Heart failure among younger rheumatoid arthritis and Crohn's patients exposed to TNF-alpha antagonists

OBJECTIVES

New onset heart failure (HF) has been associated with the use of TNF-alpha antagonists etanercept and infliximab based upon spontaneous adverse event reports. HF clinical trials of these agents were stopped early due to futility or worsening of existing HF. A potential association between etanercept and infliximab and new onset HF has been studied minimally at a population level.

METHODS

Using administrative claims from a large U.S. health care organization, we identified rheumatoid arthritis (RA) and Crohn's disease (CD) patients receiving infliximab or etanercept (exposed), and comparator cohorts of RA and CD patients receiving non-biologic immunosuppressives (unexposed). We studied adults < 50 years to reduce potential confounding related to common age-related comorbidities. Based on abstracted medical records of suspected HF cases, a physician panel adjudicated cases as definite, possible or no HF.

RESULTS

Among 4018 RA and CD patients with mean duration follow-up of 18 months, 9 of 33 suspected HF cases (identified using claims data) were adjudicated as definite (n = 5) or possible (n = 4) HF. The relative risk of HF among TNF-alpha antagonist-treated RA and CD patients was 4.3 and 1.2, respectively (P = NS for both). The absolute difference in cumulative incidence of HF among infliximab or etanercept-exposed compared to unexposed patients was 3.4 and 0.3 cases per 1000 persons for RA and CD (P = NS), respectively, yielding a number needed to harm of 294 for RA and 3333 for CD.

CONCLUSION

We found only a small number of presumed HF cases (n = 9, or 0.2%) in a large population of relatively young RA and CD patients. Although there was an increased relative risk of incident, HF that was not statistically significant among those exposed to TNF-alpha antagonists compared to those unexposed, larger cohorts are needed to provide more precise risk estimates and permit adjustment for potential confounding.

Liver enzyme monitoring in patients treated with troglitazone

CONTEXT

Soon after initial marketing in March 1997, troglitazone, the first thiazolidinedione antidiabetic agent, was found to cause life-threatening acute liver failure. The drug was removed from the market in March 2000.

OBJECTIVE

To evaluate the effect of US Food and Drug Administration (FDA) risk management efforts, including repeated labeling changes and "Dear Healthcare Professional" letters, on periodic liver enzyme monitoring of patients taking troglitazone.

DESIGN, SETTING, AND PARTICIPANTS

Claims data from a large, multistate managed care organization were used to establish 4 cohorts of patients (N = 7603) with at least 90 days of health plan enrollment before first troglitazone prescription during 4 consecutive periods spanning April 1997 to September 1999 and representing 4 progressively stringent liver monitoring recommendations.

MAIN OUTCOME MEASURES

Percentage of eligible troglitazone users in each cohort with baseline, monthly (for up to 6 months of continuous use), and complete (baseline and monthly) enzyme monitoring, based on computerized records of laboratory claims.

RESULTS

Baseline testing increased from 15% before any FDA monitoring recommendations (cohort 1) to 44.6% following 4 separate FDA interventions (cohort 4; P<.001). In cohort 4, 33.4% of users had follow-up testing after 1 month of therapy, falling to 13% after 5 months of continuous use. In all cohorts, less than 5% received all recommended liver enzyme tests by the third month of continuous use.

CONCLUSIONS

The FDA risk management efforts did not achieve meaningful or sustained improvement in liver enzyme testing. Evaluation of the impact of regulatory actions is needed before such actions can be regarded as effective or sufficient.

Organizational context and taxonomy of health care databases

An understanding of the organizational context and taxonomy of health care databases is essential to appropriately use these data sources for research purposes. Characteristics of the organizational structure of the specific health care setting, including the model type, financial arrangement, and provider access, have implications for accessing and using this data effectively. Additionally, the benefit coverage environment may affect the utility of health care databases to address specific research questions. Coverage considerations that affect pharmacoepidemiologic research include eligibility, the nature of the pharmacy benefit, and regulatory aspects of the treatment under consideration.

Healthy pregnancy program in a national managed care organization: evaluation of satisfaction and health behavior outcomes

OBJECTIVE

To evaluate satisfaction with the Healthy Pregnancy Program (HPP), which was developed to educate and coordinate the care of pregnant women in a managed care setting.

STUDY DESIGN

Telephone survey.

PATIENTS AND METHODS

A random sample of program participants at 3 large health plans were contacted by telephone to evaluate their satisfaction with the program overall and with its components, including an educational booklet and telephone contact with a HPP nurse as needed. Women also were asked about changes in health behaviors (smoking, alcohol use, diet, and stress) resulting directly from participation in the HPP. Of 1155 eligible women participating in HPP who delivered a baby from April 1997 through March 1998, 684 completed the survey. The response rate was 59%.

RESULTS

Overall satisfaction with the HPP was reported by 96% of the women, and 76% reported the 2 highest ratings of satisfaction (completely or very satisfied). Reports of satisfaction were more likely for women who entered the program early in pregnancy, who read the booklet, and who had more telephone contacts. In general, at least half of the women in each behavior category reported improving their behavior, especially if they were younger, identified as high risk, or having their first child. Verbatim comments supported the high satisfaction levels.

CONCLUSIONS

The HPP is an example of a program that was developed to improve healthcare delivery in a managed care setting and, when evaluated, was found to result in highly satisfied mothers likely to improve their health behaviors.

Population-based study of rotavirus vaccination and intussusception

BACKGROUND

During the first year that the rhesus rotavirus tetravalent vaccine (RRV-TV) was licensed, the Vaccine Adverse Event Reporting System received several reports of intussusception after vaccination. To evaluate the risk of intussusception, we conducted a retrospective cohort study in ten managed care organizations.

METHODS

Cases of intussusception were identified by searching electronic databases for diagnoses of intussusception (ICD-9 Code 560.0) in infants 1 to 11 months of age and confirmed by medical chart review. Vaccination and enrollment data were obtained from administrative databases. Incidence rate ratios (RR) of intussusception were computed by dividing incidence rates in prespecified risk intervals after vaccination by the background rate of intussusception and adjusted for age by Poisson regression. Cox proportional hazard regression was used to evaluate risk by vaccine dose.

RESULTS

Of 463,277 children 56,253 had been vaccinated with a total of 91 371 doses of RRV-TV. The incidence rate of intussusception was 25/100,000 person years among unexposed infants and 340/100,000 person years 3 to 7 days postvaccination. In the interval 3 to 7 days after vaccination, the age-adjusted RR was 16.0 (95% confidence interval, 5.5 to 46.7) for all doses combined and 30.4 (95% confidence interval, 8.8 to 104.9) after the first dose. RRs for the 8- to 14- and 15- to 21-day risk intervals were >1.0, but the confidence intervals substantially overlapped 1.0. The attributable risk was one case of intussusception per 11 073 children vaccinated.

CONCLUSIONS

RRV-TV is associated with an increased risk of intussusception. The risk is greatest 3 to 7 days after the first vaccination dose.

Contraindicated use of cisapride: impact of food and drug administration regulatory action

CONTEXT

Cisapride, a gastrointestinal tract promotility agent, can cause life-threatening cardiac arrhythmias in patients susceptible either because of concurrent use of medications that interfere with cisapride metabolism or prolong the QT interval or because of the presence of other diseases that predispose to such arrhythmias. In June 1998, the US Food and Drug Administration (FDA) determined that use of cisapride was contraindicated in such patients and informed practitioners through additions to the boxed warning in the label and a "Dear Health Care Professional" letter sent by the drug's manufacturer.

OBJECTIVE

To evaluate the impact of the FDA's 1998 regulatory action regarding contraindicated use of cisapride.

DESIGN AND SETTING

Analysis of data for the 1-year periods before (July 1997-June 1998) and after (July 1998-June 1999) the regulatory action from the population-based, pharmacoepidemiology research databases of 2 managed care organizations (sites A and B) and a state Medicaid program (site C).

PARTICIPANTS

Patients with at least 180 days of prior enrollment in 1 of the 3 sites who were prescribed cisapride at least once in the period before (n = 24 840) or after (n = 22 459) regulatory action. Patients could be included in both cohorts.

MAIN OUTCOME MEASURES

Proportion of cisapride users in each period for whom cisapride use was contraindicated by the product label, based on computerized patient medical encounter records.

RESULTS

In the year prior to regulatory action, cisapride use was contraindicated for 26%, 30%, and 60% of users in study sites A, B, and C, respectively. In the year after regulatory action, use was contraindicated for 24%, 28%, and 58% of users, a reduction in contraindicated use of approximately 2 per 100 cisapride users at each site. When the analysis was restricted to new users of cisapride after regulatory action, only minor reductions in contraindicated use were found.

CONCLUSION

The FDA's 1998 regulatory action regarding cisapride use had no material effect on contraindicated cisapride use. More effective ways to communicate new information about drug safety are needed.

Tramadol and seizures: a surveillance study in a managed care population

STUDY OBJECTIVE

To investigate the occurrence of tramadol-associated seizures.

DESIGN

Retrospective cohort and case-control studies.

SETTING

UnitedHealth Group-affiliated independent practice model health plans, from different regions of the United States, contracting with large networks of physicians.

INTERVENTION

Analysis of administrative data from a large U.S. managed care population.

PATIENTS

A cohort of 9218 adult tramadol users and 37,232 concurrent nonusers.

MEASUREMENTS AND MAIN RESULTS

Fewer than 1% of users (80) had a presumed incident seizure claim after the first tramadol prescription. Risk of seizure claim was increased 2- to 6-fold among users adjusted for selected comorbidities and concomitant drugs. Risk was highest among those aged 25-54 years, those with more than four tramadol prescriptions, and those with history of alcohol abuse, stroke, or head injury. A case-control study among users was conducted to validate incident seizure outcomes from medical records. Only eight cases were confirmed, and all had cofactors associated with increased seizure risk.

CONCLUSION

In a general population, risk of seizure may be associated with long-term therapy with tramadol or the presence of cofactors, or confined to a small sensitive population subset.

Postmarketing surveillance of medications and pregnancy outcomes: clarithromycin and birth malformations

PURPOSE

This retrospective surveillance study used linked administrative claims data and medical records to determine the rate and types of birth malformations in infants born to women exposed to the antibiotic, clarithromycin (Biaxin), during the first trimester of pregnancy.

METHODS

Pharmacy and hospital claims from eight geographically diverse health plans were used to identify women who had a delivery claim within 270 days of a clarithromycin prescription over a 5-year period (1991-1995). Hospital delivery admission medical records for 143 mothers and their 149 infants were abstracted to identify birth malformations.

RESULTS

Five infants were identified with major malformations, three with minor malformations, and four with undescended testicles likely to resolve with time. The observed rate of 3.4% (95% CI, 0.5, 6.3) for major malformations was not statistically significantly different compared to an expected rate of 2.8% based on earlier national data. There was no consistency across types of major malformations.

CONCLUSIONS

These results provide no evidence that clarithromycin is a likely major teratogen in humans. Use of claims data is one way to evaluate quickly and efficiently the safety of prescription medications in humans during pregnancy, especially when both exposure and outcome are rare.

Management of multiple sclerosis across managed care and fee-for-service systems

OBJECTIVE

To measure and compare care for adults with MS across managed care and fee-for-service (FFS) health systems.

METHODS

The authors sampled adults with MS having physician visits over a 2-year period from a group model health maintenance organization (HMO) in southern California, from a midwestern independent practice association (IPA) model managed care plan, and from the FFS portion of the practices of a random sample of southern California neurologists. The authors mailed surveys to subjects in mid-1996; 930 of 1,164 (80%) of those eligible responded. The authors measured sociodemographic and clinical characteristics, management of recent changes in mobility, bladder control, and fatigue, use of a disease-modifying agent, assessment of general health symptoms and issues, and unmet information needs. The authors adjusted comparisons between systems for comorbidity, disease severity, and disease type.

RESULTS

The groups differed on most sociodemographic and clinical characteristics. There were few differences in symptom management; differences that did exist tended toward more referrals or treatment for the FFS group. Access to the disease-modifying agent available at the time of the survey did not differ across systems, although patients' perceptions of the rationale for not using the drug did vary. General health issues and symptoms were more often assessed in the FFS and IPA systems than in the HMO, but improvement was needed across all three systems of care. There were substantial unmet information needs in all groups and especially high ones in the FFS and HMO samples.

CONCLUSIONS

Strategies to improve care for people with MS should be developed and evaluated, particularly in areas like symptom assessment and meeting patient information needs. Where variations in service delivery exist, longitudinal studies are also needed to evaluate the potential impact on outcomes and to evaluate reasons for variation.

Antibiotics and Clostridium difficile diarrhea in the ambulatory care setting

OBJECTIVE

The goal of this study was to determine the prevalence of Clostridium difficile diarrhea (CDD) and the risk for CDD associated with different oral antibiotics commonly used in the ambulatory care setting.

METHODS

The prevalence of CDD was determined for enrollees in 4 UnitedHealth Group-affiliated health plans between January 1, 1992, and December 31, 1994. Cases were identified based on the presence of an inpatient or outpatient claim with a primary diagnosis of diarrhea, a pharmacy claim for a prescription drug used to treat CDD, or a physician or facility claim for the C. difficile toxin test, and were confirmed using full-text medical records. Within a retrospective cohort design, periods of risk for CDD were defined on the basis of duration of antibiotic therapy. To control for potential selection bias created by heterogeneous rates of C. difficile testing and to limit confounding due to multiple antibiotic exposures, we used a nested case-control design, restricting eligibility to subjects who underwent screening for C. difficile and who had been exposed to only 1 antibiotic risk period with a single antibiotic.

RESULTS

The global prevalence of CDD in 358,389 ambulatory care enrollees was 12 per 100,000 person-years. In the nested case-control study, after controlling for other risk factors, 2 antibiotics demonstrated an increased association with CDD: cephalexin (odds ratio [OR] = 7.5, 95% CI = 1.8 to 34.7) and cefixime (OR = 6.4, 95% CI = 1.2 to 39.0).

CONCLUSIONS

Although CDD is thought to occur primarily in hospitalized patients, it was found to be present in an ambulatory care population, but at a low frequency. In this population, it appeared to be associated with 2 cephalosporins but not with other types of antibiotics usually linked with nosocomial CDD. Because the frequency of C. difficile testing was shown to be more common with high-risk antibiotics, CDD may be underdiagnosed in the ambulatory care setting.

General neurologist and subspecialist care for multiple sclerosis: patients' perceptions

OBJECTIVE

To compare general neurologists and MS specialists on patients' clinical characteristics and MS care as perceived by patients with MS.

METHODS

We sampled all adult patients with MS having physician visits over a 2-year period from a Midwestern managed-care organization and from the fee-for-service portion of 23 randomly selected California neurologists' practices. In mid-1996, 694 subjects were mailed questionnaires; 532 (77%) responded. Sociodemographic/clinical characteristics, recent utilization of services/treatments, unmet needs, symptom care, and research participation were measured. Of 502 subjects (94%) who indicated their usual physician providing MS care was a neurologist, 217 (43%) reported having a general neurologist and 285 (57%) reported having an MS specialist. Comparisons between these two groups were adjusted for comorbidity and disease severity.

RESULTS

General neurologist and MS specialist patient groups did not differ on any sociodemographic or clinical characteristic except age (p<0.05). Although health care utilization generally was similar, higher proportions of the MS specialist group were aware of or had discussed interferon beta-1b (IFNbeta-1b) with their physician (p<0.05) and were currently taking it (p<0.05); a smaller proportion of the MS specialist group reported stopping it because of side effects (p<0.01). Overall, levels of unmet need and care for recent symptoms were similar, but the MS specialist group reported more confidence in their physician/carefulness in listening (p<0.05). Twice as many MS specialist subjects had participated in nondrug research (p<0.05); drug study participation was similar.

CONCLUSIONS

Patients' perceptions of their care were similar in most ways for those who designated their main MS provider as a general neurologist compared to an MS specialist; however, care differed in potentially important areas. Prospective, longitudinal studies are needed to measure and relate neurologists' training, experience, knowledge, and MS patient volume with both process and outcome measures of quality of MS care.

Medical records and privacy: empirical effects of legislation

OBJECTIVE

To determine the effects of state legislation requiring patient informed consent prior to medical record abstraction by external researchers for a specific study.

DATA SOURCES/STUDY SETTING

Informed consent responses obtained from November 1997 through April 1998 from members of a Minnesota-based IPA model health plan.

STUDY DESIGN

Descriptive case study of consent to gain access to medical records for a pharmaco-epidemiologic study of seizures associated with use of a pain medication that was conducted as part of the FDA's post-marketing safety surveillance program to evaluate adverse events associated with approved drugs.

DATA COLLECTION

The informed consent process approved by an institutional review board consisted of three phases: (1) a letter from the health plan's medical director requesting participation, (2) a second mailing to nonrespondents, and (3) a follow-up telephone call to nonrespondents.

PRINCIPAL FINDINGS

Of 140 Minnesota health plan members asked to participate in the medical records study, 52 percent (73) responded and 19 percent (26) returned a signed consent form authorizing access to their records for the study. For 132 study subjects enrolled in five other health plans in states where study-specific consent was not required, health care providers granted access to patient medical records for 93 percent (123) of the members.

CONCLUSION

Legislation requiring patient informed consent to gain access to medical records for a specific research study was associated with low participation and increased time to complete that observational study. Efforts to protect patient privacy may come into conflict with the ability to produce timely and valid research to safeguard and improve public health.

Use of services by diabetes patients in managed care organizations. Development of a diabetes surveillance system. CDC Diabetes in Managed Care Work Group

OBJECTIVE

To develop a diabetes surveillance system that estimates the prevalence of diabetes and characterizes service use in diverse managed care organizations (MCOs).

RESEARCH DESIGN AND METHODS

Computerized inpatient, pharmacy, outpatient, and laboratory records were used to develop an algorithm to identify diabetes patients and to develop surveillance indicators common to the three participating MCOs. Using 1993 data, the availability, specifications, and limitations of various surveillance indicators were determined.

RESULTS

An extensive set of diabetes surveillance indicators was identified from the four sources of data. Consistent data specifications across MCOs needed to consider variation in the type of data collected, a lack of documentation on level of coverage, differences in coding data, and different models of health care delivery. A total of 16,363 diabetes patients were identified. The age-adjusted prevalence of diabetes ranged from 24 to 29 per 1,000 enrollees. Approximately one-third of patients with diabetes (32-34%) were taking insulin. The majority had one or more visits to a primary care physician during the year (72-94%). Visits to specialists were less frequent. Ophthalmologists and optometrists were the most commonly used specialists: 29-60% of the patients with diabetes at the three MCOs had visited an ophthalmologist or optometrist. About one-fifth had an overnight hospital stay during the year.

CONCLUSIONS

This diabetes surveillance system is a useful tool for MCOs to track trends in prevalence of diabetes, use of health services, and delivery of preventive care to individuals with diabetes. This system may also be useful for health care planning and for assessing use changes after new developments in diabetes care or new quality management initiatives.

Health care utilization by children with chronic illnesses: a comparison of medicaid and employer-insured managed care

OBJECTIVES

This study compared utilization of health care services by children with chronic conditions who were insured by either Medicaid or an employer group in 1992 and 1993. Five chronic conditions were selected to illustrate patterns of service use: asthma, attention deficit disorder, diabetes, epilepsy, and sickle cell anemia.

METHODOLOGY

Administrative databases were used to develop estimates of health services utilization for children <18 years of age with the five selected conditions, who had been enrolled for at least 6 continuous months. All claims for a child identified with one of these five conditions were included in the analysis, including claims for diagnoses and procedures not directly related to the primary diagnosis. Estimates were derived for eight services (eg, hospital admissions, emergency department (ED), home health). Data were used from two Independent Practice Association model health plans in two states. Differences across the states were controlled by selecting one Medicaid and one employer-insured program from each of the two plans in both states. Regional variation was controlled for because both health plans were located in one geographical region. In each case, physicians were paid on a fee-for-service basis, with generally open access to specialists rather than primary care gatekeeper models of delivery: t tests were used to compare service use rates between Medicaid and employer-insured populations.

RESULTS

A total of 8668 children across all health plan groups had at least one of the selected conditions. Because Medicaid enrolled-children tended to be younger, analyses were adjusted for age. In both systems, a greater percentage of Medicaid children had these five study conditions (5%) compared with employer-insured children (3%), suggesting that the Medicaid population was sicker. Mean length of enrollment during the 2-year study was longer for children in employer-insured programs. Children with chronic conditions enrolled in Medicaid managed care generally used services at a higher rate compared with children with similar conditions enrolled in employer-insured managed care. The extent of the increased use varied by condition, by service type, and by plan. Children with any of the chronic conditions studied had from 2 to almost 5 times more ED visits if they were enrolled in Medicaid than if they were enrolled in employer-based managed care, depending on the specific condition. In one of the two plans, Medicaid-enrolled children had more outpatient services, laboratory services, and radiography services than their counterparts in employer-based managed care. The same pattern of use was found for home health services (except for children with diabetes) and for office visits (except for children with sickle cell). The results show higher use of all services by children with asthma and diabetes in Medicaid managed care compared with employer-based managed care. In contrast, the pattern is mixed for children with epilepsy and sickle cell. The sample size of children with these conditions was smaller than with the three other conditions, which may account, in part, for a varied pattern of results. The pattern of use for attention deficit hyperactivity disorder (ADHD) was generally different from the other conditions. Children with ADHD in employer-based managed care had more hospital admissions, hospital days, and office visits than their counterparts in Medicaid managed care. In contrast, Medicaid-enrolled children with ADHD had more ED visits, laboratory services, outpatient hospital visits, and radiography services. Other than ED visits, the differences in service use between Medicaid and employer-insured children with ADHD were minimal. Of note, the pattern for ADHD is the same for most services for Plans A and B (excluding home health visits). This utilization pattern may reflect service use for comorbid conditions. Part of this difference may be explained by differences in Medicaid e

Role of technology assessment in health benefits coverage for medical devices

With the profusion of new medical technology, managed care organizations are faced with the challenge of determining which medical devices and services warrant health benefits coverage. To aid in this decision-making process, managed care companies turn to technology assessment, a process that differs from the Food and Drug Administration's review of medical devices. Health plans typically use a structured approach to implementing coverage requirements in employer group benefits contracts and use technology assessment to evaluate the scientific evidence of effectiveness to support coverage decisions. Also important is the societal context for decisions regarding coverage for new technologies and the options being considered by policy makers for accountability in technology assessment by private insurers and health plans.

Prospective, multicenter study of spinal cord stimulation for relief of chronic back and extremity pain

STUDY DESIGN

This prospective, multicenter study was designed to investigate the efficacy and outcome of spinal cord stimulation using a variety of clinical and psychosocial outcome measures. Data were collected before implantation and at regular intervals after implantation. This report focuses on 70 patients who had undergone 1 year of follow-up treatment at the time of data analysis.

OBJECTIVES

To provide a more generalizable assessment of long-term spinal cord stimulation outcome by comparing a variety of pain and functional/quality-of-life measures before and after management. This report details results after 1 year of stimulation.

SUMMARY OF BACKGROUND DATA

The historically diverse methods, patient selection criteria, and outcome measures reported in the spinal cord stimulation literature have made interpretation and comparison of results difficult. Although short-term outcomes are generally consistent, long-term outcomes of spinal cord stimulation, as determined by prospective studies that assess multidimensional aspects of the pain complaint among a relatively homogeneous population, are not well established.

METHODS

Two hundred nineteen patients were entered at six centers throughout the United States. All patients underwent a trial of stimulation before implant of the permanent system. Most were psychologically screened. One hundred eighty-two patients were implanted with a permanent stimulating system. At the time of this report, complete 1-year follow-up data were available on 70 patients, 88% of whom reported pain in the back or lower extremities. Patient evaluation of pain and functional levels was completed before implantation and 3, 6, 12, and 24 months after implantation. Complications, medication usage, and work status also were monitored.

RESULTS

All pain and quality-of-life measures showed statistically significant improvement during the treatment year. These included the average pain visual analogue scale, the McGill Pain Questionnaire, the Oswestry Disability Questionnaire, the Sickness Impact Profile, and the Back Depression Inventory. Overall success of the therapy was defined as at least 50% pain relief and patient assessment of the procedure as fully or partially beneficial and worthwhile. Using this definition, spinal cord stimulation successfully managed pain in 55% of patients on whom 1-year follow-up is available. Complications requiring surgical intervention were reported by 17% (12 of 70) of patients. Medication usage and work status were not changed significantly.

CONCLUSIONS

This prospective, multicenter study confirms that spinal cord stimulation can be an effective therapy for management of chronic low back and extremity pain. Significant improvements in many aspects of the pain condition were measured, and complications were minimal.

Health services research at United HealthCare Corporation: the role of the Center for Health Care Policy and Evaluation

This article describes collaborative health services research and performance evaluation activities at United HealthCare Corporation, a national health care management services company. We outline the development of a research capacity within our company, the principal data sources used, and the types of research conducted. The importance of health services research within a managed care system is illustrated using two projects as examples. finally, we discuss issues faced by organizations such as ours in defining appropriate research priorities, ensuring health plan participation, and disseminating research findings. Lessons learned should be of interest to health services researchers working in or collaborating with managed care organizations as well as others seeking to understand the dynamics of research in private-sector health care companies.

Prognostic factors of spinal cord stimulation for chronic back and leg pain

Spinal cord stimulation (SCS) has been used for more than 20 years in the treatment of diverse pain conditions. Although recent studies have identified more clearly those conditions for which SCSoffers a favorable prognosis, the identification of a patient population in whom reasonably long-term success can be expected has been difficult. In an effort to improve patient selection and increase the overall success rate of treatment, we have examined various physical, demographic, and psychosocial variables as predictors of SCS outcome. The study population consisted of 40 patients with chronic low back and/or leg pain, 85% of whom were diagnosed with failed back surgery syndrome. Medical history and demographic data were collected as part of an initial assessment along with patient responses to the Minnesota Multiphasic Personality Inventory, the visual analogue pain rating scale (VAS), the McGill Pain Questionnaire, the Oswestry Disability Questionnaire, the Beck Depression Inventory, and the Sickness Impact Profile. Treatment outcomes were examined and found to improve significantly after 3 months of stimulation. Subsequent regression analysis revealed that patient age, the Minnesota Multiphasic Personality Inventory depression subscale D, and the evaluative subscale of the McGill Pain Questionnaire (MPQe) were important predictors of posttreatment pain status. Increased patient age and D subscale scores correlated negatively with pain status, as measured by the percentage of changes in pretreatment and posttreatment VAS scores, % delta VAS. In contrast, higher MPQe correlated with improved pain status. By the use of the following equation and the definition commonly associated with SCS success (at least 50% decrease in the VAS pain level), the success or failure of 3 months of SCS was correctly predicted in 88% of the study population. Our results suggest that patient age, Minnesota Multiphasic Personality Inventory depression, and MPQe may be clinically useful in the prediction of pain status after 3 months of SCS in patients with chronic low back and/or leg pain. % delta VAS = 112.57 - 1.98 (D)-1.68 (Age) + 35.54 (MPQe).

Epidural spinal cord stimulation in the management of spasms in spinal cord injury: a prospective study

Forty-eight spinal cord injury victims were implanted with an epidural spinal cord stimulation system to treat spasms that had not satisfactorily responded to medical therapy. All the patients were at least 6 months after the injury. The protocol included assessment by independent examiners preoperatively and at 3, 6, 12 and 24 months after the implant. Pre- and postoperative data collection included the frequency and severity of the spasms. Combining the frequency and intensity scores into a 'severity' score provided a more accurate clinical picture. No patient observed neurological deterioration following the surgical procedure or the neurostimulation treatment. A statistically significant reduction in the severity of the spasms was observed in the follow-up evaluations, with results that progressively increased in time. It is appears that spinal cord stimulation is an effective and safe alternative in the management of spasms in spinal cord injury victims. Its exact role in relation to intrathecal baclofen infusion and ablative procedures remains to be defined.

Totally implantable spinal cord stimulation for chronic pain: design and efficacy

Neurostimulators used to treat chronic, intractable pain have evolved from technical developments in pacemaker technology. A totally implantable spinal cord stimulation (SCS) system was designed based on elements of a widely used cardiac pacemaker. This paper reports on the transformation of pacemaker technology for neurostimulation applications and presents results of using this system for the treatment of 90 patients with chronic, intractable pain of the low back and/or legs. Significant reduction in pain levels resulted from use of a totally implantable spinal cord stimulation system. Seventy percent of the patients experienced good or excellent pain relief at an average of 14.5 months after implant. Patients who used an automatic ON/OFF cycling mode of stimulation reported greater pain relief than patients who were stimulated continuously.

Structural characteristics of medical group practices

This study of 247 medical group practices explores the structural characteristics of these emerging organizational forms. As size and complexity of services increase, group practices tend to increase the number of hierarchical levels of authority and become more formal and bureaucratic. Complexity of services was found to have more influence on the formation of subdivisions, while size was more influential in terms of levels of administration. Large group practices, and especially large multispecialty groups, appear to engage in a highly organized corporate style of medical practice. In these organizations, important professional decisions are shifted from the clinician to the administrator.