Improving the quality of workers' compensation health care delivery: the Washington State Occupational Health Services Project.

This article has summarized research and policy activities undertaken in Washington State over the past several years to identify the key problems that result in poor quality and excessive disability among injured workers, and the types of system and delivery changes that could best address these problems in order to improve the quality of occupational health care provided through the workers' compensation system. Our investigations have consistently pointed to the lack of coordination and integration of occupational health services as having major adverse effects on quality and health outcomes for workers' compensation. The Managed Care Pilot Project, a delivery system intervention, focused on making changes in how care is organized and delivered to injured workers. That project demonstrated robust improvements in disability reduction; however, worker satisfaction suffered. Our current quality improvement initiative, developed through the Occupational Health Services Project, synthesizes what was learned from the MCP and other pilot studies to make delivery system improvements. This initiative seeks to develop provider incentives and clinical management processes that will improve outcomes and reduce the burden of disability on injured workers. Fundamental to this approach are simultaneously preserving workers' right to choose their own physician and maintaining flexibility in the provision of individualized care based on clinical need and progress. The OHS project then will be a "real world" test to determine if aligning provider incentives and giving physicians the tools they need to optimize occupational health delivery can demonstrate sustainable reduction in disability and improvements in patient and employer satisfaction. Critical to the success of this initiative will be our ability to: (1) enhance the occupational health care management skills and expertise of physicians who treat injured workers by establishing community-based Centers of Occupational Health and Education; (2) design feasible methods of monitoring patient outcomes and satisfaction with the centers and with the providers working with them in order to assess their effectiveness and value; (3) establish incentives for improved outcomes and worker and employer satisfaction through formal agreements with the centers and providers; and (4) develop quality indicators for the three targeted conditions (low back sprain, carpal tunnel syndrome, and fractures) that serve as the basis for both quality improvement processes and performance-based contracting. What lessons or insights does our experience offer thus far? The primary lesson is the importance of making effective partnerships and collaborations. Our policy and research activities have benefited significantly from the positive relationship the DLI established with the practice community through the Washington State Medical and Chiropractic Associations and from the DLI's close association with the Healthcare Subcommittee of the Workers' Compensation Advisory Committee. This committee is established by state regulation and serves as a forum for dialogue between the committee and the employer and labor communities. Our experience thus underscores the importance of establishing broad-based support for delivery system innovations. Our research activities have also benefited from the close collaboration between DLI program staff and UW health services researchers. The DLI staff brought important program and policy experience, along with an appreciation of the context and environment within which the research, policy, and R&D activities were conducted. The UW research team brought scientific rigor and methodological expertise to the design and implementation of the research and policy activities. In Washington State, the DLI represents a "single payer" for the purposes of workers' compensation. As discussed earlier, Washington State, along with five other states, has a state-fund system that requires all employers that are not self-insured to purchase workers' compensation insurance through the state fund. No matter what one feels about the merits or drawbacks of a single-payer system of health care financing, the fact is that such a system creates important opportunities for policy initiatives and for research and evaluation. Our ability to access population-based data on injured workers and to develop policy initiatives through innovation and pilot testing to assess whether proposed changes are really improvements has been critical. Understanding what works within the constraints and complexities of the system on a small scale is critical in order to bring forth policy and processes that will be of value systemwide. Finally, we note that general medical care faces many of the same quality-related problems and challenges as occupational health care. Medical care for chronic diseases, such as diabetes, is often fragmented and uncoordinated. (ABSTRACT TRUNCATED)

Evaluation of the Washington State Workers' Compensation Managed Care Pilot Project I: medical outcomes and patient satisfaction.

OBJECTIVES: This study examined the effect of managed care on medical outcomes and patient satisfaction as part of an evaluation of the Washington State Workers' Compensation Managed Care Pilot. METHODS: One hundred twenty firms (7,041 employees) agreed to have their injured workers treated in managed-care plans. Managed care introduced two changes from the fee-for-service (FFS) delivery system currently used by injured workers in Washington State: (1) experience-rated capitation, and (2) a primary occupational-medicine delivery model. The FFS control group included injured workers employed at 392 firms (12,000 employees). A total of 1,313 workers who experienced occupationally related injuries or illnesses between April 1995 and June 1996 were interviewed by telephone at 6 weeks after injury regarding their medical outcomes and satisfaction with care. Workers whose injuries resulted in four or more lost workdays (n = 372) were also interviewed at 6 months after injury on the same topics. The areas surveyed included functional outcomes and satisfaction with care, providers, and access to providers. RESULTS: The measures of functional outcome reflected no consistent differences between the managed care and the FFS conditions. The workers who attended the managed-care system reported lower levels of satisfaction with care, particularly with access to providers. For example, 58% of managed-care patients reported satisfaction with their attending physician as compared with 69% of FFS patients (P<0.01). CONCLUSIONS: Workers treated through managed-care arrangements were less satisfied with their care, but their medical outcomes were similar to those of workers who received traditional FFS care. The current workers' compensation system in Washington State affords injured workers great latitude in choosing providers. If provider choice is substantially restricted by managed care, worker satisfaction is likely to diminish.

Evaluation of the Washington State Workers' Compensation Managed Care Pilot Project II: medical and disability costs.

OBJECTIVES: This study examined the effect of managed care on medical and disability costs as part of an evaluation of the Washington State Workers' Compensation Managed Care Pilot (MCP). METHODS: One hundred twenty firms (7,041 employees) agreed to have their injured workers treated in managed care plans. Managed care introduced two changes from the fee-for-service (FFS) delivery system currently used by injured workers in Washington State: experience- rated capitation and a primary occupational medicine delivery network. The FFS control group included injured workers employed at 392 firms (12,000 employees). Medical and disability costs were compared for 1,058 injuries in the managed care group and 1,159 injuries in the FFS group occurring between April 1995 and June 1996. Univariate and multivariate statistical methods were used to analyze the effects of managed care on medical and disability costs. RESULTS: The mean unadjusted medical cost per injury ($587) for the managed care group was 21.5% lower (P = 0.06) than for the FFS group ($748). Adjustment for differences in worker and firm-level characteristics through multivariate analysis had little effect on the unadjusted results, except that the difference in costs between managed care and FFS groups became statistically significant (P<0.01). The major cost differences were for outpatient surgery (cost per surgery) and ancillary services (pharmacy, x-ray, physical therapy, and all other costs). In addition, disability costs, particularly percent on time loss and time-loss cost per injury, were significantly lower (P<0.01) in the managed care group. CONCLUSIONS: The results from the MCP suggest that substantial savings in workers' compensation medical and disability costs may be realized using the type of managed care intervention designed for this study. Delivering occupational health services through managed care arrangements whose design is based on an integrated, occupational health-centered delivery model may offer a viable approach for improving delivery systems, reducing costs and encouraging greater attention to disability prevention.

AMP deaminase as a cell-age marker in transient erythroblastopenia of childhood and its role in the adenylate economy of erythrocytes.

Erythrocytes from 11 patients with presumptive diagnoses of transient erythroblastopenia of childhood were evaluated retrospectively (six) or prospectively (five) for a possible relationship between erythrocyte adenosine 5'-monophosphate aminohydrolase, adenylic acid deaminase (AMP deaminase) activity and intracellular concentrations of adenine nucleotides. Older red blood cell (RBC) cohorts in these patients consistently exhibited significantly decreased activities of AMP deaminase (approximately 5% to 70% of normal control mean) in association with increased concentrations (up to threefold) of adenosine triphosphate (ATP) and total adenine nucleotides. We postulate that the latter is a direct consequence of the former, since diminishing AMP deaminase activity in aging cells should reduce the drain on the adenine nucleotide pool imposed by irreversible deamination of AMP to inosine 5'-monophosphate. Consistent reductions in AMP deaminase activity indicate that this enzyme should also serve as a reliable marker of mean RBC age useful in diagnostic confirmation of transient erythroblastopenia. The observed increases in ATP and total adenine nucleotides in older RBCs require a reevaluation of the traditional view that age-related losses of these compounds mediate the ultimate demise of senescent erythrocytes. Similar alterations in the balance of degradative and salvage pathways in RBC nucleotide metabolism may also underlie certain cases of so-called "high ATP syndrome."

Inhibition of adenylate kinase by P1,P5-di(adenosine 5') pentaphosphate in assays of erythrocyte enzyme activities requiring adenine nucleotides.

P1,P5-di(adenosine 5')pentaphosphate (Ap5A) is an excellent inhibitor of human hemolysate adenylate kinase at concentrations near 2 microM and above. At ten times this concentration and in hemolysate enzyme assays under conditions described in this paper it appears not to alter reaction data in the case of hexokinase, phosphofructokinase, and phosphoglycerokinase. In the pyruvate kinase assay, very modest reductions in activity are noted, and kinetics with phosphoenolpyruvate, adenosine diphosphate (ADP), and uridine diphosphate (UDP) are unaltered.

Pyruvate kinase Greensboro. A four-generation study of a high K0.5s (phosphoenolpyruvate) variant.

The proband with lifelong hemolytic anemia has a high K0.5s phosphoenolypyruvate (PEP) erythrocyte pyruvate kinase (PK) variant substantially but incompletely normalized by the allosteric modifier fructose-1,6-diphosphate (F-1,6-P2) with conversion of sigmoidal to hyperbolic kinetics. Heterozygotes in four generations express qualitatively identical but less severely abnormal kinetics and lack overt hemolysis. Kinetic abnormalities are closely mimicked by sulfhydryl modification of normal PK. Three distinct clinical and metabolic phenotypes characterize the proband and two sisters: variant PK and hemolytic anemia, variant PK without clinical manifestations or hemolysis, and complete normality. Their mother, whose red cell PK is entirely normal except for a questionably slightly low Vmax, is postulated to express the gene products of nonidentical alleles, one encoding a product with mildly less favorable catalytic characteristics. At low PEP concentrations, the proband and heterozygotes for the PK mutant express only a very small fraction of normal PK activity despite apparent inheritance of one normal allele in the latter. Evidence suggests that disproportionately lowered PK activity may be a property of a heterotetrameric PK. Illusory abnormalities in nucleotide specificity are artifacts of diminished substrate affinity characterizing the mutant PK.

Erythrocyte pyruvate kinase (PK): the variable significance of "nucleotide specificity" in the characterization of mutant variants.

The half-saturation constant (K0.5s) phosphoenolpyruvate (PEP) for red cell pyruvate kinase (PK) with co-factors UDP and GDP is less than one-half that with ADP with or without additions of the allosteric modifier, fructose-1, 6-dephosphate (F-1, 6-P2) to the assay. The Vmax is markedly greater with ADP than with UDP or GDP, but with (PEP) at 0.5 mM, activity with all co-factors is about equal and at lower concentrations greater with UDP and GDP. With high K0.5s (PEP) mutant enzymes, and at the usual test concentration (lmM) for PEP when nucleotide specificity is assessed, the abnormally low saturation of variant enzymes may result in higher activity with UDP and GDP than with ADP--the opposite of the "normal situation." The apparent aberration in nucleotide specificity may thus be illusory and secondary to the abnormal K0.5s (PEP) of the mutant. Example data are recorded. Variations in K0.5s (PEP) may also be introduced during enzyme preparation for assay, particularly when partial purification is employed.

Substrate specificity and pH sensitivity of deoxyribonucleotidase and pyrimidine nucleotidase activities in human hemolysates.

Residual 5'-nucleotidase activities in hemolysates from nine subjects with severe hereditary deficiency of pyrimidine nucleotidase (PyrNase) were compared to those in normal and reticulocyte-rich controls. Dephosphorylation rates of 12 potential ribo- and deoxyribomononucleotide substrates were measured as a function of pH. Data confirmed the existence of at least two isozymes of 5'-nucleotidase, PyrNase, and 2'-deoxy-5'-ribonucleotide phosphohydrolase (dNase) distinguishable by differences in maximal velocities, substrate preferences and restrictions, and pH optima. PyrNase was confirmed to be active principally with pyrimidine substrates (UMP = dCMP greater than CMP much greater than dTMP greater than dUMP) at a pH optimum of 7.5 +/- 0.1. dNase activity occurred with both purine and pyrimidine substrates and was maximal with deoxy analogs (dIMP much greater than dUMP greater than dGMP greater than dTMP = dAMP much greater than dCMP) at a pH optimum of 6.2, but slight cross-reactivity occurred with some nondeoxy substrates (IMP greater than GMP greater than UMP = XMP greater than CMP). PyrNase and dNase may be complementary systems that serve physiologically to clear the cytosol of RNA and DNA degradation products during maturation of erythroid elements by conversion of nucleotide monophosphates to diffusible nucleosides.

Modification of erythrocyte enzyme activities by persulfides and methanethiol: possible regulatory role.

Sulfhydryl modification of 22 human erythrocyte enzymes was achieved by exposing intact erythrocytes, hemolysates, and partially purified enzymes to persulfides (RSSH) generated nonenzymatically from cystine in the presence of pyridoxal phosphate and mercaptopyruvate, which donates its sulfur to suitable acceptors with the mediation of the carrier enzyme, mercaptopyruvate sulfurtransferase (EC 2.8.1.2). The inhibition pattern was qualitatively similar for persulfides and that previously reported by us for the methylthio-group donor, methyl methanethiosulfonate. Thirteen activities were inhibited, and 9 were minimally or not at all affected. Pyruvate kinase was similarly modified by all systems in terms of phosphoenolpyruvate kinetics, thermostability, and interaction with the negative effector ATP. Partial-to-complete reversal of inhibition was documented in a subset of activities inhibited by mercaptopyruvate upon 30-min incubation with 1 mM dithiothreitol. A possible physiologic role for methylthio groups and for persulfides is discussed.

Acute intravascular hemolysis in the black rhinoceros: erythrocyte enzymes and metabolic intermediates.

Enzymes of aerobic and anaerobic glycolysis, glutathione cycling, and nucleotide metabolism were assayed on erythrocytes from 7 healthy rhinoceroses, 2 rhinoceroses during periods of intravascular hemolysis, and 1 rhinoceros without clinical signs of illness, which was the mother of 3 offspring with intravascular hemolytic syndrome. Measurements also were made of erythrocyte concentrations of glycolytic intermediates, adenine nucleotides, and glutathione. Although comparison of results for healthy and affected rhinoceroses did not identify an enzyme abnormality as a cause for the hemolytic syndrome, the data provided information regarding the metabolic characteristics of erythrocytes from healthy rhinoceroses.

Mechanisms of adenosine 5'-monophosphate catabolism in human erythrocytes.

Uncertainties regarding the role of pyrimidine nucleotidase (PyrNase) in AMP catabolism were resolved by studies of erythrocytes from normal controls, controls with young mean cell ages, and patients with hereditary hemolytic anemia due to severe deficiency of PyrNase. Hemolysates from the latter exhibited undiminished capacity to dephosphorylate AMP over a broad range of pH, indicating that PyrNase was not directly involved. In each subject group, the rates of AMP dephosphorylation between pH 5.1 and 8.3 were indistinguishable from those of IMP, suggesting a potential role for AMP-deaminase, an erythrocyte enzyme that was stimulated by coformycin at pH 7.2. Quantitative analysis of catabolites in incubated hemolysates confirmed that AMP degradation preferentially occurred via deamination to IMP with subsequent dephosphorylation by another erythrocyte nucleotidase isozyme, deoxyribonucleotidase. Both AMP-deaminase and deoxyribonucleotidase have acidic pH optima with minimal activities at physiologic pH, suggesting that this pathway of AMP catabolism could accelerate depletion of the adenine nucleotide pool and thereby mediate the demise of senescent erythrocytes sequestered in the spleen.

Adenine ribo- and deoxyribonucleotide metabolism in human erythrocytes, B- and T-lymphocyte cell lines, and monocyte-macrophages.

Ordinarily packaged in DNA, adenine deoxyribonucleotides are preferentially concentrated in erythrocyte and lymphocyte cytosol in adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) deficiency. A spectrum of cytosol enzyme activities are defined in terms of reaction velocities, K0.5s, and nucleotide partition after incubation with ribo- and deoxyribonucleotides. AMP and dAMP were dephosphorylated, but only AMP was deaminated in vitro. Although nucleotidase activity is much stronger in lymphocytes, AMP deaminase was the dominant degradative reaction in all erythrocyte and lymphocyte lysates under the conditions specified. For most cytosolic enzymes, ribonucleotides were preferred cofactors, implying that dADP and dATP often may be bystanders at metabolic events. The adenylate kinase-mediated partition of approximately equimolar ribo- and deoxyribonucleotide substrates yielded a very large preponderance of AMP in the monophosphate compartment, the monophosphates alone being directly vulnerable to degradative loss. The adenylate kinase(s) of lymphocytes differed strikingly from those of erythrocytes in reaction velocities with nucleotide cofactors, K0.5s, and in susceptibility to substrate inhibition.

Identification of thymidine nucleotidase and deoxyribonucleotidase activities among normal isozymes of 5'-nucleotidase in human erythrocytes.

The persistence of normal thymidine nucleotidase (ThyNase) activity in subjects with pyrimidine nucleotidase (PyrNase) deficiency suggested the possible existence of separate isozymes in normal human erythrocytes. This hypothesis was confirmed by studies of PyrNase-deficient individuals from five unrelated families. Erythrocytes deficient in PyrNase retained normal activity of an enzyme system preferentially active at pH 6.2 with a variety of 2'-deoxyribonucleoside 5'-monophosphate substrates, including those of uridine, thymidine, and cytidine. Lesser activities were observed with the corresponding ribonucleotides. Normal control hemolysates were also found capable of effectively dephosphorylating purine nucleotides (dAMP greater than AMP) when pH was lowered sufficiently from the pH 7.4-8.0 region commonly used in conventional assays. Variations in substrate specificity, pH optima, kinetics, and sensitivity to inactivation by Pb2+ indicated the existence of multiple 5'-nucleotidase isozymes in normal erythrocytes: PyrNase and deoxyribonucleotidase(s) that might function physiologically in the conversion of DNA-derived nucleotides to diffusible nucleosides. Evolution of such a unique 5'-nucleotidase suggests that normal erythroblast maturation and nuclear extrusion is accompanied by a degree of karyolysis sufficient to require dephosphorylation and clearance of DNA degradation products.

Pyrimidine nucleotidase deficiency with active dephosphorylation of dTMP: evidence for existence of thymidine nucleotidase in human erythrocytes.

Erythrocytes from a patient with classical pyrimidine nucleotidase (PyN) deficiency had less than 10% residual PyN activity with uridine 5'-monophosphate (UMP) or cytidine 5'-monophosphate (CMP) as substrate, but exhibited brisk nucleotidase activity with thymidine 5'-monophosphate (dTMP). This strongly suggests the existence of separate enzymes or isozymes of PyN in normal human erythrocytes--an hypothesis that should be tested by similar studies in other cases of severe PyN deficiency, whether induced by genetic defects or lead toxicity.

Pyruvate kinase isozyme (PK-Greenville) with defective allosteric activation by fructose-1,6-diphosphate: the role of F-1,6-P modulation in normal erythrocyte metabolism.

A child with chronic hemolytic anemia since birth was found to have erythrocyte pyruvate kinase (PK) in a highly unusual form relative to other mutant isozymes when characterized by International Committee for Standardization in Hematology criteria. Most properties of the partially purified isozyme (designated PK-Greenville) were altered minimally, if at all, except for nearly total insensitivity to allosteric activation by fructose-1,6-diphosphate (F-1,6-P). One parent appeared to be heterozygous for a null gene and the other for an allele governing production of the mutant isozyme. Apparent restriction of the molecular defect to ineffective activation kinetics suggests that the F-1,6-P binding site on erythrocyte PK is functionally as well as physically allosteric. The magnitude of the metabolic block at the PK step and the clinical severity indicate that allosteric modulation by F-1,6-P is a crucial property of PK in normal erythrocyte metabolism.