Access intervention in an integrated, prepaid group practice: effects on primary care physician productivity

OBJECTIVE

To estimate the joint effect of a multifaceted access intervention on primary care physician (PCP) productivity in a large, integrated prepaid group practice.

DATA SOURCES

Administrative records of physician characteristics, compensation and full-time equivalent (FTE) data, linked to enrollee utilization and cost information.

STUDY DESIGN

Dependent measures per quarter per FTE were office visits, work relative value units (WRVUs), WRVUs per visit, panel size, and total cost per member per quarter (PMPQ), for PCPs employed >0.25 FTE. General estimating equation regression models were included provider and enrollee characteristics.

PRINCIPAL FINDINGS

Panel size and RVUs per visit rose, while visits per FTE and PMPQ cost declined significantly between baseline and full implementation. Panel size rose and visits per FTE declined from baseline through rollout and full implementation. RVUs per visit and RVUs per FTE first declined, and then increased, for a significant net increase of RVUs per visit and an insignificant rise in RVUs per FTE between baseline and full implementation. PMPQ cost rose between baseline and rollout and then declined, for a significant overall decline between baseline and full implementation.

CONCLUSIONS

This organization-wide access intervention was associated with improvements in several dimensions in PCP productivity and gains in clinical efficiency.

Prepaid group using prevention focus to lure back employers

Prepaid medical groups like Grand Valley Health Plan, Grand Rapids, MI, are facing declining membership as employers shift to lower-priced PPOs. But some employers are starting to look more closely again at the value of managed care networks.

Managing care: utilization review in action at two capitated medical groups

Despite widespread concern about denials of coverage by managed care organizations, little empirical information exists on the profile and outcomes of utilization review decisions. This study examines the outcomes of nearly a half-million coverage requests in two large medical groups that contract with health plans to deliver care and conduct utilization review. We found much higher denial rates than those previously reported. Denials were particularly common for emergency care and durable medical equipment. Retrospective requests were nearly four times more likely than prospective requests were to be denied, and when prospective requests were denied, it was more likely because the service fell outside the scope of covered benefits than because it was not medically necessary.

Managed care arrangements of health networks and systems. A review of the 1999 experience

The 1990s witnessed various health provider efforts to integrate health care delivery with financing functions. Physician and hospital-led organizations developed their own insurance products and also contracted on a capitated or shared-risk basis with health maintenance organizations (HMOs). Several studies exist on the efforts of physician-led health organizations in these areas, but few studies exist on hospital-led organizations. We examined unique data on hospital-led health networks and systems for 1999 and found that about 60% had provider-owned insurance products and 50% held capitated contracts for their affiliates. In addition, these hospital-led organizations--especially health systems--had comparable levels of capitated contracting when compared to physician-led organizations. Although interest in capitation has waned, current economic realities may reignite interest in these arrangements given their potential for containing health expenditures without increasing consumer risk. In light of this, it is now a good time for physicians and medical group managers to reflect on their experiences in the 1990s and to assess the merits and shortcomings of different intermediary organizations with which they may align.

Insurance product design and its effects: trade-offs along the managed care continuum

This paper uses 1996-97 Community Tracking Study data to analyze the effects of different insurance product designs on service use, access, and consumer assessments of care for nonelderly people with employer-sponsored insurance. Product types are defined by features including use of networks, gatekeeping, capitation, and group/staff model delivery systems. We found no evidence of differences across product types in unmet need or delayed care or use of hospitals, surgery, or emergency rooms. At the same time, different product designs present purchasers with a clear trade-off between paying more out of pocket and encountering more administrative barriers to care. In addition, an increasing proportion of consumers report dissatisfaction with choice of physicians and low trust in physicians as one moves along the managed care continuum from unmanaged to heavily managed products. Our findings have implications for efforts to regulate managed care. The existence of a trade-off between out-of-pocket costs and administrative barriers to care means that some forms of regulation run the risk of reducing choices available to consumers. This is particularly true of regulations that would change the nature of managed care products by prohibiting the use of specific care management tools. To the extent that the backlash against managed care targets restrictions on choice and administrative hassles among consumers who nonetheless choose more heavily managed products because of their lower cost, eliminating heavily managed products would leave those consumers worse off.

Shrinkage in risk contracting 'less than expected,' survey finds

Findings from the Fifth Annual Managed Care Indicator by Evergreen Re, a national health care consulting and reinsurance brokerage company, confirm other signs that the presence of capitation is waning slightly in the health care marketplace. Nevertheless, the number of multispecialty groups involved in capitation is still surprisingly high.

Physician incentives and the timing of cesarean sections: evidence from California

OBJECTIVES

The timing of cesarean sections is studied to examine how physician convenience and financial incentives play a role in the decision to perform a cesarean section.

METHODS

Using birth certificate and hospital financial data from California, the likelihood of cesarean sections being performed at particular times of day was examined, controlling for maternal characteristics and the mother's insurance coverage. Two diagnoses associated with cesarean sections are examined separately: fetal distress and prolonged/dysfunctional labor. The hypotheses are that cesarean sections performed for physician convenience are more likely to occur in the evening hours and that type of insurance will affect the incentive to perform cesarean sections to obtain leisure.

RESULTS

The probability of cesarean sections for patients insured by a group-model HMO is more stable during the course of a day than that for patients insured by all other insurance plans. Group-model HMO patients with previous cesarean sections are less likely to have cesarean sections in the evening hours and are less likely to be diagnosed with fetal distress or prolonged/dysfunctional labor.

CONCLUSIONS

The differences in cesarean sections and diagnosis rates between group-model HMO patients and other patients could arise from several mechanisms: group-model HMOs provide consistent financial incentives to their staff, they may be better able to guide physician practice, and they might provide staff support to physicians so there is less leisure-based incentive to perform cesarean sections. In contrast, nongroup-model HMOs do not appear to reduce the incentive of physicians to maximize leisure relative to traditional insurance.

No exit? The effect of health status on dissatisfaction and disenrollment from health plans

OBJECTIVE

To examine the implications of serious and chronic health problems on the willingness of enrollees to switch health plans if they are dissatisfied with their current arrangements.

DATA SOURCE

A large (20,283 respondents) survey of employees of three national corporations committed to the model of managed competition, with substantial enrollment in four types of health plans: fee-for-service, prepaid group practice, independent practice associations, and point-of-service plans.

STUDY DESIGN

A set of logistic regression models are estimated to determine the probability of disenrollment, if dissatisfied, controlling for the influence on satisfaction and disenrollment of age, race, education, family income and size, gender, marital status, mental health status, pregnancy, duration of employment and enrollment in the plan, number of alternative plans, and HMO penetration in the local market. Separate coefficients are estimated for enrollees with and without significant physical health problems. Additional models are estimated to test for the influence of selection effects as well as alternative measures of dissatisfaction and health problems.

DATA COLLECTION

Data were collected through a mailed survey with a response rate of 63.5 percent; comparisons to a subsample administered by telephone showed few differences.

PRINCIPAL FINDINGS

In group/staff model HMOs and point-of-service plans, only 12-17 percent of the chronically ill enrollees who were so dissatisfied when surveyed that they intended to disenroll actually left their plan in the next open enrollment period. This compared to 25-29 percent of the healthy enrollees in these same plans, who reported this level of dissatisfaction and 58-63 percent of the enrollees under fee-for-service insurance.

CONCLUSIONS

Switching plans appears to be significantly limited for enrollees with serious health problems, the very enrollees who will be best informed about the ability of their health plan to provide adequate medical care. These effects are most pronounced in plans that have exclusive contracts with providers. We conclude that disenrollment provides only weak safeguards on quality for the sickest enrollees and that reported levels of dissatisfaction and disenrollment represent inaccurate signals of plan performance.

Survival and treatment for colorectal cancer Medicare patients in two group/staff health maintenance organizations and the fee-for-service setting

The current study compares treatment use and long-term survival in colorectal cancer patients between Medicare beneficiaries enrolled in two large prepaid group/staff health maintenance organizations (HMOs) and the fee-for-service (FFS) setting. The study is based on 15,352 colorectal cancer cases diagnosed between 1985 and 1992 and followed through 1995. Survival differences between the HMO and FFS cases were assessed using Cox regression. Treatment differences were evaluated using logistic regression. HMO cases had a lower overall mortality than did FFS cases but not a significantly lower colorectal cancer-specific mortality. Use of surgical resection was similar between HMO and FFS cases. However, rectal cancer cases in the HMOs were more likely to receive postsurgical radiation therapy than FFS cases. Superior overall survival in the HMOs may be the result of increased colorectal cancer screening, greater use of adjuvant therapies, and selection of healthier individuals.

Cause of death in men diagnosed with prostate carcinoma

BACKGROUND

Prostate carcinoma is one of the leading causes of death in men. Although the mortality rate is high, it still may underestimate the number of deaths associated with the disease. This study was conducted to compare causes of death among men previously diagnosed with prostate carcinoma and to examine the extent to which differences in cause of death (death from prostate carcinoma vs. death from other causes) varied by age, race, clinical factors, and comorbid conditions.

METHODS

A review was conducted of the medical records of decedent members of the Kaiser Permanente Medical Care program who previously were diagnosed with prostate carcinoma between January 1980 and December 1984 (n=584). The review focused on demographic factors, symptoms, diagnostic tests, stage of disease, and treatment. Data on comorbidity were obtained from a computerized discharge summary. Logistic regression analysis was used to estimate odds ratios.

RESULTS

Approximately 54% of the decedent prostate carcinoma patients died of their prostate carcinoma. Decedents who were black, age < or = 65 years, diagnosed with more advanced disease stage, recipients of hormonal therapy, and whose death occurred > 6 months after diagnosis were more likely than others to die of prostate carcinoma. In contrast, the likelihood of dying of some other cause was associated with concurrent cardiovascular disease, after adjustment for the effects of race, age, and disease stage. There also were significant two-way age-race and age-time-to-death interactions.

CONCLUSIONS

The prognostic significance of cardiovascular disease in prostate carcinoma patients should be investigated in subsequent survival studies. A number of questions need to be addressed delineating the complex relations between coexisting diseases and their treatment.

Optimizing capacity: the key to managed care success

Success in managed care boils down to capacity: Having the right number of physicians, doing the right things, at the right time, with the appropriate support staff. Capacity analysis can give physicians an accurate comparative view of their practice and help leaders make well-reasoned management decisions. Examples are included.

Practice or medical management: which key to success?

In the past, practice management systems were considered most important. Since revenues were based on fees for services rendered, the more patients and particularly procedures that could be scheduled in a day, the greater one's income. However, medical management systems are essential for the financial success of HMOs; these functions must also be present for the capitated group practice to be successful.

Flexibility key to group practice in the age of managed care

As changes in payment occur and managed care evolves, group practices are reclaiming influence over clinical care by assuming greater financial risk. Larger groups are becoming a force for change by using flexible structures to help improve a host of activities at the point of care. Group practices and their collaborative partners are refining their approaches to cooperative patient management, clinical utilization and quality, and risk contracting.

Study examines influence of PCP compensation method on cost, utilization of services

Data Insight: Opponents of risk contracting sometimes suggest that capitated provider withhold patient care to protect their own bottom lines. A recent study refutes that notion--with some qualifications.

The effect of increased prescription drug cost-sharing on medical care utilization and expenses of elderly health maintenance organization members

OBJECTIVES

The nature and extent of prescription drug benefits for the elderly are a continuing concern for health-care managers and policy makers. This study examined the impact of increased prescription drug cost-sharing on the drug and medical care utilization and expenses of the elderly.

METHODS

Two groups of well-insured Medicare risk-based members of a large health maintenance organization (HMO) had their copayments increased in different years during a 3-year period. Four 2-year analysis periods were established for comparing these elderly groups. During one analysis period, copayments did not change in either group.

RESULTS

Moderate increases of from $1 to $3, from $3 to $5 per copayment, and from 50% per dispensing to 70% per dispensing with a maximum payment per dispensing resulted in lower annual per capita prescription drug use and expenses. No consistent annual changes were observed in either medical care utilization (office visits, emergency room visits, home health-care visits, hospitalizations) or total medical care expenses across analysis periods.

CONCLUSIONS

No consistent relationships were observed between increased copayments per dispensing and medical care utilization and expense. Future research needs to address the impact on the classes of medications received and related health status, and the impact of larger increases in copayments per dispensing on medical care and health-related factors.

Referrals by general internists and internal medicine trainees in an academic medicine practice

Patient referral from generalists to specialists is a critical clinic care process that has received relatively little scrutiny, especially in academic settings. This study describes the frequency with which patients enrolled in a prepaid health plan were referred to specialists by general internal medicine faculty members, general internal medicine track residents, and other internal medicine residents; the types of clinicians they were referred to; and the types of diagnoses with which they presented to their primary care physicians. Requested referrals for all 2,113 enrolled prepaid health plan patients during a 1-year period (1992-1993) were identified by computer search of the practice's administrative database. The plan was a full-risk contract without carve-out benefits. We assessed the referral request rate for the practice and the mean referral rate per physician. We also determined the percentage of patients with diagnoses based on the International Classification of Diseases, 9th revision, who were referred to specialists. The practice's referral request rate per 100 patient office visits for all referral types was 19.8. Primary care track residents referred at a higher rate than did nonprimary care track residents (mean 23.7 vs. 12.1; P < .001). The highest referral rate (2.0/100 visits) was to dermatology. Almost as many (1.7/100 visits) referrals were to other "expert" generalists within the practice. The condition most frequently associated with referral to a specialist was depression (42%). Most referrals were associated with common ambulatory care diagnoses that are often considered to be within the scope of generalist practice. To improve medical education about referrals, a better understanding of when and why faculty and trainees refer and don't refer is needed, so that better models for appropriate referral can be developed.

Assessing the culture of medical group practices

This study was designed to identify the relevant components of the organizational culture of medical group practices and to develop an instrument to measure those cultures. Building on the work of industrial psychologists and organizational sociologists, a 35-item instrument was developed through an iterative process with more than 100 medical groups. The final instrument was tested using responses from physicians practicing in two very different medical groups: one a prepaid group practice with salaried physicians and the other, until recently, a fee-for-service practice. Using stepwise discriminant analysis of the responses to this instrument, more than 90% of the physicians were able to be placed in the appropriate practice setting.

Physician perspectives on the structure and function of group practice HMOs

This article explores physicians' perspectives regarding how their HMOs function and their satisfaction with and loyalty to HMOs. Three HMOs were studied: a mature (28-year-old) staff model, a 16-year-old staff model, and a 13-year-old group model with both HMO and fee-for-service patients. While these HMOs were found to vary somewhat in terms of emphasis on patient care versus costs, methods used to control costs and degrees of centralization of decision making, they all received high overall satisfaction and loyalty scores. The staff model HMO with a more decentralized decision making structure received the highest satisfaction/loyalty score from its physicians. The degree to which physicians perceive the HMO to be effective and supportive and the use of educational programs and peer review to influence resource use were also found to be significantly related to physician satisfaction and loyalty.

Office visit patterns in physician group practices

In summary, this study provides evidence that with as few as five diagnosis it is possible to identify some physician group practices that consistently treat patients with more or fewer visits, on average. However, even among group practices that vary considerably in size, location, and organizational structure, there is little deviation from the norm in terms of office visits. A study of more than 30 patients per site using data from both office records and insurance claims is needed, however, to examine the entire spectrum of treatment, including lab tests, special procedures, medications, and hospitalization. Such future studies may exploit the possibilities and avoid the pitfalls describes here to better characterize physicians' practice patterns.

Review of twenty years of research on medical care utilization

A wide variety of issues in social distribution and system performance are approached through analysis of utilization, as shown by this review of twenty years of research. Utilization studies have been used to examine social norms with respect to dying and to geographical and class diffusion of access to the most useful diagnostic procedures. Prevention utilization is selected for special study but is difficult to analyze because both the boundary between prevention and treatment services and the unit of observation are ill defined. A series of studies of the class gradient in use of care under conditions of reduced barriers to care indicate that equity can be improved through program design even though deficits remain at this time. For health plans with social objectives, a stable low-user group presents a challenge to outreach rather than a source of financial comfort. Other work on utilization examines unnecessary care through study of interregional variation in surgical rates and the phenomenon of physician-induced demand; cost-sharing; the HMO model in its attempt theoretically to reconcile equity with cost-containment; the role of sex differences in utilization; and the influence of women's social roles and traditional/contemporary cultural relationships on access.

Factors affecting choice of health care plans

The research reported here examined the factors which affected the decision to remain with either Blue Cross of Washington and Alaska or Group Health Cooperative of Puget Sound, or to change to an independent practice association (IPA) in which the primary care physicians control all care. The natural setting allowed examination of the characteristics of families with experience in structurally different plans; a decision not influenced by premium differentials; the importance of the role of usual provider; and a family-based decision using multivariate techniques. An expected utility model implied that factors affecting preferences included future need for medical care; access to care; financial resources to meet the need for care; and previous level of experience with plan and provider. Analysis of interview and medical record abstract data from 1,497 families revealed the importance of maintaining a satisfactory relationship with the usual sources of care in the decision to change plans. Adverse selection into the new IPA as measured by health status and previous utilization of medical services was not noted.

Supplemental health insurance coverage among aged Medicare beneficiaries

The goal of the National Medical Care Utilization and Expenditure Survey (NMCUES) of 1980 was to improve the understanding of the ways in which Americans use and pay for health care. This report is one in a series of descriptive reports based on NMCUES data. Data concerning insurance coverage were collected from household respondents in NMCUES. These data included the kind of insurance in effect for each person, the services covered, and the amounts paid by each source. In addition, the administration of private insurance plans and the kinds of charges covered were identified. The purpose of this report is to provide descriptive information about supplemental insurance coverage among the aged Medicare population with special emphasis on private supplemental health insurance coverage. For this report, supplemental insurance is defined as coverage (i.e., Medicaid, private, or other) in addition to Medicare and is to be distinguished from the Supplementary Medical Insurance part of Medicare that is known as SMI or Part B of Medicare. The results presented are based on data collected about the civilian, noninstitutionalized persons in the NMCUES national household sample who at any time during the survey year of 1980: (1) were 65 years of age or over, and (2) reported having been covered by Medicare Hospital Insurance (HI), or Medicare Supplementary Medical Insurance (SMI), or both. This report uses time-adjusted estimates that assign a single individual to different categories of insurance coverage according to the proportion of the year that he or she was covered by each kind of insurance. Consequently, estimates are made for person-years of coverage although they are expressed as persons for convenience. Approximately 4 out of 5 aged Medicare beneficiaries reported having some kind of insurance coverage in addition to Medicare during 1980. Approximately 67 percent of the aged Medicare population are estimated to have had private insurance in addition to Medicare; an estimated 13 percent had Medicaid. (Both of these estimates include 2.5 percent who reported Medicaid and private insurance simultaneously.) About 21 percent of the aged Medicare beneficiaries reported that Medicare was their only source of third-party coverage. The percentage of the aged Medicare beneficiaries who reported Medicare as their only source of third-party coverage was consistently 20 percent regardless of health status. However, the distribution among insurance categories of the remaining 80 percent who reported supplemental coverage of some type varied by health status. Medicare beneficiaries who were in poor health were much more likely to have Medicaid than Medicare beneficiaries who reported being in excellent health.(ABSTRACT TRUNCATED AT 400 WORDS)

A comparison of the treatment of rheumatoid arthritis in health maintenance organizations and fee-for-service practices

This study compares the use of health care services (hospital and ambulatory) by patients with rheumatoid arthritis who were under the care of rheumatologists in prepaid and fee-for-service arrangements. Participating physicians from a random sample of half the rheumatologists in northern California maintained a log of all their patients with well-established diagnoses of rheumatoid arthritis. We interviewed 822 of their patients, using a structured, validated phone survey to obtain information about health care use. Patients in prepaid plans had about the same number and type of hospitalizations and the same rate of surgery as those receiving fee-for-service care. However, fee-for-service patients made more ambulatory visits. We conclude that the use of expensive services (hospital admissions and surgery) for the care of patients with rheumatoid arthritis is not different in fee-for-service and prepaid settings.

Biased selection in Twin Cities health plans

The data in Tables 1 through 4 show significant differences in the enrollment of higher health-related financial risk individuals and their families among health plans. FFS enrollees are older and exhibit more chronic illness on average. IPAs enroll a greater proportion of females than do PGP or FFS plans. PGPs and IPAs do not differ significantly in the age and chronic illness of their enrollees, but IPAs enroll a significantly greater proportion of females than do PGPs. The age difference between FFS and prepaid plans appears to be greater for long-term enrollees. The same pattern is true of chronic illness, but the results are often not statistically significant. We do not have time-series data, however, and cannot conclude that future comparisons among long-term enrollees will remains as they are now. In any care our data do not support the hypothesis that biased selection is a short-term problem that will be corrected as the population in prepaid plans ages. Our data contain a cross-section of environments for health plans in firms: long- and short-term offerings, long- and short-term enrollees, high and low out-of-pocket premium costs, etc. Our strongest results are the simplest: across all plans and environments there are significant differences in enrollee characteristics. These differences would not be inefficient if all groups paid actuarially fair premiums. However, mandatory offering and community-rating allow prepaid plans to enroll a younger population with less chronic illness and to maintain an information asymmetry that prevents employers and employees from determining--either prior to or following enrollment--the relationship of the prepaid plan's premium to its marginal cost.

A controlled trial of the effect of a prepaid group practice on use of services

Does a prepaid group practice deliver less care than the fee-for-service system when both serve comparable populations with comparable benefits? To answer this question, we randomly assigned a group of 1580 persons to receive care free of charge from either a fee-for-service physician of their choice (431 persons) or the Group Health Cooperative of Puget Sound (1149 persons). In addition, 733 prior enrollees of the Cooperative were studied as a control group. The rate of hospital admissions in both groups at the Cooperative was about 40 per cent less than in the fee-for-service group (P less than 0.01), although ambulatory-visit rates were similar. The calculated expenditure rate for all services was about 25 per cent less in the two Cooperative groups (P less than 0.01 for the experimental group, P less than 0.05 for the control group). The number of preventive visits was higher in the prepaid groups, but this difference does not explain the reduced hospitalization. The similarity of use between the two prepaid groups suggests that the mix of health risks at the Cooperative was similar to that in the fee-for-service system. The lower rate of use that we observed, along with comparable reductions found in non-controlled studies by others, suggests that the style of medicine at prepaid group practices is markedly less "hospital-intensive" and, consequently, less expensive.

Policy implications of startup utilization by enrollees in prepaid group plans

This article discusses several policy implications of the so-called startup effect, in which high initial health services utilization by new enrollees in prepaid group plans ( PGPs ) becomes reduced with the increasing duration of membership. Results of research in a developing PGP are analyzed as they relate to a mathematical model of startups for two measures of enrollee use. After estimating the total costs of startups in this setting, the motivating effects of such costs on PGPs are examined in relation to several policy issues--including the rate of PGP development in the United States, the use of financial incentives to enroll the elderly and medically disadvantaged, potential inequities of premium determination, the large impact of startups on disenrollment , and the federally mandated process of annual announcement of benefits and open enrollment. Ideas and mechanisms for future study on the startup effect and its policy implications are discussed.

A rural primary health care service in Israel--some measures of utilization and satisfaction

Measures of use and satisfaction within a rural health service in Israel were surveyed in a study of the anonymous responses to a questionnaire from 110 mothers of children 14 years of age and younger in two agricultural villages. The majority of mothers expressed satisfaction with the health service, although there were notable reservations about the availability of certain services. Differences were detected between the reasons mothers recorded for initiating contacts with the medical team and the actual day-to-day experience of the health team members. Satisfaction with the service was associated with the length of the waiting time to see the physician, the perceived sufficiency of time the physician spent on the examination, and awareness that the physician was on call after clinic hours for the survey population. It was also found that the combined hospital use for the populations of 10 surrounding villages was almost twice that of the study villages. The findings are discussed in the context of both the immediate impact on the health service studied and the wider implications for primary health care in Israel. These include an identification of the health service with the physician and the potential medical and economic benefits of continued responsibility for care after clinic hours.

Use of ambulatory care services in three provider plans: interactions between patient characteristics and plans

A previous study of low-income enrollees in a closed-panel health maintenance organization (HMO) and a Blue Cross/Blue Shield (BC/BS) plan showed that the effect on the use of health services of the age, sex, health status, previous health care use, race, and family size of the enrollees was different in the two plans. We have replicated this study using the same two provider plans but studying a different group of white collar, middle class enrollees. A third plan, an experimental independent practice association (IPA), was also available for analysis. Utilization was defined as use (yes/no) and the quantity of use for those who used services (in standardized dollars). Significant interactions were detected between plan and all of the independent variables but race. The use of services in the HMO was least affected by enrollees' characteristics (age, sex, race, health status, prior use, family size) and use was most sensitive to patient characteristics in BC. In some respects, the IPA was more like the HMO and in other respects more like the BC/BS plan.

Disenrollment from a prepaid group plan. A multivariate analysis

Although high annual disenrollments from prepaid group practices (PGPs) present significant problems to the manager, studies on this subject generally have been limited to simple descriptions of the phenomenon. The authors' approach utilizes multivariate techniques--discriminant analysis and logistic regression--to overcome the simplicity of these bivariate studies. It allows an examination of the significant correlates of disenrollment in a stepwise manner that adjusts for the effects of all variables included in the models. Two surveys conducted by the Medical Care Group of St. Louis (MCGSL) provide data for this research. After classifying the sample of 2,402 families as continuous enrollees, voluntary disenrollees, and mandatory disenrollees, the analyses show that these groups represent significantly different member populations. The variables that significantly and independently discriminate among them include sociodemographic characteristics (subscriber age, race, education and occupation, and family size and income), satisfaction level with the plan, and presence of alternatives to the PGP (nonplan family members and coverage by alternative health insurance). These findings suggest that voluntary and mandatory disenrollment behavior may be more complex than previously considered. Moreover, the PGP manager is faced with perplexing problems in attempting to control this troublesome phenomenon.