The American Journal of Managed Care February 2009
The Effects of Antihypertensive Step-Therapy Protocols on Pharmaceutical and Medical Utilization and Expenditures
Step therapy with antihypertensives may lead to medication cost savings but may have unintended effects on other medical care utilization and spending.
Objective: To examine the effects of antihypertensive step therapy on prescription drug utilization and spending, and other medical care utilization and spending.
Study Design: Pre/post design.
Methods: Employers who had implemented step therapy were compared with employers who had not implemented step therapy. Data were drawn from the 2003 through 2006 MarketScan Research Databases. The study sample included employees and dependents who used antihypertensives (11,851 patients whose employer implemented a step-therapy protocol and 30,882 patients in the comparison group without step therapy). Multivariate generalized estimating equation models were used to estimate the immediate and timevarying effects of step therapy on medical and prescription drug spending and utilization, while controlling for important covariates and adjusting for clustering by patient.
Results: Results showed an initial 7.9% reduction in antihypertensive medication days supplied and an initial 3.1% reduction in medication costs among antihypertensive users in the step-therapy plans. However, these percentages grew in each subsequent quarter. Antihypertensive users in step-therapy programs also experienced an increase in inpatient admissions and emergency room visits. After an initial decline in spending, the step-therapy group incurred $99 more per user in quarterly expenditures than the comparison group.
Conclusions: The intended effect of step therapy is to substitute cheaper and equivalently effective medications for more expensive medications. As this study demonstrates, step therapy may create barriers to receiving any medication, resulting in higher medical utilization and costs. Further research is needed to understand why these unintended consequences occur and how they might be avoided.
(Am J Manag Care. 2009;15(2):123-131)
This study examined the effects of step therapy on prescription drug, inpatient, and emergency room utilization and spending among users of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Although step therapy led to medication cost savings, it also had unintended consequences:
- The number of days supplied for antihypertensives declined.
- The number of people discontinuing therapy increased immediately after step therapy was implemented.
- Inpatient and emergency room admissions and costs were higher in step-therapy programs.
There is a small but growing literature on step-therapy programs. In 2007 Yokoyama and colleagues evaluated hypertension-related pharmacy use and costs for 3 managed care plans that implemented an angiotensin receptor blocker (ARB) step-therapy intervention compared with 1 health plan with no ARB step-therapy intervention.2 The step-therapy intervention used a smart edit of patient pharmacy claim history in the preceding 3-month period. The ARB claim was rejected if there was no prior use of these drugs, in which case the pharmacist or patient had to contact the prescriber to obtain an alternative to the ARB or a prior authorization. The researchers found that within 12 months of follow-up, a step-therapy intervention for ARBs was associated with an 18% ratio of ARB users to the total number of patients using angiotensin-converting enzyme (ACE) inhibitors or ARBs compared with a 31% ratio in a health plan without the ARB step-therapy intervention. Of the patients who attempted to obtain an ARB and were rejected in the step-therapy group, 44.6% of patients went through the prior authorization process and received an ARB as initial therapy, 48.8% received other antihypertensive therapy, and 6.6% did not receive any antihypertensive therapy. Antihypertensive drug costs were about 13% lower for the ACE/ARB patients in the intervention group.
Motheral and colleagues examined the effect of prescription step-therapy programs in terms of plan-sponsor savings and member experience at the point of service.3,4 Specifically, they studied a 20,000-member plan that implemented 3 step-therapy programs in September 2002. The step-therapy programs covered proton pump inhibitors, selective serotonin reuptake inhibitors, and nonsteroidal anti-inflammatory drugs. Pharmacy claims from September 1, 2001, through June 30, 2003, were examined to compare changes in pharmacy per-member per-month (PMPM) net cost for the intervention group with changes in pharmacy PMPM net cost for a random sample of members from commercial plans without the step-therapy programs. A mailed, self-administered survey was sent to members with a step edit from September 1, 2002, through December 31, 2002. They found that the employer experienced a decrease of $0.83 PMPM in net cost after implementing step therapy, while the comparison group had an increase of $0.10 PMPM for these therapy classes.
Of the approximately 657 members who experienced a step-therapy edit and were mailed a survey, 33% returned the survey. Member-reported outcomes indicated that approximately 30% of patients received a generic after the step-therapy edit, 23% were granted a medical exception for the brand, and another 16% paid out-of-pocket for the brand medication. Nearly 17% received no medication, and another 10% received a sample or a nonprescription alternative. Compared with those who received first-line therapy, those who paid out-of-pocket for the brand medication and those who did not receive any medication were less likely to be satisfied with their pharmacy benefit.4
Dunn and colleagues evaluated the impact on utilization and costs of a generic step-therapy program for antidepressant drugs in a health maintenance organization.5 In the program, brand-name antidepressants were covered only after a trial with a generic antidepressant, excluding tricyclic antidepressants. The authors found that the generic antidepressant dispensing rate increased by 20 percentage points (32.5%-52.5%) in the intervention group but only 7.4 points in the comparison group (24.9%-32.3%). Antidepressant costs per day of therapy in the intervention group decreased 11.7% versus a 2.7% decrease in the comparison group. The combination of change in drug costs and utilization resulted in a 13% decrease in antidepressant drug costs, from $4.16 PMPM in 2004 to $3.62 PMPM in 2005, versus a 7.6% decrease (from $3.57 to $3.30 PMPM) in the comparison group.
While prior research examined the effects of step therapy on prescription drug utilization and spending, this study focused on the effects of step therapy on all types of medical care utilization and spending. Specifically, the goal of this study was to examine the impact of a step-therapy program for ACE/ARBs on prescription drug and medical utilization and spending. Our estimates of the effects of step therapy are based on 2 ACE/ARB step-therapy programs implemented at different points in time, not a single program implementation. This strengthens the study design, providing an estimate of the common effects of step-therapy programs on utilization and spending.
The data source is the MarketScan Research Database from Thomson Reuters, representing the healthcare experience of enrollees in employer-sponsored health plans in the United States. Although the MarketScan Database in its entirety represents the healthcare experiences of more than 60 employers, we selected employers who had either (1) recently implemented step therapy (as a treatment group) or (2) could be verified as not having a step-therapy program in place (as a comparison group). Two firms had recently implemented steptherapy programs and were selected as the treatment group. As an additional requirement, the step-therapy program had to be implemented equally across all benefit plans available to an enrollee. To reduce the likelihood of selection bias, step therapy could not be selected or deselected by the individual enrollee. Two employers that did not have a step-therapy program in effect during the same time served as a control group.
The step-therapy programs identified were implemented at different times, from 2003 through 2005, depending on the particular employer and prescription drug class. Exact dates of implementation are not disclosed to protect the identities of the employers.
This analysis focuses on step-therapy programs for antihypertensive medications because these are among the most commonly used medications. Two employers in the study implemented step therapy for antihypertensives, in particular ACE inhibitors and ARBs. The step-therapy program required certain (first-level or preferred) ACE inhibitors or ARBs to be used for a period of time (eg, 130 days) before using another (second-level) ACE inhibitor or ARB. Both step-therapy programs included the same antihypertensive medications for steps 1 and 2:
Step 1: benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, Quinaretic.
Step 2: Atacand, Avalide, Avapro, Benicar, Cozaar, Diovan, Hyzaar, Micardis, Teveten.
The sample was limited to employees and dependents of the selected employers (step-therapy and comparison group) who were continuously enrolled from 2003 through the third quarter of 2006, under 65 years of age, and not eligible for Medicare. An analytic file was created using a panel data (repeated measures) framework with 1 observation each quarter for each individual. Each enrollee in the analytic file had 15 observations (ie, quarters of data). The total sample comprised 269,561 enrollees. Of this group, 66,308 were enrolled in step-therapy plans and 203,253 were enrolled in comparison plans. We also focused on the subset of enrollees in each plan who were antihypertensive users (N = 42,733). Of these, 11,851 were in step-therapy plans and 30,882 were in comparison plans.
The dependent variables were prescription drug and medical costs and utilization. Six quarterly utilization measures were examined for antihypertensive users: the number of antihypertensive (ACE/ARB) days supplied (within the time period covered by the quarter), the antihypertensive (ACE/ARB) discontinuation rate (as defined by a gap of at least 60 days with no evidence of use of any drug in the class), the number of prescriptions filled, the number of emergency room visits, and the number of inpatient admissions. Five spending measures for antihypertensive users were examined: outpatient prescription drug, emergency room, inpatient medical (admissions), outpatient medical (nondrug), and total (medical and drug). Expenditures were defined as the total amount reimbursed to providers from all sources of payment including the health plan, the patient, and any third party (coordination of benefits amount). One utilization measure was examined for all enrollees: the antihypertensive (ACE/ARB) days supplied.
Statistical evaluations were performed using UNIX SAS version 9.01 (SAS Institute Inc, Cary, NC) and Stata 9.0 for Windows (StataCorp LP, College Station, TX). Chi-square and Student t tests were used to compare demographic and clinical characteristics as well as outcome variables between the step-therapy and comparison groups after step therapy had been implemented.
The general model specification was:
Y = g(α0 + β1*Stepit + β2*TimeStepit + β3*Quartert + β4*Quarter2 t + β5*Demit + β6*Clinicalit), where i is person and t is time in quarters.
The explanatory variables were defined as follows: Y: medical care utilization or expenditure measure. Step: a 0/1 dummy variable that equals 1 after the employer instituted step therapy and 0 otherwise. TimeStep: a numeric counter measuring the number of quarters since step therapy began (ie, 1, 2, 3...). Quarter: a time trend variable to capture the linear utilization and spending trends common to both the step-therapy and comparison groups, with the first quarter of 2003 coded as 1 and the third quarter of 2006 coded as 15. Quadratic trends were captured with the Quarter2 variable. Dem: demographic characteristics including age, sex, median income in the patient’s ZIP code of residence, and percentage of college graduates in the patient’s ZIP code of residence (from the US Census). Clinical: clinical characteristics including number of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes in the prior year and Deyo-Charlson Comorbidity Index over the prior year.
Multivariate generalized estimating equation models were used to estimate the effects of step therapy on spending and utilization while controlling for important covariates and adjusting for clustering by patient.6 Utilization variables, representing counts of each type of service, were estimated with a negative binomial distribution and a log link. Discontinuation was estimated by using a binomial distribution and a logit link. Expenditures were estimated by using a gamma distribution with a log link.