensation. Am J Public Health 1994; 84:190ñ196.