BACKGROUND: Evidence-based clinical preventive services are underutilized. We explored the major factors associated with delivery of these services in a large physician-owned community-based group practice that provided care for both fee-for-service (FFS) and health maintenance organization (HMO) patient populations.
METHODS: We performed a cross-sectional audit of the computerized billing data of all adult outpatients seen at least once by any primary care provider in 1995 (N = 75,621). Delivery of preventive services was stratified by age, sex, visit frequency, insurance status (FFS or HMO), and visit type (acute care only or scheduled preventive visit).
RESULTS: Insurance status and visit type were the strongest predictors of clinical preventive service delivery. Patients with FFS coverage received 6% to 13% (absolute difference) fewer of these services than HMO patients. Acute-care-only patients received 9% to 45% fewer services than patients who scheduled preventive visits. The combination of these factors was associated with profound differences.
CONCLUSIONS: Having insurance to pay for preventive services is an important factor in the delivery of such care. Encouraging all patients to schedule preventive visits has been suggested as a strategy for increasing delivery, but that is not practical in this setting. Assessing the need for preventive services and offering them during acute care visits has equal potential for increasing delivery.
Preventive care to the well patient has become an accepted activity in primary care.1 Clinical preventive services require a high standard of proof of effectiveness.2 Although evidence-based guidelines1 and goals3 have been published, optimal delivery has been achieved only infrequently.4 The formidable list of its potential barriers4 includes physician factors (lack of consensus, motivation, compensation, time), patient factors (age, race, sex, patient acceptance, insurance status, visit frequency, not scheduling preventive visits), and system factors (absence of paramedical assistance, disorganized medical records, fragmentation of care, lack of a systematic delivery program). Strategies to improve the delivery of preventive services must recognize the complexity and uniqueness of each office practice5-7 and advocate the use of quality improvement methodologies.8
Previous studies have shown that insurance coverage significantly affects preventive service delivery,9 but the fear that health maintenance organization (HMO) patients would receive fewer preventive services than fee-for-service (FFS) patients10 is unfounded.11 The favorable effect of HMO enrollment on preventive service delivery is probably because of insurance coverage rather than self-selection.11 Many studies of FFS and HMO care delivery have compared one physician group seeing FFS patients exclusively with another group seeing HMO patients.12-18 In that study design, differences may be related to confounding physician and system factors rather than the type of insurance coverage.19
Physicians have been trained to deliver preventive care during the annual complete physical examination. The effectiveness of the traditional complete physical as a vehicle for preventive service delivery has been questioned recently,20 however, and delivery of preventive services during acute care visits has been advocated as a more effective alternative.21,22 Indeed, systematic delivery strategies that include the offer of these services during acute care visits have achieved the highest levels of preventive service delivery in primary care settings.4,23 But these studies were performed in a small number of private practice settings, and it is unclear whether the same results apply in the larger organized systems of care.24
As part of a program to increase delivery of adult clinical preventive services, we determined the major factors associated with the performance of specified preventive services in a large physician-owned health delivery system that included both HMO and FFS patients. We particularly sought to measure the quantity of preventive services associated with insurance status (HMO vs FFS) and visit type (preventive visits vs acute care only).
Methods
Practice Setting
We studied a multispecialty group practice with 15 offices located in Dane County, Wisconsin. The service area is representative of the county and contains one midsize city (190,000 population), several smaller cities and towns, and a surrounding rural area. During the audit period there was a county population of 351,362, of whom 149,225 (42%) were enrolled in HMOs, 7027 (2%) were covered by Medicaid, and 42,193 (12%) were uninsured. The group practice owned and operated its own prepaid health plan (DeanCare HMO), which was clinically managed by the physician-owners who were compensated for their services on the basis of a discounted FFS formula that did not provide financial incentives to manage HMO and FFS patients differently. The HMO paid for all preventive services deemed appropriate by the physician, while many FFS insurance carriers did not.
Audit of Computerized Billing Records
The group practice computerized billing system contained a record for every encounter. The records include provider and patient codes, the site of service, diagnosis codes, and any billable tests obtained within the group’s clinical laboratory and radiology facilities. Only group practice sites that used these facilities exclusively were audited. Patient demographic information was obtained by cross-referencing the patient code with a master enrollment file. Computerized billing data for 1985 to 1995 were audited. For each patient, yearly data were abstracted that included a flag for the presence/absence (1/0) of a billable preventive procedure. From this data file, a set of positive criteria was constructed to determine the prevalence of preventive service delivery on the basis of age, sex, and frequency criteria Table 1. Positive criteria were modeled after those developed by the National Committee on Quality Assurance.25