Does Patient Cost Sharing Matter? Its Impact on Recommended Versus Controversial Cancer Screening Services

Published Online: February 01, 2004
Su-Ying Liang, PhD; Kathryn A. Phillips, PhD; Sherilyn Tye, PhD; Jennifer S. Haas, MD, MSPH; and Julie Sakowski, PhD

Objective: To examine whether there are differential impacts of patient cost sharing and health plan organizational characteristics on the use of a recommended cancer screening service (mammography) versus a controversial cancer screening service (prostate cancer screening [PCS]).

Study Design: Observational cohort using the 1996 Medical Expenditure Panel Survey.

Patients and Methods: A nationally representative sample of privately insured individuals was examined. Outcome measures were the receipt of mammography and PCS. Logistic regression was used to assess the impact of patient cost sharing and health plan organizational characteristics on the receipt of mammography and PCS, controlling for other covariates.

Results: Patient cost sharing and gatekeeper requirements were strong predictors of PCS but were statistically insignificant predictors of mammography. Men in health plans with a copayment over $10 (odds ratio [OR] = 0.38, 95% confidence interval [CI] = 0.19- 0.78) or with deductibles over $250 (OR = 0.38, 95% CI = 0.23- 0.62) were significantly less likely to receive PCS than men in plans with no or lower copayments and deductibles. Men in gatekeeper plans were less likely to receive PCS than those without gatekeepers (OR = 0.48, 95% CI = 0.29-0.81).

Conclusions: We found the impact of cost sharing on utilization is different between mammography and PCS. Prostate cancer screening utilization appears to respond to financial incentives while mammography utilization does not. The use of copayments, deductibles, and gatekeepers may discourage controversial services but may not have an adverse effect on more recommended services. These findings have implications for the design of insurance benefits and plan organizational structure.

(Am J Manag Care. 2004;10(part 1):99-107)

It has long been recognized that health insurance reduces the effective price of medical services that patients face and may thereby result in overutilization of services. An increasing number of health insurers have adopted patient cost sharing mechanisms to curb utilization and to control the rising costs of healthcare. Numerous studies have attempted to assess the impact of such cost sharing strategies on the use of a wide range of medical services, including physician visits and hospital admissions, office-based medical care, mental health services, emergency department use, preventive care, vision care, dental care, and chiropractic services.1-12 Findings from the RAND studies and others based on community data are generally consistent with economic theory predicting that patient cost sharing reduces the use of medical services.

Although earlier research has improved our knowledge of whether and to what extent cost sharing influences the use of health services, it is also important to evaluate whether its effect differs for the use of recommended versus controversial medical services. A meaningful inquiry is how patient cost sharing influences the use of healthcare: does cost sharing improve consumption efficiency by reducing the use of inappropriate services or does it create another dimension of distortion by reducing the use of appropriate services?

Despite its importance, literature on this topic is very limited. Only a few studies have examined whether the influence of cost sharing differs for the use of appropriate and inappropriate care. Siu et al analyzed data from the RAND Health Insurance Experiment (HIE) to determine whether cost sharing disproportionately reduces inappropriate hospital admissions and hospital stay.13 These authors found that cost sharing decreased both inappropriate, as well as appropriate hospital use. Foxman and colleagues, also using the data from the RAND HIE, found that the impact of cost sharing on inappropriate and appropriate antibiotic use was similar.14

Rather than analyzing the appropriate and inappropriate use of services, the objective of this study was to examine whether there is a differential impact of cost sharing on the use of recommended and controversial cancer screening services. We used data from the 1996 Medical Expenditure Panel Survey (MEPS) to analyze mammography and prostate cancer screening (PCS) utilization. Mammography is a widely recommended screening test because of substantial evidence that it is associated with reduced breast cancer mortality.15 In contrast, PCS is more controversial, with no consensus about its efficacy or recommendations.15,16 The analysis of mammography and PCS provides an interesting comparison as to whether the impact of cost sharing differs between recommended and controversial cancer preventive services. We hypothesized that patients (and possibly providers) would be more cost conscious in their decisions to use (or encourage) controversial services as compared with recommended services. Our study adds to the literature by extending this line of research to preventive services and by updating the empirical evidence using a more recent dataset that approximates today's healthcare environment.

This study also contributes to the literature on cancer screening utilization by examining the association between a comprehensive set of health plan characteristics. Most of the other studies that have investigated the association between plan characteristics and cancer screening have used broad categories of insurance (eg, managed care vs fee-for-service plans or health maintenance organizations (HMOs) vs non-HMOs).17-19 More recent studies have shown that the distinctions between these broad plan classifications are blurring and what may be most important predictors are specific characteristics of the plan.20-22 In this study, we examine several specific plan characteristics, including patient cost sharing (eg, copayments, deductibles, and coinsurance rates), as well as organizational characteristics such as having a defined provider network and requirements for the use of gatekeepers.

Our study provides interesting empirical evidence on how cost sharing influences the use of preventive care and has policy implications for practice and insurance benefit design. To our knowledge this is the first study to analyze the association between cost sharing and PCS utilization. It is also the first to investigate whether there is a differential impact of cost sharing on the use of 1 strongly recommended screening service versus a more controversial cancer screening procedure.


Data Sources

The primary data source for this study was from the 1996 MEPS-Household Component (HC). MEPS is an ongoing survey sponsored by the Agency for Healthcare Research and Quality and is designed to provide nationally representative data on the demographic characteristics, health status, healthcare use, access to care and insurance status of the US civilian, noninstitutionalized population.23 The Health Insurance Plan Abstraction (HIPA) component of the 1996 MEPS contains detailed information on the private insurance plans obtained from health plan booklets. Despite its age, the potential to analyze detailed health insurance data collected directly from plan documentation linked to individual characteristics and healthcare utilization information makes the 1996 MEPS data the most comprehensive data currently available for the purposes of this study.

The secondary data used for this analysis included the 1995 National Health Interview Survey (NHIS). Individuals' physician visit information in 1995 was linked to 1996 MEPS to allow us to examine the association between physician visits and the use of cancer screening procedures over a 2-year period. The linkage between these 2 datasets is made possible because the 1996 MEPS sample is drawn from a subset of respondents to the 1995 NHIS.


Our study sample included privately insured adults from the MEPS-HC who were linked to HIPA (unweighted, n = 13 534).

Dependent Variables

We examined a widely recommended preventive service, mammography, and a more controversial preventive service, PCS. In 1996, the US Preventive Services Task Force (USPSTF) strongly recommended routine screening for breast cancer with mammography every 1-2 years for women between the ages of 50-69, and suggested that screening for women aged 70-75 may be reasonable because of high burden of suffering from breast cancer despite limited evidence supporting screening for this age group. Most concur that screening mammography every 1-2 years in women aged 50 and over can reduce breast cancer mortality.24 We therefore examined the self-reported receipt of mammography screening within the past 2 years for women aged 50 and older, without a prior history of breast cancer.

Routine screening for prostate cancer is not recommended by the USPSTF. Other organizations, however, recommend prostate cancer screening, including the American Cancer Society, the American Urological Association, and others. These organizations suggest that men without a family history of prostate cancer undergo an annual prostate specific antigen screening over the age of 50.24-26 We examined the self-reported receipt of prostate cancer screening within the past 2 years for men ages 50 and older, without a prior history of prostate cancer.

Independent Variables

Predictors of mammography and PCS examined in this study include characteristics of patients, providers, and health plans. The primary independent variables of interest for this study were patient cost sharing and organizational characteristics of a health plan (Table 1). Since a number of patient and provider characteristics have already been identified in the literature as being associated with the utilization of cancer screening services, they are controlled for in our model as well. Patient cost sharing measures included in our model were copayment, deductible, and coinsurance. Health plan organizational characteristics included measures of a defined provider network, gatekeeper requirements, and the use of cost-containment procedures. The measures of patient cost sharing and cost containment strategies were based on health plan booklet data. Information on provider network and gatekeeper requirements was available through both plan booklets and self-report data. Measures from both self-reported and plan documentation for network and gatekeeping requirements were used because perceptions of plan characteristics may have more influence on the behavior of healthcare utilization than the actual plan characteristics. 27

Table 1

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