Business of Well-being

Medication Adherence: Onsite Health Center Analysis

Since the earliest days of medicine, the extent to which patients abide by their providers' medication orders has been an important component of healthcare.  This concept is commonly described as Medication Adherence.  Poor medication adherence not only affects patients, but the entire healthcare system.  

Non-adherent patients are more likely to experience worse outcomes, including early death, than those who are adherent to their medication regimens.5-7 Moreover, studies have reported that 33 percent to 69 percent of hospital admissions in the United States are due to non-adherence, resulting in approximately $100 billion in excess costs.1  

Initiatives that improve medication adherence have demonstrated substantial cost savings, especially through reduced hospitalization and emergency department use.8 Employers that offer onsite health centers with onsite pharmacies to their employees may eliminate barriers to non-adherence.  Some onsite health centers have evolved into a source of sophisticated and comprehensive healthcare for employees.9,10

Many onsite health centers encourage providers and patients to build a relationship to discuss health issues.  Frequently, onsite health centers can provide longer patient visits and shorter waits for appointments.10 Similarly, through their location at the worksite or close by and usual lower copayments and/or discounted prescriptions, onsite health centers facilitate employees' access to care and frequent follow-up.  

Consequently, medication adherence may be improved through convenient, holistic and relatively inexpensive care. Cerner Corporation established the Healthe Clinic in 2006 to provide a range of worksite healthcare benefits. All Cerner associates and their dependents in the Kansas City area are eligible for the clinic's services, which include primary medical care, physical therapy, chiropractic treatments and health coaching.  

In addition, an onsite pharmacy is available within the clinic to provide patients with a convenient economical option for filling prescriptions, along with patient counseling and education.  Lastly, Cerner offers a condition management program for all members and dependents with a diagnosis of diabetes, hypertension and/or body mass index of greater than 35.  

These programs provide personal support, educational materials and other tools provided by a multi-disciplinary team, which includes a health coach, dietician and fitness specialist.


The objective of this study was to analyze Cerner's Healthe Clinic data and assess the medication adherence rates among patients who use the health center and obtain their medications from the onsite pharmacy compared with those who use offsite sources. We performed an analysis of claims data collected for Cerner employees and their dependents enrolled in the company's healthcare benefit program.

Essentially, for this study, the MPR represents the number of days with supplied medication over a period of 365 days.  Switching between medications within the same drug class did not constitute non-adherence. Sub-analyses of MPR data were also conducted.  First, a longitudinal analysis was conducted to assess the change in medication adherence over time.  

Specifically, patients with an index prescription fill during the first 6 months of the intake period (ie, January 2009 until June 2009) were assessed separately during the subsequent 6-month periods.  Second, a comparison of medication adherence among patients enrolled and not enrolled in condition management programs was performed.

Cerner associates and their dependents that were continuously enrolled in the health plan for the duration of the study period were eligible for inclusion.  Patients who filled a target medication during the intake period, January 1st, 2009 until December 31st, 2009, were followed for 365 days following the prescription fill. In addition, patients were required to fill a medication associated with treatment of asthma, depression, diabetes, hypertension or hyperlipidemia.  

These conditions received particular attention because they are the most commonly treated conditions at the onsite health center and chronic illnesses that require prescription refills.  To reduce potential confounders, the following patients were excluded:  those with temporary diagnoses (eg, gestational diabetes); those who switched between the onsite pharmacy and an alternate prescription source; and those aged younger than 18 years treated with medications usually prescribed for depression, hypertension or hyperlipidemia.

Descriptive analyses were conducted to examine the potential medication adherence difference between patients who received medications from the onsite health center's pharmacy and those that used an alternative source for prescriptions. Validation checks of the data were run, and data that appeared missing or incorrect were excluded from analysis.


In total, 2,446 patients were included in the primary analysis.  Of the medication types studied, those associated with depression had the largest sample, with approximately 30 percent of the study population receiving a prescription for one of these agents.  The average MPR among patients who used the onsite pharmacy was higher than that among patients who used another source for their medications: 54.8 percent and 50.7 percent, respectively.  

This trend persisted for the breakdown of MPR by condition for most medication types.  MPR among patients treated with hypertension medications was significantly higher (P = 0.002) for those using the onsite pharmacy (63.0 percent) compared with those using an offsite source (57.1 percent).  Similarly, higher MPRs were observed for onsite pharmacy patients treated with medications for hyperlipidemia (3.7 percent difference), diabetes (2.3 percent difference) and depression (2.2 percent difference), although none of these were considered to be significant (all P = 0.05).

For the longitudinal analysis of MPR for a subset of patients enrolled during the first 6 months, across groups and condition types, medication adherence remained relatively consistent throughout the year.  Significant differences (P = 0.006) among groups were found only among patients treated with hyperlipidemia medications.  

Among hyperlipidemia patients who used an offsite pharmacy, MPR dropped from an average of 85.1 percent in the first 6 months to 75.5 percent in the last follow-up period.  In contrast, MPR remained relatively stable among hyperlipidemia patients who used the onsite pharmacy (80.3 percent to 78.5 percent). Compared with patients who were not enrolled in condition management programs, condition management participants exhibited significantly higher rates of medication adherence for most conditions.  

Specifically, MPR was approximately 25 percent higher among condition management patients.  By condition, this difference was greatest among patients treated with medications for diabetes (27 percent; P < 0.0001), followed by depression (22 percent; P = 0.001), hypertension (20 percent; P < 0.0001) and hyperlipidemia (13 percent; P = 0.005).  Only 3 patients with asthma were enrolled in condition management programs, preventing an analysis of this subpopulation.


Many of this study's limitations affect both onsite and offsite patients, so it is still possible to infer relative differences between the groups.  For example, the study did not account for patients who stopped their medications because they got better.  It is assumed, however, that a similar number of onsite and offsite patients discontinued for this reason.

Nonetheless, the results may be limited by underlying behavioral or demographic differences between onsite and offsite patients.  That is, patients with certain healthcare needs, motivations or knowledge may have been more likely to seek treatment at the onsite health center.


The results of this study provide some evidence that onsite health centers with onsite pharmacies improve medication adherence.  In particular, the MPR analysis demonstrated higher adherence among patients who used the health center's onsite pharmacy than those who used an offsite pharmacy, especially among patients treated with hypertension medications.  

These findings support the hypothesis that onsite health centers promote medication adherence through convenient and quality care. Based on literature reviewed, only one other publication assessed medication adherence in an occupational setting.  This study, conducted by Sherman and colleagues (2009), evaluated MPR among patients who used a workplace health center compared with those who did not have access to such a clinic.14  

The MPR of patients who used the worksite health centers was 80.4 percent, compared with 73.4 percent among those who relied on alternative sources (P < 0.0001).  Although the reported MPRs are higher than those found in the current study, direct comparison is challenging because the inclusion/exclusion criteria varied between the studies.  

Additionally, Sherman and colleagues did not assess adherence for medication associated with the treatment of asthma, depression and hyperlipidemia, which are conditions that typically have lower compliance rates.3 Compared with the current study, the relative differences between onsite and offsite groups were similar to those reported in the Sherman study (i.e. 4 percent and 7 percent).

The sub-analysis of patients enrolled in condition management programs indicates that these initiatives improve medication adherence.  Specifically, the MPR among condition management patients was statistically higher (P = 0.005) for all assessable treatment groups compared to those not in these programs.  Additionally, the MPR was highest among patients with hypertension and diabetes, which are addressed by specific condition management programs offered by Cerner.  

Condition management programs may improve medication adherence by providing an opportunity for providers to counsel patients more frequently, thereby reducing compliance challenges. Despite its limitations, the findings of this study suggest that onsite health centers with onsite pharmacies reduce barriers to medication adherence.  As evidenced by the MPR trends, patients who used the onsite pharmacy, especially those participating in condition management programs, had better adherence than those who did not.  

Likewise, over the course of follow-up, MPR remained relatively stable for patients using the onsite clinic and/or pharmacy, but dropped for many patients who used alternative sources for care. Given the potential of onsite health centers to improve health outcomes and save costs through quality and cost-effective care, additional research should further assess how they can influence and improve medication adherence and methods of improving both compliance and persistence.


  1. Osterberg L, Blaschke T. Adherence to medication. N Engl J Med 2005; 353(5):487-497
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  4. National Council on Patient Information and Education. Enhancing Prescription Medicine Adherence: A National Action Plan.  Available at: Last updated August, 2007. Accessed March 2, 2011.
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About The Authors

Kimberly A. Boaz, PharmD is pharmacist at Cerner Healthe Clinic.  She holds a Doctor of Pharmacy degree from the University of Kansas and completed a community care residency at The Ohio State University.  Her practice interests include medication therapy management, diabetes, hyperlipidemia, and hypertension.  Kim is an active member of the American Pharmacists Association.

Ross M. Miller, MD, MPH is currently a Cerner Medical Executive and functions as national Medical Director for Cerner's employer-sponsored primary and urgent care and occupational health centers. He provides oversight of all medical and pharmacy clinical services and operations, wellness programs, chronic condition management, and benefits administration.

Ron Wade, RPh, MS is a healthcare executive and principal investigator with Cerner LifeSciences, leading project teams in health economic and outcomes research. He has 30 years' experience in pharmacy practice, the pharmaceutical industry, and HEOR research; with over 30 research publications and scientific congress presentations.  A clinical pharmacist, he received his BS and MS degrees from the University of the Pacific in California.

Ms. Kathleen Gorman is a scientist with Cerner LifeSciences consulting and has been involved with a variety of projects that promote best practices and evidence-based medicine.   In particular, she has been increasingly focused on applying research methodology to help conclusively demonstrate the value of onsite health centers and other employer-sponsored wellness initiatives. Prior to joining Cerner she was a researcher at The Parkinson's Institute, a nonprofit organization dedicated to the cure and treatment of movement disorders.  Ms. Gorman holds a BS from the University of California, Santa Cruz and an MPH from the University of California, Los Angeles.  

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