What is the best measure of medication adherence?

Over the last year, one of the most common questions I have received is how to best measure medication compliance or adherence for routine program reporting.  Given the slowed growth in utilization and the need to differentiate, it seems that most PBMs and health plans have placed a renewed emphasis on improving medication adherence.  

While medication possession ratios (MPRs) or versions of MPR tend to dominate the reporting tools, MPR is not, in fact, the best measure of medication adherence.  Why?  The results of an MPR analysis depend heavily upon the methodological choices made in defining MPR and the quality of the days supply figured provided by the pharmacist; and MPRs allow for little clinical interpretation.  Each of these issues is discussed briefly below.

Methodological Choices 

  • First as background, MPR is calculated as the sum of the days supply for all claims during a defined period of time divided by the number of days elapsed during the period.  MPRs can change significantly based on how the denominator is calculated.  In a previously published example in JMCP, a patient’s MPR when the denominator was based on the time between the first and last fill was 0.75; but when the denominator was the entire time period, the MPR was only 0.53.  Reason being, in the first approach, the MPR is affected solely by gaps between fills. When the entire calendar period is used, the MPR is affected both by gaps and treatment discontinuation.
  • MPRs defined over longer time frames using fixed time periods will, by definition, be lower due to decreases in persistency over time so you cannot do a head-to-head comparison of a vendor who reports MPRs on quarterly basis to another vendor who reports MPR on an annual basis.   
  • Third, MPRs are highly sensitive to the population included.  If the report includes both new and ongoing users, an influx of new patients into the program will artificially lower the MPR when it is based on a fixed time period as the denominator.  Reason being, new users have lower persistency rates than ongoing users. 


Quality of days supply

MPRs rely on the accuracy of the days supply figure provided by the pharmacist.  In the case of inhalers, injectables and liquids, these figures are notoriously unreliable so the reporting of an MPR is simply not appropriate for many medications.  For oral pills, the problem is less significant but comes into play when different drugs dosages have price parity and/or pill-splitting is common.

Little clinical interpretation

The most significant limitation of the MPR is the lack of ability to assess the clinical meaning of an observed improvement.  When programs claim to improve MPR by 3-5 percentage points, it is simply unknown what clinical impact, if any, will be seen from this increase in MPR.  Research examining the relationship between changes in compliance and clinical outcomes, is sorely lacking.  While researchers have historically used an MPR of 80% or better as the benchmark for good adherence, it is well-known that this is a somewhat arbitrary cut-off, driven more by precedence than clinical rationale.

Is there a better alternative to MPR?  Yes, and I’ll share some thoughts on this alternative later this week.


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Tis The Season for Drug Trend Reports

The concept behind drug trend reports, now standard fare in the PBM industry, was pioneered by Barrett Toan, former CEO of Express Scripts.  Toan believed that the old adage–” you cannot manage what you cannot measure”– applied to pharmacy benefit management.  While common knowledge today, at the time, the industry did not understand the basics of how price, utilization, and drug mix contributed to drug trend overall, let alone by therapy class.  Hence, the Drug Trend Report (DTR) was born.  First published in 1997, the DTR has contributed greatly to the market’s understanding of drivers of drug trend and how to better manage wasteful drug expenditures.  The value was seen immediately in the marketplace, as evidenced by the press coverage, the use by policymakers in D.C., and how quickly the other major PBMs followed suit.

Now that drug trend season is upon us, it is a good time to discuss appropriate and potentially inappropriate uses of these reports.  In recent years, some organizations have attempted to use book of business drug trends as evidence of PBM effectiveness in managing drug trend.  Such comparisons are simply not valid for couple of reasons.  First, the magnitude of drug trend across PBMs tend to be more similar than different in any given year; and as the figure below shows, underlying market trends (e.g., new product launches, generic availability) are, by far, the strongest driver of trends from one year to the next.  Second, varying methodologies and client mix (e.g., health plan vs. employer, age) in any given year significantly impact drug trend, making direct comparisons highly problematic.

Prescription Drug Trend: 1996 to 2008

The second area of potential misinterpretation relates to meaning of the drug trend number.  As drug trends have slowed in recent years to single digits, plan sponsors have certainly felt some reprieve.  However, this sense of relief can become problematic when a reduction in drug trend is confused with or viewed to be the same as a reduction in drug spend.  Reason being, drug trend only examines the change in drug spend over time and provides no assessment of the appropriateness of the underlying drug spend.

Accordingly, a review of actual drug spend can paint a very different picture of current pharmacy benefit performance than does single digit drug trend. Anticonvulsants are a classic case in point.  Drug trend fell nearly 30% in 2009 due to the availability of generics, but prevalence of use grew nearly 5%.  Of course, the challenge is that much of the growing use in this class represents off-label use that is not scientifically supported, exceeding 70% in most studies.

Keeping these two caveats in mind, Drug Trend Reports are a useful reference tool in understanding the complexities of prescription trend drivers and cost management tools.

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Study Shows Slight Preference Advantage for Community Pharmacy Over Mail Pharmacy

I finally had a chance to read the study on mail and community pharmacy preferences published in The Journal of the American Pharmaceutical Association, an article which has been the focus of much discussion over the last several weeks.  The study, published by CVS Caremark, examined member’s choice of channel in the first 4 months after being converted from an incentivized or mandatory mail program to their Maintenance Choice program, which offers an equal financial incentive for mail and 90-day retail.

The study was well-done methodologically and the conclusions did not over-interpret the data.  What has been surprising to me is that the study is being discussed by some stakeholders as evidence that members, when equally incentivized, will choose mail over community pharmacy.  This conclusion is not supported by the study, was not a conclusion made by the authors, and in fact, a detailed review of the study suggests the opposite conclusion.

The basis for this inference seems to be the finding that 56% of patients who were new to therapy (i.e., had never filled that particular medication at either a mail or community pharmacy) chose mail service for their prescription, a slight majority.  However, if you read the study details, 76% of those patients had previously used mail for OTHER medications.  Accordingly, when results are examined by whether or not the member had previously used mail for any medication, only 32% of patients with NO prior mail use chose mail for the new prescription and 63% of those with prior mail use chose mail for their new prescription.  In other words, community pharmacy was the preferred choice for the majority of patients who had not previously used mail for any prescriptions.

The data for ongoing users can be broken down the same way, showing that 21% of patients with NO prior mail use chose mail for their refill and 75% of those with any prior mail use chose mail for their refill.  Again, when you examine data points for both new and ongoing users, community pharmacy appears to have a slight advantage in terms of percent choosing.  Furthermore, the authors note that the most important predictor of selecting mail service pharmacy was recent use of mail for another medication.  Specifically, the odds ratio for selecting community pharmacy was 3.77 for community pharmacy users compared to prior mail users.

Also note that this study did not examine whether the members’ spouse had previously used mail, which I have found in previous research to be a strong predictor of mail use.  Reason being, much of the initial paperwork is already in place and there is a familiarity with the mail service, reducing the barriers to use.  Inclusion of this covariate would likely increase the odds ratio for prior mail use.

All that said, the authors conclusion, which focused on the diversity of preferences rather than which channel had an inherent preference advantage, was on point—“Patient behavior indicates that certain patients prefer to access prescription medications via mail service and others through community pharmacy.”  Bottom line: if your PBM offers competitive 90-day retail rates, take advantage of them, with the caveat that you will need to make sure that your formulary and generic promotion programs remain effectively in place.

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JMCP Publishes Editorial on VBID: What Do We Really Know?

Published today in the Journal of Managed Care Pharmacy (JMCP) is an editorial on value-based insurance design, written by Kathleen Fairman and Fred Curtiss.  In the article titled “What Do We Really Know About VBID? Quality of the Evidence and Ethical Considerations for Health Plan Sponsors”, Fairman and Curtiss review the recently published studies of copay waivers and discusses the implications for payers, both private and public.

 The paper notes that use of copay waivers is estimated at about 20% of plan sponsors, but plan deductibles are actually trending higher, not lower.  While the reasons for the still minority uptake have not been formally studied, the authors point to market data suggesting the “potential for short-term increases in utilization and cost” with “uncertain” health benefits and the possibility of “unintended incentives” that could reduce generic drug utilization if brand drug copayments are reduced too much.

The editorial also provides an extensive review of the challenges associated with defining low-value services, which under the original intent of value-based benefits, are those for which copays should be raised, rather than lowered.

In their review of the recent literature, the authors discuss five major weaknesses of the studies published to date, including:

  • No information about generic utilization (the concern being that copay waivers for brands may discourage use of lower cost, clinically appropriate generic alternatives)
  • No information about payer cost, despite claiming a positive ROI from copay waivers in some recent studies
  • Problems in study design and/or reporting (e.g., inability to control for the Healthy Adherer effect)
  • Lack of randomized trials
  • Lack of plausibility in cost-benefit analysis (e.g.,  a VBID copayment reduction would have to increase the effectiveness of statin treatment by approximately 41%-49% in secondary prevention  and 68%-79% in primary prevention—despite increasing medication adherence by only about 4%-6%, a clear implausibility.)

For future research, the authors warn plan sponsors to watch out for: 1) isolated significant findings; 2) causal linkages (or lack thereof); 3) reporting of total cost rather than health plan or sponsor cost; and 4) overextension of results from one study to other populations and benefit designs.

Fairman and Curtiss conclude that “Because VBID has been associated with only minimal medication adherence increases documented only in observational research, and because no health or medical utilization outcomes (e.g., ER or hospital use) have yet been reported for VBID programs, the evidence is insufficient to support expanding its use at the present time.”

VBID is a topic that I have written about extensively, both in the blog and in the published literature, and I found this review both thorough and insightful.  For those of you trying to keep pace with the research in this space as well as the ongoing ethical and practical challenges associated with VBID, this paper is a great resource.

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The Evidence Base for Step Therapy for Pharmaceuticals

While step therapy has been around for a decade or more, it still represents one of the lowest hanging fruit for plan sponsors who want to improve the value received from their pharmacy benefit with minimal member disruption.  Today more than 50 therapy classes have the opportunity for step therapy, including several specialty medication classes.

When I recently returned to pharmaceutical policy work, I was surprised to see how few evaluations of step therapy had been conducted in the last decade, particularly considering step therapy’s high degree of popularity among plan sponsors in both private and public settings.  I was also surprised to see that most of the evaluations of step therapy that had actually examined clinical and economic outcomes were funded by pharmaceutical manufacturers rather than managed care organizations that can provide thought leadership on this benefit tool.

In a paper published today in the Journal of Managed Care Pharmacy , I review the literature on step therapy and highlight important areas for future research.  Clearly, evaluations of step therapy are needed for numerous therapy classes of clinical significance, such as statins and specialty medications.  This is important because one would fully expect patient response and the clinical implications of patient choices to vary by therapy class and by the underlying indication.  The lack of evaluations of step therapy in the Medicare Part D population is a particularly notable gap.

Most of the research to date has focused on the drug cost savings of step therapy, a necessary condition for step therapy’s uptake but certainly not the only outcome of interest.  While savings from step therapy are widely known within healthcare organizations, a better understanding the clinical profile of patients who receive prior authorization for brand medications or receive no medication following a step edit is an important area of inquiry as it has the potential to affect not only economic outcomes, but clinical outcomes and member satisfaction. Perhaps the second most notable gap is the lack of evaluation of alternative forms that are growing in popularity, such as removal of grandfathering and integration of medical claims into the real-time step edits.

 In the paper, I also discuss some of the key methodological concerns with the publications to date and highlight examples of potential bias.  Based on this review, here are a few methodological tactics you should watch for when considering step therapy evaluations:

  • Reporting of non-significant findings as if they were statistically significant
  • Evaluation of all-cause medical expenses rather than disease-related expenses (all-cause medical costs are highly variable are have a greater chance of showing random differences across groups for reasons that have nothing to do with the program being evaluated)
  • Inclusion of patients who were unaffected by the program to calculate drug savings, which will reduce the magnitude of apparent savings
  • Examination of a small subpopulation of patients affected with extrapolations to the entire program

 As I point out in the paper, the popularity of step therapy among commercial, Medicaid, and Medicare plans is no doubt due to the wide availability of generic alternatives that offer significant savings, the strong clinical evidence that typically underlies these programs, and their ability to affect only new users, thereby minimizing member disruption. It is important that evaluations of step therapy keep pace with their growing use in order to optimize program design and patient outcomes.

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Can You Reduce Risk Through Outcomes-Based Contracting for Pharmaceuticals?

I recently attended the Pharmacy Benefit Management Institute’s (PBMI) Annual Drug Benefit Conference where one of the keynote speakers, Ed Schoonveld of ZS Associates, shared his point of view on the merits of outcomes-based contracting.  As you can read in his 2010 article on the subject, Ed advocates to pharmaceutical manufacturers for judicious use of these contracts given their potential complexity and potential risk for being nothing more than a thinly veiled price reduction. 

While I found his article and presentation insightfuI, I was struck by Ed’s comment questioning the wisdom of pharmaceutical companies providing insurance to insurance companies via outcomes-based contracts.   From a literal perspective, a large percentage of employers purchase pharmacy benefits on a self-insured basis through their health plan or PBM so the organization bearing the risk for the pharmaceuticals is often the employer and not an insurance company.  Second, while the price paid to the manufacturer is certain, the uncertainty and accordingly, risks to the employer and health plan are many, including:    

  • Uncertainty about effectiveness under real-world conditions of use that often lacks close monitoring and quick dose adjustment;
  • Uncertainty about the nature and extent of side effects in the broader population and over the long-term;
  • Uncertainty about the extent of use for off-label conditions lacking scientific support;
  • Uncertainty about the extent to which the new product will replace older, equally efficacious alternatives
  • Unknown medication compliance rates under real-world conditions; and
  • Ultimately, unknown cost-effectiveness in the real-world.

There is no shortage of examples of the impact that this uncertainty can have on clinical and economic outcomes for patients and payers; and while employers can mitigate some of these risks through benefit design choices, most are beyond their control.   Certainly outcomes-based contracts can be messy.  However,  the much higher unit cost of specialty medications and even greater uncertainty on these various dimensions relative to traditional medications makes outcomes-based contracting a logical alternative for sophisticated plan sponsors who want to mitigate uncertainty.

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Two Things You Must Know About Employee Wellness Incentive Programs

A new survey, by Fidelity Investments and the National Business Group on Health, reported that the use of employee incentives to promote health and wellness continues to rise.  The Fidelity survey covered 147 companies with between 1,000 and 100,000 employees. The average employee incentive rose 65% to $430 last year from $260 in 2009.

While incentives can be used in all sorts of way, one of the most common uses is for promoting completion of a health-risk assessment (HRA), the idea being that employers can then identify patients who are at highest risk for poor clinical outcomes and target these patients for enrollment in targeted wellness and disease management programs. 

When I first joined the care management industry and began to study evaluate wellness programs, I had two fundamental questions: 1) what is the validity of the self-report HRAs that are so common in the industry and 2) how well do incentives improve participation and  longer-term behavior change?  Here is what we found:

  1. Using self-reported health-risk assessments to identify high-risk patients will miss 90% of your high-risk population.

We examined more than a dozen employers who had simultaneously incentivized completion of a self-report HRA and biometric screening..  Participation was between 70 and 80% across employers, providing an ideal scenario for assessing the validity of the self-reported HRA.  Examining more than 5,000 patients, we found that the percent of members failing to report or under-reporting their risks at baseline ranged from about 20% to more than 60%, depending on the particular measure, as shown below.  An example of under-reporting would be when a member reports that their total cholesterol is 180 md/dl (low risk), but the biometric test finds that the actual score is 250 (high risk).

Percent of Members Failing to Report or Under-Reporting Their Risk


For individual patients, the underreporting was not limited to just one risk factor.  Nearly 50% of respondents failed to report or underreported 3 or more risk factors.  The reasons for underreporting are multiple, likely reflecting a lack of prior testing, lack of memory, or confusion about different biometric scores.  Of course, some of the gap also reflects an unwillingness to share health-related data with their employer due to confidentiality concerns, embarrassment, questions about the program’s value, etc.  Regardless of the reason, the impact of the poor quality data on an employer’s ability to identify high-risk patients was profound– Across these employers, the biometric scores identified 18 percent of the responders as being high risk where the self-report HRA identified only 1 percent of responders as high-risk.  In other words, the self-report missed more than 90% of the high-risk patients.

Improving the quality/validity of responses to self-reported HRAs is no small task given the complex nature of the problem.  However, the alternative of incentivizing biometric scores, while increasingly popular, raises fundamental questions about the employer’s role in promoting wellness. 

A second note of caution relates to the effectiveness of incentives.

                2. Incentives can increase enrollment in a wellness program, but their ability to impact longer-term behavior change and ultimately, outcomes has yet to be seen.

Incentives can be quite effective in promoting completion of an HRA, enrollment in an online wellness program, or other programs that represent a low “cost” to the patient if they enroll.  However, incentives for participation have yet to be shown to lead to longer-term behavior change in employer-based wellness programs.  Perhaps more concerning, there is a notable lack of research which demonstrates that incentives paid for health improvement are effective.  This is not particularly surprising as we know the non-adherence to healthy behaviors (e.g., medication compliance) is a multi-factorial problem in which financials play only a small, if any role, for the majority of employees.

As evidenced by this recent survey, employers are spending a growing amount of money on employee incentives, perhaps with an over-confidence in the effectiveness of these programs given the research to date.  Furthermore, as many companies will inevitably pass on the cost of these incentives to workers in the form of higher premiums, the importance of prudent purchasing becomes even more critical.


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