Written By :
Miguel Franquiz, PharmD Candidate 2016
Reviewed By :
Livia Macedo, Pharm.D.
Carter VL., et. al. (2009) Physician and Pharmacist Collaboration to Improve Blood Pressure Control. Internal Medicine, 169(21), 1996-2002.
Large epidemiologic studies1,2 have shown that in the United states, a country with a high prevalence of hypertension, often more than half of these patients have uncontrolled disease. Despite national lifestyle modification efforts, a strong focus on public health literacy, and widely disseminated evaluation and treatment guidelines, hypertension control remains suboptimal. The reasons behind such subpar control are no doubt multifactorial, and a great deal of time, effort, and resources have been focused on designing clinical strategies to improve hypertension control. One such modality incorporates team based patient care, involving a physician and a pharmacist working collaboratively. Data from primary literature clearly show significant improvement in blood pressure control following physician-pharmacist comanagement interventions.3,4,5 In an attempt to validate such findings, Carter et. al. have conducted a large, multi-center trial evaluating outcomes of physician-pharmacist comanagement of hypertension in community healthcare settings.
Physician and Pharmacist Collaboration to Improve Blood Pressure Control (PPC-BP) was a prospective, randomized , multi-center, open-label, parallel assignment, controlled trial with the goal of demonstrating improved efficacy of physician and pharmacist comanagement of hypertension over usual care.6 The primary outcome was physician adherence to hypertension guidelines, measured by a computer algorithm previously developed by the investigators7. The secondary outcomes were blood pressure control quantified by surrogate markers, physician knowledge, physician-pharmacist relationship, and patient medication adherence. The trial enrolled 623 participants and was designed with 88-100% power to detect a statistically significant difference in systolic blood pressure between treatment and control groups. All outcomes were assessed during two 6-month periods: prior to the patient’s enrollment in the trial and again while the patient was enrolled in the study.
The study included males and females older than 21 with diagnosed essential hypertension with systolic blood pressures between 140 and 179 for non-diabetes patients, and systolic blood pressures between 130 and 179 for patients with a history of diabetes. Eligible participants were randomized to one of 6 different investigation sites located in community medicine offices. Physician and pharmacist collaborative care was employed at three sites, and standard treatment at the other three. The three intervention sites also contained passive observation populations, usual care groups that served to analyze covariance within a particular investigation site. Physicians and pharmacists at all sites underwent team building sessions and guideline adherence education prior to study interventions. Specific intervention strategies were structured and presented to physicians and pharmacists at the 3 intervention sites, but implementation was dictated by the investigators. Interventions included collaborative physician and pharmacist in-office patient visits, medication regimen reviews and reconciliation, and a 1 month follow up telephone interview completed by the pharmacist to stress medication adherence. In the usual care group, pharmacists present at community medicine offices were available to provide drug information to physicians and performed duties not above their normal employment at the office.
Guideline adherence improved dramatically in the experimental group as compared to usual care (8.4% vs. 55.1% from baseline). Guideline adherence was not assessed for the passive observation group. Mean reduction in systolic blood pressure from baseline was also superior in the intervention group (20.7 mmHg vs. 6.8 mmHg). Systolic blood pressure reduction in the passive observation group was comparable to the active control group but was not assessed statistically per measurement reliability (trained research nurse vs. retrospective medical record audit).
Based on these results it would it appear that the improvements in hypertension control brought about by pharmacist and physician collaboration are certain, and objectively verifiable. The benefits of systolic blood pressure reduction with respect to actual clinical outcomes have been demonstrated in numerous other publications8,9. However positive this study’s results, they do carry the potential to mislead audiences, stemming from flaws in study design and implementation. First, the positive results in this study may not necessarily translate to other primary care demographics. This study assessed mostly white male participants and was skewed towards an age range of 57-63. The study population also showed little evidence of chronic hypertensive disease or end toxicities of others chronic diseases (CVA, MI, Angina, cardiovascular surgery, LVH, HF). In addition, although this study far surpasses its peers in terms of numbers of participants, larger studies are necessary to establish strong statistical support of the documented benefits. Another disadvantage of this study stems from its heterogeneity in intervention implementation. Although the authors note that physicians and pharmacists attended team building and guideline education sessions, they opted to allow individual investigators to control how the intervention was implemented at their respective sites. This introduces an element of uncertainty to the findings, and without clearly defined, uniform interventions across sites, it’s possible that this same study design may not reproduce similar results if repeated. Lastly, as the study only reports 6 month outcomes, it’s hard to say whether or not such great benefit is sustainable.
When viewing this trial in context of the litany of other publications objectively demonstrating similar improvement in hypertension control, I believe that physician-pharmacist collaboration represents a clearly effective strategy in combating the drastically high prevalence of uncontrolled hypertension in the United States. Whether such poor control is attributable to life style, clinical inertia, or any other of the many competing theories, it would seem prudent that we begin to shift our attention toward solutions. Although there are many barriers to effective collaboration in healthcare, our great focus on evidence based practice favors collaboration in the case of this poorly controlled chronic disease.
1. Keenan NL., Rosendorf KA (2011). Prevalence of hypertension and controlled hypertension-United States, 2005-2008. CDC MMWR 2011, 60, 94-97.
2. Burt VL., Whelton P., Roccella EJ., et. al. (1995). Prevalence of hypertension in the US adult population results from the Third National Health and Nutrition Examination Survey, 1988-1991. Hypertension, 25(3), 305-313.
3. Weber CA., Ernst ME., Sezate GS., et. al. (2010). Pharmacist-physician comanagement of hypertension and reduction in 24-hour ambulatory blood pressures. Archives of internal medicine, 170(18), 1634
4. Tobari H., Arimoto T., Shimojo N., et. al. (2010). Physician–Pharmacist Cooperation Program for Blood Pressure Control in Patients With Hypertension: A Randomized-Controlled Trial.American Journal of Hypertension, 23(10), 1144-1152.
5. Carter BL., Doucette WR., Franciscus CL., et. al. (2010). Deterioration of Blood Pressure Control After Discontinuation of a Physician‐Pharmacist Collaborative Intervention.Pharmacotherapy: The Journal of Human Pharmacology and Drug Therapy,30(3), 228-235.
6. Carter VL., et. al. (2009) Physician and Pharmacist Collaboration to Improve Blood Pressure Control. Internal Medicine, 169(21), 1996-2002.
7. Milchak JL., Carter BL., Ardery G., et.al. (2006). Development of explicit criteria to measure adherence to hypertension guidelines. J Hum Hypertens. 20(6), 426-433.
8. Whelton PK., et al. (2002) Primary prevention of hypertension. JAMA: the journal of the American Medical Association 288.15,1882-1888.
9. Guilbert JJ. (2003) The world health report 2002-reducing risks, promoting healthy life. Education For Health. 16.2, 230-230.