- Email: [email protected]
Assessing the Effectiveness of Postacute Care Rehabilitation
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Assessing the Effectiveness of Postacute Care Rehabilitation Robert L. Kane, MD ABSTRACT. Kane RL. Assessing the effectiveness of postacute care rehabilitation. Arch Phys Med Rehabil 2007;88: 1500-4. This commentary reviews a number of issues related to determining the effectiveness of postacute care including what it is (in terms of type and site of care), how to tease out the critical elements (what components of this multifaceted process are essential), the role of research designs (given the logistic difficulties of doing randomized trials, how can nonexperimental designs be used to the greatest advantage), how to assess the relation between treatment and outcomes, measurement issues (what, when, how), correcting for case mix, and potential payment schemes. Key Words: Insurance, health; Outcomes research; Rehabilitation; Reimbursement, incentives; Research design. © 2007 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation SSESSING THE EFFECTS of rehabilitation requires separating the added benefit of that enterprise from what prior A treatment (eg, joint replacement) has accomplished (eg, improved walking and pain). Because rehabilitation occurs during recuperation, this distinction is not easily made. Two separate questions can be posed: (1) Does rehabilitation help? and (2) Does the specific nature of the rehabilitation enterprise make a difference in the patient’s clinical trajectory? Moreover, the ultimate outcomes are heavily influenced by other factors, such as socioeconomic status and informal care. Put another way, rehabilitation accounts for only a modest proportion of the variance around a given outcome. Thus, assessing the effectiveness of rehabilitation requires specific efforts to partition the effects of rehabilitation separate from the other factors that can influence outcomes. Comparing alternative rehabilitative modes or techniques essentially involves efforts to explain variation within the context of factors that include patient characteristics and environmental supports.1 Such a practice tends to direct attention to short-term effects, such as the change from admission to a rehabilitation unit to discharge, whereas the socially important question is how does rehabilitation change the patient’s clinical trajectory over the long haul. The policy discussion is confused by terminology. Postacute care (PAC) overlaps with rehabilitation, but not all PAC is rehabilitative. PAC is essentially an extension of hospital care. PAC implies treatment after a hospital stay to further the goals of acute care. The major PAC venues include formal rehabilitation (usually inpatient but increasingly outpatient), skilled
From the University of Minnesota School of Public Health, Minneapolis, MN. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated. Correspondence to Robert L. Kane, MD, University of Minnesota School of Public Health, D351 Mayo (MMC 197), 420 Delaware St SE, Minneapolis, MN 55455, e-mail: [email protected]. 0003-9993/07/8811-00091$32.00/0 doi:10.1016/j.apmr.2007.06.015
Arch Phys Med Rehabil Vol 88, November 2007
nursing facility (SNF) care, and home health care. The latter 2 genres may include specific services delivered by rehabilitation professionals. PAC is a combination of recovery, recuperation, and rehabilitation. Separating these elements can be difficult. Clinical databases do not yet predict trajectories very accurately nor do they offer enough information and risk factors that affect these courses. Hence, using extant clinical information to estimate the contribution of treatment can be difficult. This commentary analyzes many elements of extant and needed research to establish more effective and efficient ways to deliver rehabilitative PAC. COMPARED WITH WHAT? The focus here is on rehabilitation’s comparative advantage in the gamut of PAC. The first question should be the following: for what problems is rehabilitation a vital factor? In truth, the question becomes especially salient because other approaches to caring for many of the problems treated by inpatient rehabilitation are available and may be equally effective. Ultimately, the first question may become, “What is rehabilitation?” We must move beyond defining a service by where or how it is provided to understanding its essential components and determining how they might be most efficiently packaged. As is typical in studies of effectiveness, more attention is spent on measures of outcomes than on measures of input. An important component of research on the effectiveness of rehabilitation will be more attention to the effects of specific elements of care. The question of effectiveness applies both within and across modalities. There are infinite variations on the themes implied by each type of treatment. Indeed, the assignment to a class of service (eg, SNF vs inpatient rehabilitative facility [IRF]) may be the result of payment incentives and regulations (often shaped by professional biases and selfinterest). The treatments of the future will undoubtedly be hybrids that combine aspects of several approaches (eg, using physical therapy [PT] techniques more aggressively in SNFs, retraining SNF staff to reinforce rehabilitation techniques, combining outpatient rehabilitation and home care). Of all the major PAC modalities, rehabilitation is the least available. Hence, substitutions are abundant (eg, SNF for IRF). Evidence of such substitution has been available for some time.2 Studies3 performed decades earlier have suggested that rehabilitation can be cost-effective for specific conditions (eg, stroke) but not others (eg, hip fracture). PAC comparisons across settings have been hindered by the absence of a common metric.4 Each type of care has adopted (or been assigned) its own approach to measurement. The gap has been further solidified by using each measurement approach as the basis for a payment system. Although rehabilitation uses the FIM instrument, nursing homes use the Minimum Data Set (MDS) and home health uses the Outcome and Assessment Information Set (OASIS). However, efforts are now underway to seek a common set of measures. METHODOLOGIC ISSUES Framing the Issue Assessing effectiveness differs depending on whether one is addressing macro- or microissues. Macroissues concern large
POSTACUTE CARE EFFECTIVENESS, Kane
questions about whether 1 form of care yields different results for persons with defined characteristics than does another approach. This is the grist of policymaking. By contrast, microquestions focus on the influence of specific care characteristics. This forms the basis for developing clinical guidelines. These 2 levels of effectiveness research use different research designs. Macroresearch generally tolerates larger variance, looking for an impact that can transcend the variation in clients and treatment elements. At the other extreme, microresearch addresses the interaction of specific patient characteristics with specific treatment elements. Study Designs On 1 level, effectiveness is distinguished from efficacy in that the former reflects the results of care given in actual practice, whereas the latter is measured in highly controlled clinical trials in which the nature of the intervention is closely monitored and systematized and the study population treated is carefully selected. The major difference in the study designs is the mode of assignment to treatment. In the case of rehabilitation, this is usually performed at the level of setting, but it could involve testing alternative protocols within a single setting. Randomized controlled trials (RCTs) rely on some type of assignment that is not influenced by patients or clinicians, whereas quasi-experimental designs face the challenge of selection bias.5 In fact, discharge destinations for PAC users are hard to model,6 suggesting that the hospital-discharge planning process is not consistent. Hospital-discharge planners use varying criteria, perhaps fueled by expediency. Differences in PAC destinations may reflect both measurable qualities, such as severity, and unmeasured differences. All sorts of statistical and design perturbations have been created in an effort to control for this bias. Clinical researchers tend to use corrections like propensity scores,7,8 whereas economists prefer to use instrumental variables that attempt to control for unmeasured differences.9 Propensity scores can adjust for only those variables that can be measured. In effect, they model the likelihood of using a given service based on the factors associated with such use and then attempt to compare groups with equal likelihood of using the service. Instrumental variables are designed to capture the variance associated with variables that cannot be measured. The relative advantage is still debated; in part, it obviously depends on how well the available putative predictive variables can actually predict utilization. In many situations, instrumental variables, which are related to the probability of using a service but not to the outcome of that service, are hard to identify. The choice of method used to address selection bias can influence the conclusions reached.10 Looked at from the opposite end, RCTs test only fixed approaches, which may not be readily replicable, whereas quasi-experimental designs can test a wide variety of approaches. Although payment constraints and eligibility requirements have placed greater bounds on the range and intensity of services provided, there remains substantial variation in the way rehabilitative services are delivered. In effect, effectiveness is the equivalent of outcomes adjusted for patient characteristics. The basic outcomes equation can be written as: outcomes ⫽ f (baseline, patient clinical characteristics, demographics, treatment). It implies that a study of the outcomes of rehabilitation must isolate the effect of the treatment by accounting for the other factors that might influence the outcomes.11 These include the
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patient’s condition before the event that led to the hospitalization, a variety of demographic elements (eg, race, sex, age, socioeconomic status, caregiver, social support), and clinical factors, usually combined under the general headings of comorbidity and severity. The treatment itself may be handled as a black box or various components may be examined directly, such as the modalities of care provided, the nature of the therapists, the duration, and intensity. Another design concern with quasi-experimental designs is ascertainment bias. The outcomes in different groups may be determined by different people who have different stakes in the outcomes or who have knowledge of what treatment was given. This knowledge may influence how they rate the outcomes. Another component of ascertainment bias involves the timing of the outcome observations (discussed below). Measuring Interventions Researchers using quasi-experimental designs have emphasized assessing independent measures in an effort to ward off challenges that the treatment and control samples differ on some important unmeasured (and hence unanalyzed) variables, whereas the critical issue of treatment has been neglected. What constitutes rehabilitation? How is it different from nursing home care? Is it the staffing, the amount of therapy time, the degree of medical oversight, the philosophy, or the clinicians’ expectations? Further work is needed to understand what elements of rehabilitation are critical in the care of specific types of patients and which of these could be equally well provided in other settings. The taxonomy for treatment is underdeveloped.11 The strongest model comes from pharmacy, where one can talk about type, dosage (how much service per day, exposure per session by number of sessions), duration, time after onset to begin therapy, and modality. In the context of PAC, other considerations include the training and skill of the therapist and the context of the delivery of care. Much is made of multidisciplinary teams, but few details are about roles offered. Which disciplines? How do they function? How are they organized? Establishing Outcomes Before one can assess outcomes, we must define them. Although there is wide agreement about what constitutes the general domains to be covered, each type of PAC has its own set of measures (eg, Inpatient Rehabilitation Facility–Patient Assessment Instrument, MDS, OASIS). Outcome measures can be divided into condition specific and generic. The former reflect elements that are inherent to a given condition (eg, the Arthritis Impact Measurement Scale12,13 measure for arthritis) or are adapted from a more generic measure to apply to a given disease (eg, a teenager’s sense of restricted activity because of the need to restrict diet in diabetes). The basic generic domains include physical functioning, cognitive performance, affect, social functioning, and perhaps satisfaction with the care received. Social functioning may be the most important because it captures the issues of greatest policy concern, whether a person can live independently and engage in meaningful activity. Some people would include cost as an outcome, but most would handle the cost of providing the services separately to calculate some sort of cost-effectiveness measure. However, future costs (eg, the costs required to maintain the individual subsequently and the costs of future care) can certainly be considered an important outcome. Function is usually expressed in terms of activities of daily living (ADLs) and instrumental activities of daily living Arch Phys Med Rehabil Vol 88, November 2007
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(IADLs), but the level of specificity and detail can vary greatly. Although a well-trained physician might be content with a 4-level measure of each major construct within the ADLs and IADLs, an occupational therapist could separate a task like dressing into many more discrete elements and assess each one. Moreover, issues like quality of performance (eg, are the clothes appropriate, do they require complex closures), speed of performance, and community participation may not be addressed. Issues around assessing function include observed versus reported performance and setting. Should the task be specifically performed and observed or do we simply rely on reports of typical behavior? Performance in a standardized test situation provides more consistency, but it may be more artificial than observing the person in her natural environment. If reported, whose report counts? Patients often rate their function higher than family and staff.14-16 Moreover, certain circumstances may create incentives to over- or underestimate function, such as concerns about litigation or a general tendency to pessimistic predictions to maximize perceptions of improvement.17 In general, PAC is unlikely to improve cognitive impairment beyond what would happen in the natural history of the underlying disease, but it can make things worse iatrogenically (eg, by excessive use of sedatives). Affect, too, can be more readily adversely influenced by care than improved. Another outcome is satisfaction, which can be separated into satisfaction with the way the care was delivered and with the actual results. Some work18 suggests that patients have short memories and are more influenced by their current state than how much they have improved. Timing the Measurements of Outcomes There is even less agreement about how and when to use the measures. Because PAC involves recovery from a primary insult, it incorporates a patient’s natural clinical course. Hence, timing is important. Clinical trajectories may affect the interpretation of benefit. For example, a longer course of rehabilitation may show greater improvement than a short stay simply because the patient has had more time to recover. Hence, all comparisons need a consistent starting point. That is usually the time of discharge from the hospital, but sometimes therapy can antedate this transition. Even with short stays, PT for hip replacements often starts during hospitalization. Such early PT has been found to be a predictor of better outcomes.19 A related concern is when to measure progress. Many systems assess gains at the end of the therapy or at discharge. However, this practice has several problems. We have already noted that the duration of therapy may vary. Functional assessment must be conducted in the setting where the patient will live, preferably after he/she has had an opportunity to acclimate. This kind of follow-up requires active effort; one cannot simply rely on getting data from those who return for care. Some people in rehabilitation lament how much a patient has deteriorated once he/she moved home, apparently blaming the environment for failing to maintain the benefits they had achieved. The ultimate, and appropriate, test of PAC effectiveness is how well the patient functions after the treatment period has ended. Such a posture may lead to new definitions of care packages that include ongoing support after PAC discharge. New episode-based payment systems would encourage such efforts (see below). The definition of success can depend on the shape of the benefit curve. Some types of treatment produce an immediate benefit, but over time the results merge with those treated in other ways. The area under the curve becomes the policy Arch Phys Med Rehabil Vol 88, November 2007
Fig 1. Hypothetical pattern of 2 clinical PAC courses.
relevant issue. For example, rehabilitation from hip fracture may yield a short-term gain in function, but by 6 or 12 months the curves from inpatient rehabilitation merge with those for persons treated in less expensive settings. Figure 1 shows 2 hypothetical clinical courses for alternative PAC treatments. At the end of the observation period, patients are in approximately the same state, but the patients following the solid line had a period of better function compared with those following the dotted line. The relevant policy question then is how much is it worth to have enjoyed that transient benefit. If the persons being treated can return to work sooner, one might argue that it behooves employers to invest in the more expensive treatment but what of those who are retired or unemployed? There have been cautions against putting a value on a laboring life.20 Consumer Perspectives Different audiences may value different outcomes differently. Consumers and clinicians may place different values on elements within the same concept (eg, ADLs, IADLs).21-25 Calculations of cost-effectiveness can vary with whose values are used.26 By contrast, although they cannot ignore customer preferences, payers may rely on outcomes that affect costs such as readmissions or subsequent care use. Case Mix Case mix can be thought about at several levels. It can describe the composition of a group of patients (ie, those in a given hospital at a given time) or it can address the attributes of each patient separately. In addition to concerns about selection bias, case mix works at another level as well. The weakness of an RCT can be said to lie in its ability to generalize. Extrapolating from a highly controlled situation with active inclusion and exclusion criteria to actual practice can be hazardous. In some instances, it may be sufficient to simply adjust for diagnosis or comorbidities. In other cases, it may be necessary to block on elements of case mix, examining patients with specified characteristics (perhaps identified as high risk and low risk) separately. PAYMENT INCENTIVES Bundling Given the problems in establishing the specific benefits of rehabilitation in many conditions and the need to consider carefully case mix when such differences are sought, it would make sense to leave the decision about what type of rehabili-
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tative PAC is most effective to service providers and instead hold them accountable for costs and outcomes. Such a policy would effectively create point-of-service capitation payments, which would be based on case-mix adjustment for acuity (and other demographic risk factors). Under a point-of-service capitation system, at the time of hospital discharge, patients would be assigned to organizations that would assume responsibility for the care of enrollees for a given period (say 3mo). They would be responsible for the costs of rehospitalizations. The concept of point-of-service capitation can be extended to include cotemporaneous medical care and prior hospital care. In the latter case, the capitation (for selected diagnoses with a high probability of needing rehabilitation) would begin on admission and would cover all care from admission to followup. The difficulty with the latter is that it requires 2 probabilities: (1) the likelihood of getting any rehabilitative care and (2) the likelihood of benefiting from it, whereas capitating the payment only for PAC requires considering only the latter. Pay for Performance Another compatible approach is pay for performance. It seems logical to hold that one should pay more for better care or at least better outcomes (despite the difficulties of parceling out how much of the outcome was actually the result of the specific care given). Before tackling the implications of pay for performance, it is important to acknowledge the validity of the equal-pay principle. Equivalent payment should be given regardless of the modality for equivalent results. That rule is currently violated regularly. Some providers of care are paid at a higher rate for comparable services, and some modalities are much better rewarded. In general, IRFs are paid more than SNFs or home health agencies. Admittedly, we rarely have strong outcomes data to compare results and hence fall back on other assumptions. One fruitful area of research would be to examine the costs of episodes of care to see just what economic role various types of PAC play in determining overall costs, including rehospitalizations. Such work would provide a useful basis for bundling payments. Pay for performance comes in several forms. Some emphasize process over outcomes. For example, if a group follows a given protocol or guideline, they may be paid more. Such rewards for adhering to guidelines need to be anchored by well-validated guidelines that are based on strong empirical evidence of benefit and perhaps on criteria of cost-effectiveness. In effect, we should encourage rehabilitative activities that have been shown to yield improvements in quality-adjusted life years, hopefully those that are more cost-effective as well. Some pay-for-performance systems require providers to show that they meet certain standards, which may include achieving prescribed levels of patient satisfaction. Less often providers are paid on the basis of the outcomes they achieve. In theory, one could titrate payment by the achievement of results. Determining such performance requires careful attention to case-mix corrections. Outcomes payments can pervert incentives. In other practice spheres, clinicians who were being judged on the basis of their performance avoided the more difficult cases.27 CONCLUSIONS This commentary has addressed a number of topics that should be considered when discussing the effectiveness of rehabilitation in the context of PAC. In general, the basic elements of outcomes research can be usefully applied here.11 However, the broad availability of alternative means to provide
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much of PAC underlines the importance of looking at both effectiveness and cost-effectiveness. The ultimate solutions will likely not be simply choices among current alternatives but the creation of better hybrid forms of care that are both more effective and more affordable. Rehabilitation needs to examine its current practices to determine which elements are crucial to its effectiveness and where there are opportunities for increased efficiency. References 1. Whyte J, Hart T. It’s more than a black box; it’s a Russian doll: defining rehabilitation treatments. Am J Phys Med Rehabil 2003; 82:639-52. 2. Neu CR, Harrison S, Heilbrunn JZ. Medicare patients and postacute care: who goes where? Santa Monica: Rand Corp; Nov 1989. Report No. R-3780-MN. 3. Chen Q, Kane RL, Finch M. The cost-effectiveness of post-acute care for elderly Medicare beneficiaries. Inquiry 2000-2001;37: 359-75. 4. Medicare Payment Advisory Commission. Report to the Congress: Medicare payment policy. Washington (DC): MedPAC; Mar 1999. 5. Kane RL, Chen Q, Finch M, Blewett L, Burns R, Moskowitz M. Functional outcomes of post-hospital care for stroke and hip fracture patients under Medicare. J Am Geriatr Soc 1998;46:152533. 6. Kane RL, Finch M, Blewett L, Chen Q, Burns R, Moskowitz M. Use of post-hospital care by Medicare patients. J Am Geriatr Soc 1996;44:242-50. 7. Rosenbaum PR, Rubin DB. The central role of the propensity score in observational studies of causal effects. Biometrika 1983; 70:41-55. 8. D’Agostino RB Jr. Propensity score methods for bias reduction in the comparison of a treatment to a non-randomized control group. Stat Med 1998;17:2265-81. 9. Angrist JD, Imbens GW, Rubin DB. Identification of causal effects using instrumental variables. J Am Stat Assoc 1996;91: 444-72. 10. Stukel TA, Fisher ES, Wennberg DE, Alter DA, Gottlieb DJ, Vermeulen MJ. Analysis of observational studies in the presence of treatment selection bias: effects of invasive cardiac management on AMI survival using propensity score and instrumental variable methods. JAMA 2007;297:278-85. 11. Kane RL, editor. Understanding health care outcomes research. 2nd ed. Sudbury: Jones & Bartlett Publishers; 2005. 12. Meenan RF, Gertman PM, Mason JH, Dunaif R. The arthritis impact measurement scales: further investigations of a health status measure. Arthritis Rhem 1982;25(9):1048-53. 13. Meenan RF. The AIMS approach to health status measurement: conceptual background and measurement properties. J Rheumatol 1982;9:785-8. 14. Rubenstein L, Schairer C, Wieland GD, Kane R. Systematic biases in functional status of assessment of elderly adults: effects of different data sources. J Gerontol 1984;39:686-91. 15. Lum TY, Lin WC, Kane RL. Use of proxy respondents and accuracy of minimum data set assessments of activities of daily living. J Gerontol A Biol Sci Med Sci 2005;60:654-9. 16. Magaziner J. The use of proxy respondents in health studies of the aged. In: Wallase RB, Woolsen RF, editors. The epidemiologic study of the elderly. New York: Oxford Univ Pr; 1992. p 120-9. 17. Siegler M. Pascal’s wager and the hanging of crepe. N Engl J Med 1975;293:853-7. 18. Kane RL, Maciejewski M, Finch M. The relationship of patient satisfaction with care and clinical outcomes. Med Care 1997;35: 714-30. Arch Phys Med Rehabil Vol 88, November 2007
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19. Thompson R, Kane RL, Gromala T, et al. Complications and short-term outcomes associated with total hip arthroplasty in teaching and community hospitals. J Arthroplasty 2002;17:3240. 20. Avorn J. Benefit and cost analysis in geriatric care: turning age discrimination into health policy. N Engl J Med 1984;310:1294301. 21. Kane RL, Rockwood T, Finch M, Philp I. Consumer and professional ratings of the importance of functional status components. Health Care Financ Rev 1997;19:11-22. 22. Kane RL, Rockwood T, Philp I, Finch M. Differences in valuation of functional status components among consumers and professionals in Europe and the United States. J Clin Epidemiol 1998;51: 657-66.
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23. Rockwood TH, Church JM, Fleshman JW, et al. Patient and surgeon ranking of the severity of symptoms associated with fecal incontinence: the fecal incontinence severity index. Dis Colon Rectum 1999;42:1525-33. 24. Kane RL, Bell RM, Riegler SZ. Value preferences for nursing home outcomes. Gerontologist 1986;26:303-8. 25. Kane RL, Rockwood T, Hyer K, et al. Rating the importance of nursing home residents’ quality of life. J Am Geriatr Soc 2005; 53:2076-82. 26. Chen Q, Kane RL. Effects of using consumer and expert ratings of an activities of daily living scale on predicting functional outcomes of postacute care. J Clin Epidemiol 2001;54:334-42. 27. Werner RM, Asch DA. The unintended consequences of publicly reporting quality information. JAMA 2005;293:1239-44.
SPECIAL SECTION: SPECIAL COMMUNICATION
Assessing the Effectiveness of Postacute Care Rehabilitation Robert L. Kane, MD ABSTRACT. Kane RL. Assessing the effectiveness of postacute care rehabilitation. Arch Phys Med Rehabil 2007;88: 1500-4. This commentary reviews a number of issues related to determining the effectiveness of postacute care including what it is (in terms of type and site of care), how to tease out the critical elements (what components of this multifaceted process are essential), the role of research designs (given the logistic difficulties of doing randomized trials, how can nonexperimental designs be used to the greatest advantage), how to assess the relation between treatment and outcomes, measurement issues (what, when, how), correcting for case mix, and potential payment schemes. Key Words: Insurance, health; Outcomes research; Rehabilitation; Reimbursement, incentives; Research design. © 2007 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation SSESSING THE EFFECTS of rehabilitation requires separating the added benefit of that enterprise from what prior A treatment (eg, joint replacement) has accomplished (eg, improved walking and pain). Because rehabilitation occurs during recuperation, this distinction is not easily made. Two separate questions can be posed: (1) Does rehabilitation help? and (2) Does the specific nature of the rehabilitation enterprise make a difference in the patient’s clinical trajectory? Moreover, the ultimate outcomes are heavily influenced by other factors, such as socioeconomic status and informal care. Put another way, rehabilitation accounts for only a modest proportion of the variance around a given outcome. Thus, assessing the effectiveness of rehabilitation requires specific efforts to partition the effects of rehabilitation separate from the other factors that can influence outcomes. Comparing alternative rehabilitative modes or techniques essentially involves efforts to explain variation within the context of factors that include patient characteristics and environmental supports.1 Such a practice tends to direct attention to short-term effects, such as the change from admission to a rehabilitation unit to discharge, whereas the socially important question is how does rehabilitation change the patient’s clinical trajectory over the long haul. The policy discussion is confused by terminology. Postacute care (PAC) overlaps with rehabilitation, but not all PAC is rehabilitative. PAC is essentially an extension of hospital care. PAC implies treatment after a hospital stay to further the goals of acute care. The major PAC venues include formal rehabilitation (usually inpatient but increasingly outpatient), skilled
From the University of Minnesota School of Public Health, Minneapolis, MN. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated. Correspondence to Robert L. Kane, MD, University of Minnesota School of Public Health, D351 Mayo (MMC 197), 420 Delaware St SE, Minneapolis, MN 55455, e-mail: [email protected]. 0003-9993/07/8811-00091$32.00/0 doi:10.1016/j.apmr.2007.06.015
Arch Phys Med Rehabil Vol 88, November 2007
nursing facility (SNF) care, and home health care. The latter 2 genres may include specific services delivered by rehabilitation professionals. PAC is a combination of recovery, recuperation, and rehabilitation. Separating these elements can be difficult. Clinical databases do not yet predict trajectories very accurately nor do they offer enough information and risk factors that affect these courses. Hence, using extant clinical information to estimate the contribution of treatment can be difficult. This commentary analyzes many elements of extant and needed research to establish more effective and efficient ways to deliver rehabilitative PAC. COMPARED WITH WHAT? The focus here is on rehabilitation’s comparative advantage in the gamut of PAC. The first question should be the following: for what problems is rehabilitation a vital factor? In truth, the question becomes especially salient because other approaches to caring for many of the problems treated by inpatient rehabilitation are available and may be equally effective. Ultimately, the first question may become, “What is rehabilitation?” We must move beyond defining a service by where or how it is provided to understanding its essential components and determining how they might be most efficiently packaged. As is typical in studies of effectiveness, more attention is spent on measures of outcomes than on measures of input. An important component of research on the effectiveness of rehabilitation will be more attention to the effects of specific elements of care. The question of effectiveness applies both within and across modalities. There are infinite variations on the themes implied by each type of treatment. Indeed, the assignment to a class of service (eg, SNF vs inpatient rehabilitative facility [IRF]) may be the result of payment incentives and regulations (often shaped by professional biases and selfinterest). The treatments of the future will undoubtedly be hybrids that combine aspects of several approaches (eg, using physical therapy [PT] techniques more aggressively in SNFs, retraining SNF staff to reinforce rehabilitation techniques, combining outpatient rehabilitation and home care). Of all the major PAC modalities, rehabilitation is the least available. Hence, substitutions are abundant (eg, SNF for IRF). Evidence of such substitution has been available for some time.2 Studies3 performed decades earlier have suggested that rehabilitation can be cost-effective for specific conditions (eg, stroke) but not others (eg, hip fracture). PAC comparisons across settings have been hindered by the absence of a common metric.4 Each type of care has adopted (or been assigned) its own approach to measurement. The gap has been further solidified by using each measurement approach as the basis for a payment system. Although rehabilitation uses the FIM instrument, nursing homes use the Minimum Data Set (MDS) and home health uses the Outcome and Assessment Information Set (OASIS). However, efforts are now underway to seek a common set of measures. METHODOLOGIC ISSUES Framing the Issue Assessing effectiveness differs depending on whether one is addressing macro- or microissues. Macroissues concern large
POSTACUTE CARE EFFECTIVENESS, Kane
questions about whether 1 form of care yields different results for persons with defined characteristics than does another approach. This is the grist of policymaking. By contrast, microquestions focus on the influence of specific care characteristics. This forms the basis for developing clinical guidelines. These 2 levels of effectiveness research use different research designs. Macroresearch generally tolerates larger variance, looking for an impact that can transcend the variation in clients and treatment elements. At the other extreme, microresearch addresses the interaction of specific patient characteristics with specific treatment elements. Study Designs On 1 level, effectiveness is distinguished from efficacy in that the former reflects the results of care given in actual practice, whereas the latter is measured in highly controlled clinical trials in which the nature of the intervention is closely monitored and systematized and the study population treated is carefully selected. The major difference in the study designs is the mode of assignment to treatment. In the case of rehabilitation, this is usually performed at the level of setting, but it could involve testing alternative protocols within a single setting. Randomized controlled trials (RCTs) rely on some type of assignment that is not influenced by patients or clinicians, whereas quasi-experimental designs face the challenge of selection bias.5 In fact, discharge destinations for PAC users are hard to model,6 suggesting that the hospital-discharge planning process is not consistent. Hospital-discharge planners use varying criteria, perhaps fueled by expediency. Differences in PAC destinations may reflect both measurable qualities, such as severity, and unmeasured differences. All sorts of statistical and design perturbations have been created in an effort to control for this bias. Clinical researchers tend to use corrections like propensity scores,7,8 whereas economists prefer to use instrumental variables that attempt to control for unmeasured differences.9 Propensity scores can adjust for only those variables that can be measured. In effect, they model the likelihood of using a given service based on the factors associated with such use and then attempt to compare groups with equal likelihood of using the service. Instrumental variables are designed to capture the variance associated with variables that cannot be measured. The relative advantage is still debated; in part, it obviously depends on how well the available putative predictive variables can actually predict utilization. In many situations, instrumental variables, which are related to the probability of using a service but not to the outcome of that service, are hard to identify. The choice of method used to address selection bias can influence the conclusions reached.10 Looked at from the opposite end, RCTs test only fixed approaches, which may not be readily replicable, whereas quasi-experimental designs can test a wide variety of approaches. Although payment constraints and eligibility requirements have placed greater bounds on the range and intensity of services provided, there remains substantial variation in the way rehabilitative services are delivered. In effect, effectiveness is the equivalent of outcomes adjusted for patient characteristics. The basic outcomes equation can be written as: outcomes ⫽ f (baseline, patient clinical characteristics, demographics, treatment). It implies that a study of the outcomes of rehabilitation must isolate the effect of the treatment by accounting for the other factors that might influence the outcomes.11 These include the
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patient’s condition before the event that led to the hospitalization, a variety of demographic elements (eg, race, sex, age, socioeconomic status, caregiver, social support), and clinical factors, usually combined under the general headings of comorbidity and severity. The treatment itself may be handled as a black box or various components may be examined directly, such as the modalities of care provided, the nature of the therapists, the duration, and intensity. Another design concern with quasi-experimental designs is ascertainment bias. The outcomes in different groups may be determined by different people who have different stakes in the outcomes or who have knowledge of what treatment was given. This knowledge may influence how they rate the outcomes. Another component of ascertainment bias involves the timing of the outcome observations (discussed below). Measuring Interventions Researchers using quasi-experimental designs have emphasized assessing independent measures in an effort to ward off challenges that the treatment and control samples differ on some important unmeasured (and hence unanalyzed) variables, whereas the critical issue of treatment has been neglected. What constitutes rehabilitation? How is it different from nursing home care? Is it the staffing, the amount of therapy time, the degree of medical oversight, the philosophy, or the clinicians’ expectations? Further work is needed to understand what elements of rehabilitation are critical in the care of specific types of patients and which of these could be equally well provided in other settings. The taxonomy for treatment is underdeveloped.11 The strongest model comes from pharmacy, where one can talk about type, dosage (how much service per day, exposure per session by number of sessions), duration, time after onset to begin therapy, and modality. In the context of PAC, other considerations include the training and skill of the therapist and the context of the delivery of care. Much is made of multidisciplinary teams, but few details are about roles offered. Which disciplines? How do they function? How are they organized? Establishing Outcomes Before one can assess outcomes, we must define them. Although there is wide agreement about what constitutes the general domains to be covered, each type of PAC has its own set of measures (eg, Inpatient Rehabilitation Facility–Patient Assessment Instrument, MDS, OASIS). Outcome measures can be divided into condition specific and generic. The former reflect elements that are inherent to a given condition (eg, the Arthritis Impact Measurement Scale12,13 measure for arthritis) or are adapted from a more generic measure to apply to a given disease (eg, a teenager’s sense of restricted activity because of the need to restrict diet in diabetes). The basic generic domains include physical functioning, cognitive performance, affect, social functioning, and perhaps satisfaction with the care received. Social functioning may be the most important because it captures the issues of greatest policy concern, whether a person can live independently and engage in meaningful activity. Some people would include cost as an outcome, but most would handle the cost of providing the services separately to calculate some sort of cost-effectiveness measure. However, future costs (eg, the costs required to maintain the individual subsequently and the costs of future care) can certainly be considered an important outcome. Function is usually expressed in terms of activities of daily living (ADLs) and instrumental activities of daily living Arch Phys Med Rehabil Vol 88, November 2007
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(IADLs), but the level of specificity and detail can vary greatly. Although a well-trained physician might be content with a 4-level measure of each major construct within the ADLs and IADLs, an occupational therapist could separate a task like dressing into many more discrete elements and assess each one. Moreover, issues like quality of performance (eg, are the clothes appropriate, do they require complex closures), speed of performance, and community participation may not be addressed. Issues around assessing function include observed versus reported performance and setting. Should the task be specifically performed and observed or do we simply rely on reports of typical behavior? Performance in a standardized test situation provides more consistency, but it may be more artificial than observing the person in her natural environment. If reported, whose report counts? Patients often rate their function higher than family and staff.14-16 Moreover, certain circumstances may create incentives to over- or underestimate function, such as concerns about litigation or a general tendency to pessimistic predictions to maximize perceptions of improvement.17 In general, PAC is unlikely to improve cognitive impairment beyond what would happen in the natural history of the underlying disease, but it can make things worse iatrogenically (eg, by excessive use of sedatives). Affect, too, can be more readily adversely influenced by care than improved. Another outcome is satisfaction, which can be separated into satisfaction with the way the care was delivered and with the actual results. Some work18 suggests that patients have short memories and are more influenced by their current state than how much they have improved. Timing the Measurements of Outcomes There is even less agreement about how and when to use the measures. Because PAC involves recovery from a primary insult, it incorporates a patient’s natural clinical course. Hence, timing is important. Clinical trajectories may affect the interpretation of benefit. For example, a longer course of rehabilitation may show greater improvement than a short stay simply because the patient has had more time to recover. Hence, all comparisons need a consistent starting point. That is usually the time of discharge from the hospital, but sometimes therapy can antedate this transition. Even with short stays, PT for hip replacements often starts during hospitalization. Such early PT has been found to be a predictor of better outcomes.19 A related concern is when to measure progress. Many systems assess gains at the end of the therapy or at discharge. However, this practice has several problems. We have already noted that the duration of therapy may vary. Functional assessment must be conducted in the setting where the patient will live, preferably after he/she has had an opportunity to acclimate. This kind of follow-up requires active effort; one cannot simply rely on getting data from those who return for care. Some people in rehabilitation lament how much a patient has deteriorated once he/she moved home, apparently blaming the environment for failing to maintain the benefits they had achieved. The ultimate, and appropriate, test of PAC effectiveness is how well the patient functions after the treatment period has ended. Such a posture may lead to new definitions of care packages that include ongoing support after PAC discharge. New episode-based payment systems would encourage such efforts (see below). The definition of success can depend on the shape of the benefit curve. Some types of treatment produce an immediate benefit, but over time the results merge with those treated in other ways. The area under the curve becomes the policy Arch Phys Med Rehabil Vol 88, November 2007
Fig 1. Hypothetical pattern of 2 clinical PAC courses.
relevant issue. For example, rehabilitation from hip fracture may yield a short-term gain in function, but by 6 or 12 months the curves from inpatient rehabilitation merge with those for persons treated in less expensive settings. Figure 1 shows 2 hypothetical clinical courses for alternative PAC treatments. At the end of the observation period, patients are in approximately the same state, but the patients following the solid line had a period of better function compared with those following the dotted line. The relevant policy question then is how much is it worth to have enjoyed that transient benefit. If the persons being treated can return to work sooner, one might argue that it behooves employers to invest in the more expensive treatment but what of those who are retired or unemployed? There have been cautions against putting a value on a laboring life.20 Consumer Perspectives Different audiences may value different outcomes differently. Consumers and clinicians may place different values on elements within the same concept (eg, ADLs, IADLs).21-25 Calculations of cost-effectiveness can vary with whose values are used.26 By contrast, although they cannot ignore customer preferences, payers may rely on outcomes that affect costs such as readmissions or subsequent care use. Case Mix Case mix can be thought about at several levels. It can describe the composition of a group of patients (ie, those in a given hospital at a given time) or it can address the attributes of each patient separately. In addition to concerns about selection bias, case mix works at another level as well. The weakness of an RCT can be said to lie in its ability to generalize. Extrapolating from a highly controlled situation with active inclusion and exclusion criteria to actual practice can be hazardous. In some instances, it may be sufficient to simply adjust for diagnosis or comorbidities. In other cases, it may be necessary to block on elements of case mix, examining patients with specified characteristics (perhaps identified as high risk and low risk) separately. PAYMENT INCENTIVES Bundling Given the problems in establishing the specific benefits of rehabilitation in many conditions and the need to consider carefully case mix when such differences are sought, it would make sense to leave the decision about what type of rehabili-
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tative PAC is most effective to service providers and instead hold them accountable for costs and outcomes. Such a policy would effectively create point-of-service capitation payments, which would be based on case-mix adjustment for acuity (and other demographic risk factors). Under a point-of-service capitation system, at the time of hospital discharge, patients would be assigned to organizations that would assume responsibility for the care of enrollees for a given period (say 3mo). They would be responsible for the costs of rehospitalizations. The concept of point-of-service capitation can be extended to include cotemporaneous medical care and prior hospital care. In the latter case, the capitation (for selected diagnoses with a high probability of needing rehabilitation) would begin on admission and would cover all care from admission to followup. The difficulty with the latter is that it requires 2 probabilities: (1) the likelihood of getting any rehabilitative care and (2) the likelihood of benefiting from it, whereas capitating the payment only for PAC requires considering only the latter. Pay for Performance Another compatible approach is pay for performance. It seems logical to hold that one should pay more for better care or at least better outcomes (despite the difficulties of parceling out how much of the outcome was actually the result of the specific care given). Before tackling the implications of pay for performance, it is important to acknowledge the validity of the equal-pay principle. Equivalent payment should be given regardless of the modality for equivalent results. That rule is currently violated regularly. Some providers of care are paid at a higher rate for comparable services, and some modalities are much better rewarded. In general, IRFs are paid more than SNFs or home health agencies. Admittedly, we rarely have strong outcomes data to compare results and hence fall back on other assumptions. One fruitful area of research would be to examine the costs of episodes of care to see just what economic role various types of PAC play in determining overall costs, including rehospitalizations. Such work would provide a useful basis for bundling payments. Pay for performance comes in several forms. Some emphasize process over outcomes. For example, if a group follows a given protocol or guideline, they may be paid more. Such rewards for adhering to guidelines need to be anchored by well-validated guidelines that are based on strong empirical evidence of benefit and perhaps on criteria of cost-effectiveness. In effect, we should encourage rehabilitative activities that have been shown to yield improvements in quality-adjusted life years, hopefully those that are more cost-effective as well. Some pay-for-performance systems require providers to show that they meet certain standards, which may include achieving prescribed levels of patient satisfaction. Less often providers are paid on the basis of the outcomes they achieve. In theory, one could titrate payment by the achievement of results. Determining such performance requires careful attention to case-mix corrections. Outcomes payments can pervert incentives. In other practice spheres, clinicians who were being judged on the basis of their performance avoided the more difficult cases.27 CONCLUSIONS This commentary has addressed a number of topics that should be considered when discussing the effectiveness of rehabilitation in the context of PAC. In general, the basic elements of outcomes research can be usefully applied here.11 However, the broad availability of alternative means to provide
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much of PAC underlines the importance of looking at both effectiveness and cost-effectiveness. The ultimate solutions will likely not be simply choices among current alternatives but the creation of better hybrid forms of care that are both more effective and more affordable. Rehabilitation needs to examine its current practices to determine which elements are crucial to its effectiveness and where there are opportunities for increased efficiency. References 1. Whyte J, Hart T. It’s more than a black box; it’s a Russian doll: defining rehabilitation treatments. Am J Phys Med Rehabil 2003; 82:639-52. 2. Neu CR, Harrison S, Heilbrunn JZ. Medicare patients and postacute care: who goes where? Santa Monica: Rand Corp; Nov 1989. Report No. R-3780-MN. 3. Chen Q, Kane RL, Finch M. The cost-effectiveness of post-acute care for elderly Medicare beneficiaries. Inquiry 2000-2001;37: 359-75. 4. Medicare Payment Advisory Commission. Report to the Congress: Medicare payment policy. Washington (DC): MedPAC; Mar 1999. 5. Kane RL, Chen Q, Finch M, Blewett L, Burns R, Moskowitz M. Functional outcomes of post-hospital care for stroke and hip fracture patients under Medicare. J Am Geriatr Soc 1998;46:152533. 6. Kane RL, Finch M, Blewett L, Chen Q, Burns R, Moskowitz M. Use of post-hospital care by Medicare patients. J Am Geriatr Soc 1996;44:242-50. 7. Rosenbaum PR, Rubin DB. The central role of the propensity score in observational studies of causal effects. Biometrika 1983; 70:41-55. 8. D’Agostino RB Jr. Propensity score methods for bias reduction in the comparison of a treatment to a non-randomized control group. Stat Med 1998;17:2265-81. 9. Angrist JD, Imbens GW, Rubin DB. Identification of causal effects using instrumental variables. J Am Stat Assoc 1996;91: 444-72. 10. Stukel TA, Fisher ES, Wennberg DE, Alter DA, Gottlieb DJ, Vermeulen MJ. Analysis of observational studies in the presence of treatment selection bias: effects of invasive cardiac management on AMI survival using propensity score and instrumental variable methods. JAMA 2007;297:278-85. 11. Kane RL, editor. Understanding health care outcomes research. 2nd ed. Sudbury: Jones & Bartlett Publishers; 2005. 12. Meenan RF, Gertman PM, Mason JH, Dunaif R. The arthritis impact measurement scales: further investigations of a health status measure. Arthritis Rhem 1982;25(9):1048-53. 13. Meenan RF. The AIMS approach to health status measurement: conceptual background and measurement properties. J Rheumatol 1982;9:785-8. 14. Rubenstein L, Schairer C, Wieland GD, Kane R. Systematic biases in functional status of assessment of elderly adults: effects of different data sources. J Gerontol 1984;39:686-91. 15. Lum TY, Lin WC, Kane RL. Use of proxy respondents and accuracy of minimum data set assessments of activities of daily living. J Gerontol A Biol Sci Med Sci 2005;60:654-9. 16. Magaziner J. The use of proxy respondents in health studies of the aged. In: Wallase RB, Woolsen RF, editors. The epidemiologic study of the elderly. New York: Oxford Univ Pr; 1992. p 120-9. 17. Siegler M. Pascal’s wager and the hanging of crepe. N Engl J Med 1975;293:853-7. 18. Kane RL, Maciejewski M, Finch M. The relationship of patient satisfaction with care and clinical outcomes. Med Care 1997;35: 714-30. Arch Phys Med Rehabil Vol 88, November 2007
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19. Thompson R, Kane RL, Gromala T, et al. Complications and short-term outcomes associated with total hip arthroplasty in teaching and community hospitals. J Arthroplasty 2002;17:3240. 20. Avorn J. Benefit and cost analysis in geriatric care: turning age discrimination into health policy. N Engl J Med 1984;310:1294301. 21. Kane RL, Rockwood T, Finch M, Philp I. Consumer and professional ratings of the importance of functional status components. Health Care Financ Rev 1997;19:11-22. 22. Kane RL, Rockwood T, Philp I, Finch M. Differences in valuation of functional status components among consumers and professionals in Europe and the United States. J Clin Epidemiol 1998;51: 657-66.
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23. Rockwood TH, Church JM, Fleshman JW, et al. Patient and surgeon ranking of the severity of symptoms associated with fecal incontinence: the fecal incontinence severity index. Dis Colon Rectum 1999;42:1525-33. 24. Kane RL, Bell RM, Riegler SZ. Value preferences for nursing home outcomes. Gerontologist 1986;26:303-8. 25. Kane RL, Rockwood T, Hyer K, et al. Rating the importance of nursing home residents’ quality of life. J Am Geriatr Soc 2005; 53:2076-82. 26. Chen Q, Kane RL. Effects of using consumer and expert ratings of an activities of daily living scale on predicting functional outcomes of postacute care. J Clin Epidemiol 2001;54:334-42. 27. Werner RM, Asch DA. The unintended consequences of publicly reporting quality information. JAMA 2005;293:1239-44.