Impact of an Educational Intervention for Secondary Prevention of Myocardial Infarction on Medicaid Drug Use and Cost

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The American Journal of Managed Care, July 2004 - Part 2, Volume 10, Issue 7 Pt 2

Objectives: The objectives of this drug utilization review programwere (1) to increase β-blocker prescribing to fee-for-servicepost-acute myocardial infarction (AMI) Medicaid patients; (2) toimprove compliance among patients who were prescribed β-blockers post-AMI; and (3) to evaluate the economic implicationsof increased β-blocker prescribing.

Study Design: Pre-post nonequivalent group design.

Patients and Methods: The intervention targeted physicians ofPennsylvania Medicaid recipients who had an AMI betweenNovember 1, 1998, and November 1, 1999. Educational materialswere sent to the physicians of post-AMI patients not receiving β-blockers. Preintervention and postintervention rates of β-blockerprescribing in the Medicaid program within 7 and 30 days of dischargeafter an AMI hospitalization were compared. Similarly, pre andpostintervention compliance rates were compared for AMIpatients who were prescribed β-blockers. Cost savings and numberof avoided deaths also were calculated.

Results: There was a 5.5% to 6.9% increase in β-blocker prescribingafter the intervention, depending on the follow-up period.Postintervention AMI patients were 16% more likely to beprescribed a β-blocker. There was an 8.3% increase in patientcompliance with β-blocker therapy from preintervention to postintervention.In the first 2 years of the intervention, the estimated costsavings to the Pennsylvania Medicaid program ranged from$71 970 to $76 678, respectively. An estimated 3 deaths wereavoided.

Conclusions: The intervention resulted in increased appropriateprescribing and compliance with β-blockers among post-AMIpatients. There also were estimated cost savings to PennsylvaniaMedicaid as a result of reduced hospitalization, and fewer deaths.

(Am J Manag Care. 2004;10:493-500)

Patients who survive an acute myocardial infarction(AMI) are at an increased risk for suddendeath, nonsudden death, and reinfarction.1 In thepast 2 decades, numerous trials have demonstrated thatβ-blockers can improve survival and reduce the rate ofreinfarction in patients with AMI.2-8 However, publishedreports indicate that β-blockers are underutilized.9-25

Most educational programs targeting hospital physicianshave successfully increased β-blocker prescribingduring hospitalizations for AMI.26-29 These examplesshow that intensive educational programs can influenceprescriber behavior and increase the proportion ofpatients who receive β-blockers after an AMI. However,these interventions were directed at hospital physicians.How these results might apply to a less intensiveeducation program targeting ambulatory care physiciansis unclear.

Once AMI patients are prescribed a β-blocker, therapyshould continue indefinitely, unless a complicationarises. Therefore, compliance becomes an issue. In theBeta-Blocker Heart Attack Trial, investigators foundthat patients who took ≤75% of their prescribed β-blocker regimen were 2.6 times more likely to die withinthe first year of follow-up than more compliantpatients.30 Clinical data relative to long-term use of lifesavingdrugs in 156 survivors of definite myocardialinfarction at a government, university-affiliated teachinghospital were analyzed over a 24-month follow-upperiod. Among post-AMI patients who were dischargedhome with a β-blocker prescription, only 71% remainedon their β-blocker medication at 24 months.31

Among intervention programs to increase the use ofβ-blockers after AMI, economic evaluations have notbeen done to our knowledge. Bradford et al believedthat there are 3 types of costs associated with underutilizationof β-blockers: (1) costs due to higher mortalityor morbidity (reduced health) attributed to suboptimalcare; (2) increased use of medical resources (eg, hospitaladmissions, physicians visits) because of less appropriatetreatment; and (3) costs of less effectivetherapies.32 Due to the paucity of literature on costimplications of β-blockers, Bradford and colleaguescould only calculate the first type of costs: years of lifelost due to underutilization of β-blockers in the UnitedStates and the associated dollar value of the loss.Soumerai et al estimated that β-blockers could reducethe risk of readmission to hospitals for all cardiac eventsby 22%.33 However, the cost consequences of cardiacevents can vary significantly, which hinders the attachmentof a dollar value to the reduction in hospitaladmissions. Goldman et al, in a widely cited article,examined the cost of β-blockers per year of life saved.34Phillips et al used a computer-simulation Markov Modelto estimate that the incremental cost per quality-adjustedlife-year gained would always be less than$11 000.35 However, the cost implications in terms oflife-years saved often are not the primary concern ofintervention programs. On the contrary, the interventionprograms are most interested in the cost savings tothe payers.

The overall goal of this educational intervention programwas to increase the prescribing of β-blockers tofee-for-service Medicaid patients immediately after ahospitalization for AMI. A secondary project aim was toimprove compliance among patients who were prescribedβ-blockers post-AMI, but who were refillingtheir prescriptions at intervals that suggested poor compliance.The third aim was to evaluate the economicimplications of an increase in β-blocker prescribing.

METHODS

Educational materials were produced and distributedspecifically for this project by the Pennsylvania MedicalSociety's Center for Professional Drug Education.Physicians for the intervention were identified based onclaims data. They were put into 1 of 3 groups: (1) thosewith post-AMI patients who were noncompliant with β-blocker therapy; (2) those with post-AMI patients whohad not been prescribed a β-blocker; and (3) all otherphysicians with a specialty identified by the PennsylvaniaMedical Society that had the potential to treat a post-AMIpatient (eg, internal medicine, family medicine).Cardiologists were excluded from the first 2 interventiongroups because it was assumed that most patients werefollowed by their primary care physician after dischargefrom the hospital, and that cardiologists were more likelyto prescribe β-blocker therapy when appropriate.36

In the first group, prescribing physicians were identifiedfor those patients who had 1 or more β-blockerprescriptions, but had β-blocker availability rates below80%. Beta-blocker availability rates were defined as thepercentage of time when β-blockers were available forthe patients after the initiation of β-blocker use post-AMI. It was calculated by dividing the β-blocker availabledays by episode days for all recipients with 1 ormore β-blocker claims after their index AMI hospitalization.Beta-blocker available days were determined bycounting days of drug availability based on the days supplyfrom the dispensing date forward. Episode days werethe number of days from the first β-blocker prescriptionafter the AMI through termination of Medicaid fee-forserviceeligibility, or the end of the study period, ifearlier. Days hospitalized were subtracted from thedenominator and patients with negative β-blocker availabilityrates due to extended hospitalizations wereexcluded. Compliance was defined as having β-blockeravailability rates equal to or above 80%. Patients with β-blocker availability rates below 80% were considerednoncompliant.

Patient drug history profiles were created for thosepatients for whom compliance was an issue. A case-by-casereview of the profiles was conducted to excludefalse-positives, which were patients who were labeled"positive" but who were in fact compliant based onimplicit review by Pennsylvania Medical Society staff.These false-positives were probably due to administrativeor data entry errors. From 309 "positive" patients,135 were excluded.

Counter Details

Two intervention educational packets were developedand administered. One packet was mailed to thephysicians whose patients were identified as noncompliant.The educational materials included an introductionletter, the newsletter, a Medicaidpatient report, a response form, and each patient's drughistory profile.

Counter Details

The introduction letter discussed the review aimsand reported the overall post-AMI β-blocker prescribingand compliance rates in Pennsylvania Medicaid. The newsletter, which offered continuingmedical education credit, included current strategies inthe treatment of myocardial infarction, identified thefactors contributing to compliance problems amongpatients, and laid out actions that physicians need totake to increase patient compliance rates. The Medicaidpatient report listed the physician's noncompliantpatients. In the drug history profiles, β-blocker prescriptionswere grouped separately and listed first. Thephysician response form was included with the educationalmaterials to assess the acceptance of the interventionby the physicians.

Counter Details

Counter Details

The other packet was mailed to physicians whosepatients were identified by the underutilization criterion.These physicians received an introduction letterand the newsletter. If a physician hadpatients who met both criteria, they only received thecompliance educational packet. In total, 328 physiciansreceived "underutilization packages," 157 physiciansreceived "noncompliant packages," and 10 972 physicians(the third group of physicians) received only the newsletter. We were unableto determine what percentage of AMIpatients saw these physicians in the postinterventionperiod.

Counter Details

The timeline of the study was as follows:(1) Physicians were identified fromNovember 1, 1998, through November 31,1999. (2) The intervention packages weremailed to them on April 28, 2000. (3) Twoweeks later a follow-up certified letter wassent to each nonresponder. (4) General mailingof newsletters to physiciansin the third group took place on May 1,2000.

To evaluate the impact of the educationalprogram on the prescribing of β-blockerspost-AMI, we calculated the proportion ofAMI patients with a paid claim for a β-blockerwithin 7 and 30 days of discharge.Medicaid recipients who were hospitalizedfor an AMI between November 1, 1998, andOctober 31, 2001, were identified throughMedicaid inpatient administrative claims.Patients were classified into 1 of 3 periodsbased on the timing of their AMI hospitalizationwith respect to our educational program:preintervention (November 1, 1998, toMarch 31, 2000); during the interventionperiod (April 1, 2000, through May 31,2000); and postintervention (June 1, 2000,through October 31, 2001). Patients wereexcluded if they were less than 21 years old,if they died during the first (index) AMI hospitalization,or if they had no prescriptionclaims during the study period.

To avoid overestimation of β-blocker use,only the first AMI hospitalization within thestudy period was selected. Patients withavailable β-blockers, based on prescriptionhistory immediately before the AMI hospitalization,were counted as receiving β-blockers in both the 7 andthe 30-day analyses. Patients without a pharmacy claim100 days before the index AMI hospitalization wereexcluded from this analysis to limit analysis to thosewith prescription benefits. Because this exclusion hadsuch a large effect on the denominator (almost one halfof the patients were ineligible because they had no priorprescriptions), it would tend to result in overestimationof the percentage of β-blocker use in the population.Because it is applied consistently over each time period,it shouldn't affect the relative difference from 1 periodto the next. Finally, because of missing pharmacy data,patients with fewer than 7 (or 30) days of continuousMedicaid eligibility, or an inpatient or psychiatric hospitalizationduring these postdischarge periods, wereexcluded from the 7-day and/or 30-day utilization calculationsas appropriate.

The economic effects of the intervention programwere evaluated in terms of (1) cost savings to thePennsylvania Medicaid fee-for-service program and (2)number of deaths avoided in the PennsylvaniaMedicaid program. The outcomes of patients who weredischarged from hospitals after AMIs were categorizedas sudden death, nonsudden death, nonfatal reinfarction,and other, as reported in the Figure (probabilitieswere based on the meta-analysis by Yusuf et al8).This figure was generated by using Data, Version 3.5,©No[1988-1998] Treeage Software, Inc,® of Treeage Inc,Williamstown, Massachusetts, USA.37 When estimatedfrom the perspective of the Pennsylvania Medicaid program,the economic effects of the intervention programcould result from the number of nonsudden deaths andnumber of nonfatal reinfarctions avoided. The totalcost savings of the intervention was considered to bethe sum of the reduced hospitalization costs for treatingfewer patients with nonsudden deaths and thereduced costs for treating fewer patients with nonfatalreinfarctions.

The data points were estimated as follows: The ratesof nonsudden deaths for patients who were put on β-blockers (4.1%) and for those who were not (4.6%),within an average follow-up period of approximately 2years, were based on an estimate from the meta-analysisby Yusuf et al.8 From the same meta-analysis, therates of nonfatal reinfarction were estimated to be 5.7%in the β-blocker group and 7.5% in the control groupwithin the same follow-up period.8 The hospitalizationcost of nonsudden AMI-related deaths was estimated tobe $21 679, which was adjusted to 2001 dollars from astudy that reported direct medical costs of treating afatal AMI.38 The hospitalization cost for a patient whosurvived an AMI was estimated to be $19 326, whichwas adjusted to 2001 dollars from a study on the costof ischemic complications.39

In addition to estimating the cost savings to thePennsylvania Medicaid program, we also estimated thetotal number of deaths avoided due to the intervention.The reduction in mortality rates due to increased use ofβ-blockers was based on the meta-analysis by Yusuf etal, which reported that β-blockers could reduce themortality rate from 10.0% to 7.9% in the long term.8 Thetotal number of AMI patients considered (4914) wasbased on the total number of unique patients with AMIhospitalizations after excluding multiple AMIs.Estimations of cost savings and deaths avoided were calculatedfor the actual increases seen in β-blocker use at7 days and 30 days post-AMI.

The retrospective drug utilization review programunder which this study was conducted was reviewedand deemed to be exempt by the institutional reviewboard of the University of Maryland (IRB protocol#0101412).

RESULTS

P

There were 5241 AMI hospitalizations during the 3-year study period. With exclusions for multiple AMIsduring the study period (n = 327), patients with no prescriptionclaims within 100 days before the index AMI(n = 2408), and patients without follow-up time afterdischarge (n = 1002), the project evaluation was basedon the remaining 2543 AMI patients (these categories ofpatients overlapped). As reported in Table 1, the majorityof the patients were classified into the preinterventionor postintervention period based on the timing oftheir AMI hospitalization with respect to our educationalprogram. They were mostly women and more than 50years of age. Comparing the preintervention and postinterventiongroups, there were no statistically significantdifferences in age and sex. However, compared with thepreintervention group, the intervention group has asmaller proportion of patients under age 50 ( < .01).

P

P

In the preintervention period, 46.4% of patients withan AMI hospitalization filled a &#946;-blocker prescriptionwithin 7 days and 61.3% within 30 days of discharge(Table 2). These percentages increased to 49.6% of AMIpatients at 7 days and 64.7% at 30 dayspostintervention. These results translatedto a population-wide 6.9% increase in &#946;-blocker prescribing immediately after anAMI hospitalization (within 7 days of thedischarge). However, these increases werenot statistically significant (&#967;2 = 2.35, =0.13, and &#967;2 = 2.44, = .12, respectively).

Using a multivariate proportional-hazardsmodel to adjust for age group, sex,and race, patients with their first AMI inthe postintervention period were 16%(hazard ratio = 1.16, 95% confidenceinterval = 1.05, 1.29) more likely to beprescribed a &#946;-blocker than AMI patientsbefore the intervention period (Table 3).

P

Based on prescription refill dates, 64.1%of preintervention &#946;-blocker users had &#946;-blockers available 80% or more of the time (Table 4).These patients were considered "compliant with therapy."Compliance increased to 69.4% of &#946;-blocker usersafter the intervention. This represents an 8.3% increasein compliance from preintervention to postinterventionamong &#946;-blocker users in Pennsylvania Medicaid. Thisincrease is statistically significant ( = .02).

The projected cost savings of the intervention programare reported in Table 5. The difference betweenthe total costs before and after intervention was the estimateof cost savings due to the intervention. The costsavings of the intervention program during the first 2years were estimated to be in the range of $71 970 to$76 678.

Based on the changes in &#946;-blocker prescribing fromthe preintervention to the postintervention period andthe reduction in mortality rates reported in the literaturewhen patients are put on &#946;-blockers, we estimatedthat 3 deaths were avoided.

DISCUSSION

The University of Maryland, in conjunctionwith the Pennsylvania Medical Societyand Commonwealth of Pennsylvania'sDepartment of Public Welfare, Office ofMedical Assistance Programs, designed andimplemented a systemwide educational programto increase physician awareness of thecurrent treatment guidelines for AMI survivors.A program goal was to increase prescribingof &#946;-blockers immediately after anAMI hospitalization among Medicaidenrollees. This goal is closely aligned with aHealth Plan Employer Data and Information Set(HEDIS&#174;) measure of health care quality: the proportionof patients prescribed a &#946;-blocker within 7 daysafter an AMI.40 Before the educational program, 46.4% ofeligible enrollees filled a &#946;-blocker prescription within 7days and 61.3% within 30 days of hospital discharge.After the education program, the proportion of AMIpatients on &#946;-blockers increased 6.9% and 5.5% at 7days and 30 days, respectively.

Although these increases appear modest, they applyto all fee-for-service patients with prescription benefits,and thus include a large absolute number (approximately5000) of patients. Furthermore, because theintervention was programwide, materials were disseminatedto most general practitioners in Pennsylvania,and as such, are likely to have some impact on care ofAMI patients well beyond the study population. In addition,due to funding limitations, our educational interventionwas carried out in a simple and low-costmanner relative to more intensive interventions such asacademic detailing. However, our program resulted inan increase in &#946;-blocker use despite the larger geographicarea of our intervention and wider dispersion ofindependent physicians in the ambulatory care settingcompared with interventions in hospital settings.26,27

The second program goal, to improve compliancewith &#946;-blocker therapy among &#946;-blocker users, was reasonablysuccessful. Good compliance was defined ashaving medication available for at least 80% of the daysafter initiation of &#946;-blocker use. We found an 8.3%increase in the proportion of compliant patients after thesystemwide physician education program with a personalizedmailing to physicians of noncomplaint patients.

Applying the increase in &#946;-blocker use at 30 days toall 4914 AMI patients (regardless of prior prescriptionclaims) resulted in an estimated savings of up to $76 678and 3 deaths avoided. Because only nonsudden deathsresult in consumption of healthcare, the analysis on costsavings only included nonsudden deaths. For patientswith nonsudden deaths or nonfatal reinfarction, only hospitalizationcost was included in this analysis becausehospitalization cost is the largest component of resourceuse due to AMI. As such, these estimated cost savingsshould be viewed as a lowerbound. Actual cost savingsmay be greater.

The cost savings due toincreased prescribing of &#946;-blockers do not come as asurprise; &#946;-blockers havebeen established as cost effective for secondary preventionof AMI. In the most widely cited study on thecost effectiveness of &#946;-blockers at discharge forAMI, Goldman et al reporteda cost per year of life saved in the range of $2327 to$13 571 (in 1987 dollars).34 Kuntz and Lee updated theresults by Goldman and estimated a cost per life-yearsaved to be from $3 400 to $19 800.41 Both before andafter being updated, these cost-effectiveness ratios arevery advantageous, because treatments with cost-effectivenessratios in the range of $20 000 to $30 000 per life-yearsaved are generally considered highly costeffective.32

These analyses were limited to Medicaid recipientswho have prescription benefits as determined by aprescription claim before their AMI hospitalization.Because we used prescriptions as a proxy for drugcoverage, approximately one half of the AMI patientswere excluded because they did not have a prescriptionclaim within 100 days of their AMI. This wasdone to avoid underestimating &#946;-blocker use.

There are several factors inherent in the study design,and particularly the use of claims data, that would affectour estimate of the impact of the intervention. One factoris misclassification of persons who did not have anAMI as having an AMI hospitalization. Only records ofpatients with an AMI indicated as a primary diagnosis onthe hospital claim were studied. Because the diagnosis ofAMI was not validated against the medical record, itcould be miscoded, particularly in cases where a suspectedAMI was later ruled out. Also, patients in whom&#946;-blocker therapy is considered optional because theyhad a small myocardial infarction with no evidence ofcontinuing ischemia could not be identified.Furthermore, patients who took home medication fromthe hospital (eg, free samples) may not fill their prescriptionuntil that supply is exhausted. This also wouldcause us to underestimate the number of patients on &#946;-blockers within 7 days, though use of free samples isunlikely to bias the 30-day estimate.

In our analysis, we included all post-AMI patients inthe calculation of &#946;-blocker prescribing, although somepatients might not have been on &#946;-blockers due to contraindications.Determining the medical conditions ofpatients accurately by reviewing medical records wasnot possible with this study.

The evaluation of compliance depends on a numberof assumptions. First, patients' average daily dose had tobe estimated in order to calculate the number of pillsavailable. Although there are typical or standard doses,compliance may be underestimated among patients whosplit pills and overestimated among patients who take anunusually high dose. However, we assumed standarddoses. Additionally, we used drug availability as a proxyfor adherence, assuming patients took the medicationthat was available and did not refill their prescriptionuntil they used all of their available supply. An accuratedetermination of compliance typically requires directobservation of a patient's daily medication-taking behaviorand/or direct assessment of drug levels in the body.

CONCLUSION

The systemwide physician education program inPennsylvania Medicaid program increased &#946;-blockerprescribing after AMI hospitalization by increasingphysicians' awareness of the guidelines for treatment ofAMI survivors. The educational intervention also improvedpatients' compliance with &#946;-blocker therapy.These effects are likely to apply to AMI patients wellbeyond the study population. Besides clinical effects,this intervention program also led to cost savings forthe Pennsylvania Medicaid program, as well as avoidanceof a few deaths.

Acknowledgment

The authors thank Lori Walker, BS, of the School ofPharmacy's Pharmaceutical Research Computing, for her analyticand programming support.

From the Center on Drugs and Public Policy, University of Maryland School ofPharmacy, Baltimore, Md (IHZ, SRW, DM, CDM, JW); and the Center for Professional DrugEducation, Pennsylvania Medical Society, Harrisburg, Pa (BL).

This study was supported by the Commonwealth of Pennsylvania's Department ofPublic Welfare, Office of Medical Assistance Programs.

Address correspondence to: Ilene H. Zuckerman, PharmD, Center on Drugs and PublicPolicy, University of Maryland School of Pharmacy, 515 W Lombard St, 2nd Floor,Baltimore, MD 21201. E-mail: izuckerm@rx.umaryland.edu.

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