The American Journal of Managed Care January 2011
High-Deductible Health Plans and Costs and Utilization of Maternity Care
Objective: To evaluate the impact of switching from an HMO to a high-deductible health plan on the costs and utilization of maternity care.
Study Design: Pre-post design, with a control group.
Methods: We compared 229 women who delivered babies before or after their employers mandated a switch from HMO coverage to a high-deductible health plan, with a control group of 2180 matched women who delivered babies while their employers remained in an HMO plan. Administrative claims from a large Massachusetts-based health insurance program were used in a difference-indifferences regression analysis.
Results: Mean out-of-pocket maternity care costs for high-deductible group members increased from $356 for women who delivered before the insurance transition (n = 86) to $942 for women who delivered after the transition (n = 143), compared with a change from $262 (n = 711) to $282 (n = 1569) for HMO members, a relative increase of 106% (P <.001) for high-deductible members. Delivery after transition to a high-deductible plan was not associated with changes in the odds of receiving early prenatal care (odds ratio [OR], 1.02; 95% confidence interval [CI], 0.32-3.19), recommended prenatal visits (OR, 1.64; 95% CI, 0.89-3.02), or postpartum care (OR, 0.74; 95% CI, 0.42-1.32).
Conclusions: Switching from an HMO to a high-deductible plan with exemptions for routine care increased out-of-pocket member costs for maternity care, but had no apparent adverse impacts on receipt of recommended prenatal and postpartum care.
(Am J Manag Care. 2011;17(1):e17-e25)
Transition from an HMO to a high-deductible health plan with deductible exemptions for routine preventive maternity services was associated with:
- Substantial increases in out-of-pocket expenses for maternity and delivery-related care (although information on changes in employer account contributions and employee premium contributions was not available).
- A statistically insignificant (but large) reduction in overall costs.
- No apparent adverse impacts on recommended prenatal and postpartum care.
Although HDHPs are intended to decrease escalating health costs and discretionary care, they have generated controversy.8-12 High cost sharing can reduce appropriate healthcare utilization, including hospitalizations, preventive services, and essential medicines.13-15 Therefore, HDHPs often fully cover preventive services, including prenatal care.16-19 No previous studies have measured the impact of HDHPs on the costs and use of maternity care.20,21
Our study examined this question among women insured by a large Massachusetts-based health insurance program (Harvard Pilgrim Health Care) that predominantly insures members through HMO plans and began offering HDHPs in April 2002. We anticipated that HDHP membership would increase out-of-pocket maternity expenditures, shift costs to members, and possibly reduce total maternity care expenditures, consistent with the cost-containment goal of consumer-directed healthcare.22
Although use of exempted services might be expected to remain stable, we hypothesized 3 mechanisms that could decrease utilization. (1) Cost sharing for nonexempt services (such as laboratory tests) ordered during prenatal visits could discourage subsequent visits. (2) The intricacy of maternity benefit design in HDHPs (eg, deductible exemptions based on clinical conditions) combined with uncertainty regarding costs of anticipated services could cause confusion and reduced care even for exempt services.9,23 (3) Experiencing a previous large deductible payment (eg, an emergency department visit) might induce “sticker shock” and broadly reduce utilization.24
The objective of this study was to evaluate the impact of transition from an HMO to an HDHP on the costs and utilization of maternity and delivery care services within the 6 months before and 3 months following delivery.
The Office for Sponsored Programs (Harvard Pilgrim Health Care Institute) reviewed this study and granted institutional review board approval.
We used a pre–post study design with matched control group and a difference-in-differences analysis to measure changes in study outcomes.
Harvard Pilgrim Health Care is a health plan serving approximately 1 million individuals in New England. On April 1, 2002, Harvard Pilgrim began offering HDHPs with annual deductible amounts of $500 to $2000 for individuals and $1000 to $4000 for families. Members of family plans also had individual deductibles equal to half of the family deductible. Of Harvard Pilgrim’s commercially insured members, approximately 70% have HMO plans, 20% have preferred provider organization (PPO) plans, and 10% have HDHPs, compared with corresponding national rates of 58%, 19%, and 13%.4 Although PPO plans are more common than the HMO plans we study, cost-sharing requirements for services such as preventive tests, hospitalizations, and specialist visits are quite similar4; the primary differences between HMO and PPO plans are the more limited provider network, the need for specialist referrals, and the inclusion of high deductibles in approximately 40% of PPO plans.4
Insurance coverage for maternity care in Harvard Pilgrim HMO plans includes full coverage of prenatal and postpartum care, with no cost sharing beyond office visit and hospitalization copayments. Outpatient visit copayments among HMO members in our study ranged from $5 to $25 (median $15) while hospitalization copayments ranged from $0 to $1000 (median $250).
In the HDHPs we studied, many maternity care services are exempt from the deductible, having either first dollar coverage or low copayments. First dollar coverage applies to routine prenatal and postpartum visits, fetal ultrasounds (sonograms), routine urinalysis, Papanicolaou tests, and screenings for sexually transmitted infections. All hospital delivery charges and many outpatient procedures are subject to the deductible, but are covered in full after the deductible has been met. Copayments of $20 apply to non–maternity care outpatient visits, urgent care visits, and specialist consultations. These copayments apply regardless of whether the member has exceeded the deductible spending level. However, the HDHPs have an out-of-pocket maximum (including copayments and deductibles) of $2000 to $4000 for individuals and $4000 to $8000 for families. After a member reaches the out-of-pocket maximum, all services are covered in full. Provider networks for women in HDHPs and HMO plans are identical.
The HDHPs we studied were not eligible to be paired with health savings accounts (HSAs); all were eligible to be combined with health reimbursement accounts (HRAs). Although we could not account for HRA purchases from other companies, only 3% of the HDHPs we studied had HRAs through Harvard Pilgrim. Nationally, fewer than half of HDHPs with deductibles over $1000 are paired with HSA or HRA accounts,4 so our analysis is relevant for the predominant type of HDHP.
Using previously established methods,24 we created a cohort of health plan members enrolled through employers who exclusively offered insurance through Harvard Pilgrim Health Care. We defined 2 cohorts: an HDHP group and an HMO control group. The HDHP group included members enrolled in traditional HMO plans during a 1-year baseline period prior to an employer-mandated switch to an HDHP. The date of this switch was defined as the index date. For each HDHP member, we identified 8 contemporaneous members who were continuously enrolled in traditional HMO plans during the same time period. We assigned HMO controls the same index date as their HDHP counterparts, and the distribution of index dates was similar in the HDHP and HMO control groups in the final study population. We selected only HMO members whose employers did not offer an option to enroll in an HDHP or any other plan types. Therefore, no study members were able to self-select their health insurance plan or benefits structure.
From the HDHP and HMO groups, we identified women who had given birth using International Classification of Diseases, Ninth Revision diagnosis codes and diagnosis-related group payment codes. We further divided the study cohorts based on whether each woman delivered a baby prior to or following the index date. The final study population included 2409 women who delivered babies between October 1, 2001, and November 30, 2007. This population included 229 women in the HDHP group (86 delivered prior to the index date and 143 after) and 2180 women in the HMO control group (711 delivered prior to the index date and 1569 after). Among women in the HDHP group, 95 had a $500 deductible, 92 had a $1000 deductible, and 34 had a $2000 deductible (values unavailable for 8 women). The study used data from 6 months prior to and 3 months following delivery (the second and third trimesters of pregnancy and early postpartum period).
Study outcomes included costs, quality, and utilization, categorized as delivery related (for care provided during the delivery hospitalization) and maternity related (for all types of maternity care, including delivery-related care). Cost measures included out-of-pocket and total expenditures. Out-of-pocket costs comprised all member expenditures toward copayments and deductibles. Total costs were calculated as the sum of the expenditures by the insurer (payer costs) and out-of-pocket expenditures by the member.
We calculated maternity and delivery-related costs using a previously established set of diagnosis, procedure, and payment codes that included prenatal and postpartum visits, obstetrical anesthesia, introduction and repair services, vaginal or caesarean delivery, radiology procedures, pathology and laboratory expenses, and in utero procedures.3 We distinguished delivery services from non–delivery-related maternity care both by the specific service and procedure codes and by the timing of occurrence during the delivery hospitalization. Measures of maternity care quality included 3 measures based on Healthcare Effectiveness Data and Information Set (HEDIS) indicators (early prenatal care, appropriate frequency of prenatal care, and timely postpartum care).25 Early prenatal care was defined as having at least 1 prenatal visit within 42 days of the second trimester. Appropriate frequency of prenatal care comprised at least 7 prenatal visits in the 190 days prior to delivery, as per consensus recommendations.26 We calculated this measure only among women who delivered full-term babies (>37 weeks of gestation) due to lack of information on gestational age at delivery for preterm infants. Timely postpartum care was achieved by having a visit between 21 and 56 days after delivery. General maternity care utilization measures included the total number of prenatal visits and sonograms, and the length of stay for the delivery hospitalization.
Other variables were age at delivery, month of delivery, type of delivery (vaginal or caesarean), gestational diabetes, high-risk pregnancy, preterm delivery, chronic disease score, socioeconomic status, and employer size (number of employees). Clinical conditions were defined using payment or diagnosis codes. As a measure of comorbidity and care-seeking behavior, we computed the chronic disease score, which predicts future healthcare spending based on pharmacy claims in the baseline year.27 To develop a measure of socioeconomic status, we linked members’ residential addresses to their 2000 US Census block group and created measures of neighborhood education levels and poverty status based on previously established standards.28 Low socioeconomic status was indicated by living in a census block group with either more than 25% of adults having less than a high school education or more than 10% of households living below the poverty level.
We used regression models in a difference-in-differences analysis to assess the independent effect of switching to an HDHP on costs, quality, and utilization outcomes, after controlling for the covariates listed above. This analysis used 3 types of regression models: log-linear for costs, logistic for dichotomous quality measures, and linear for utilization measures (number of visits or days). We also conducted several sensitivity analyses to test the stability of results. Analyses excluding socioeconomic status (which is measured at the census block level rather than the individual level) and adjusting for inflation (using the medical component of the Consumer Price Index) had no impact on the direction or significance of the original findings.
All statistical analyses used 2-tailed tests and a levels of .05, and were conducted using SAS version 9.1 (SAS Institute Inc, Cary, NC).