The James A Vohs Award
Summer 1999 / Vol 3, No 2
Clinical Pharmacy Anticoagulation Service. Colorado Region | to pdf >>
The commonly prescribed anticoagulant warfarin requires meticulous laboratory monitoring and follow-up and is the drug most frequently associated with drug-induced hospitalization. The Clinical Pharmacy Anticoagulation Service (CPAS), originated in 1991 with the objectives of assisting physicians and patients in the systematic management of anticoagulation therapy, shifts most anticoagulation therapy management to a clinical pharmacist. In addition to warfarin management, later additions to CPAS included low molecular weight heparin therapy for deep venous thrombosis. The system, one of the largest in the US, manages over 4200 anticoagulated persons with daily 24-hour availability. Analysis of data regarding thromboembolism and bleeding episodes related to warfarin before and after CPAS showed substantial benefits. For example, 1) the percentage of patients with INR values > 6 who developed major bleeding decreased from 6.31% to 1.19%/year (relative risk reduction = 82%; 95% confidence interval 47% to 94%), 2) the risk of hospitalization for a complication of anticoagulation therapy was reduced by 30%, and 3) there was a 77% reduction in the risk of death attributable to complications/failure of anticoagulation medications. After CPAS, the annual rate of major thromboembolism was 2.5%/patient-year, compared with a reported global average of 4.1%/patient-year. The use of low molecular weight heparin therapy for deep venous thrombosis resulted in substantial reductions in number and costs of hospitalizations. In conclusion, the CPAS has improved the quality of anticoagulation therapy by reducing rates of major bleeding, thromboembolism, hospitalization, and death.
The Clinical Pharmacy Anticoagulation Service (CPAS) project was initiated in the Rocky Mountain Division, Denver/Boulder Colorado Local Market in November, 1996. Team member names/titles are provided in Table 1.
The anticoagulant warfarin is among the most commonly prescribed medications in the US. Warfarin is distinguished by being the drug with greatest potential for clinically significant drug interactions and is the agent most frequently associated with drug-induced hospitalization (secondary to bleeding or clotting complications). The difference between an effective dose and a dangerous dose of warfarin is small. Consequently, patients receiving warfarin therapy require meticulous laboratory monitoring and follow-up to assure compliance, and detect bleeding episodes so as to minimize potential for an unfavorable outcome. A patient's response to warfarin therapy is monitored by using the international normalized ratio (INR), a measure of how long it takes the patient's blood to clot.
Our Clinical Pharmacy Anticoagulation Service (CPAS) originated in 1991, when a model for anticoagulation therapy management by clinical pharmacists was developed by a clinical pharmacy specialist at our Westminster Medical Office. This model shifts the majority of anticoagulation therapy management to a clinical pharmacist working in partnership with the physician and within written guidelines. All related activities and outcomes are documented in a comprehensive computerized patient profile and monitoring system. Subsequent internal medicine quality improvement audits and the results of a retrospective outcomes analysis (see Publications) showed improved anticoagulation management at Westminster compared with other medical offices in this Local Market.
In 1996, at the request of CPMG and KFHP leadership, our pharmacy department--in collaboration with nursing, laboratory, and the Medical Group--developed a plan to expand CPAS to the rest of the Local Market (11 medical offices and over 200 physicians). Rollout of the marketwide service began in November, 1996. Our CPAS now manages over 4,200 anticoagulated patients and is staffed by 11 FTEs (1 chief, 2 clinical pharmacy specialists, 6 clinical pharmacists, and 2 pharmacy technicians). Our CPAS has expanded the basic model described to include a comprehensive list of anticoagulation services, including: 1) Outpatient management of approximately 200 episodes of deep vein thrombosis (DVT) each year; 2) Prevention and treatment of venous thromboembolism in about 12 high-risk pregnancies annually by using self-administered unfractionated heparin; 3) Prevention of DVT after orthopedic surgery for the patients of 8 surgeons; 4) Management of anticoagulation therapy in over 100 patients residing in over 50 nursing homes; management of excessive anticoagulation; and 5) Interruption of anticoagulation therapy for invasive procedures (eg, surgery, endoscopy, colonoscopy, and biopsy).
Scope and Significance
Our CPAS staff personally phones over 300 patients daily.
Our CPAS staff manages the patients of more than 200 physicians (internists, family practitioners, orthopedists, cardiologists, obstetricians, perinatologists, rheumatologists, pediatricians, pulmonologists, gerontologists, oncologists, hematologists).
Our CPAS model has recently been implemented in the Kansas City KP Local Market and is being considered by national KP leadership (Division Presidents/Executive Medical Directors) for widespread implementation as a pharmacy/medical quality improvement best practice.
Relevance of Project to Direct Patient Care
Practice Innovation/Leadership; Member/Community
Outpatient Treatment of Deep Vein Thrombosis with Low Molecular
Repackaging Enoxaparin in Patient-specific Dosages
National Benchmark Cost Savings
Anticoagulation Therapy Outcomes
Outcome data for the calendar year 1997 were collected for all patients comprising the first medical office enrolled in the service (East Denver Medical Office). During the same time, similar data were collected for all patients managed by primary care physicians at the last medical office enrolled in the service (Skyline Medical Office). Information was extracted from clinic and hospital medical records, death certificates, and various computerized databases by using standard forms. Data relating to the following variables were collected for each group: demographic information; patient-years of anticoagulation therapy; mean length of anticoagulation therapy during the study period; incidence and costs of every hospitalization and emergency room visit due to complications or failure of anticoagulation therapy; incidence of deaths directly attributable to complications or failure of anticoagulation therapy.
The occurrence of adverse outcomes was verified through objective evidence in all but two cases. Definitions for major bleeding and thromboembolism were as described previously (Figure 1). Risk ratio estimates for the occurrence of hospitalization and death were calculated along with 95% confidence intervals. Cost minimization analysis was performed on the hospitalization data.
Global Benchmark Clinical Outcomes
The results of our analysis identified opportunities to improve management of excessive anticoagulation within our organization (Table 2, Figure 1). Frequent administration of vitamin K (reverses the anticoagulant effect of warfarin) in excessive doses resulted in three cases of resistance to the effects of warfarin, all of which required hospitalization for administration of alternative forms of anticoagulation medication. New clotting complications occurred in two of these cases. For INRs between 6.0 and 10.0, incremental cost effectiveness analysis determined that overzealous treatment with vitamin K is about seven times more costly than conservative management (temporary discontinuation of warfarin therapy until INR declines to within the therapeutic range). Therefore, to prevent one major bleeding episode, an additional $70,500 would be spent treating with vitamin K compared with temporary withdrawal of warfarin therapy.
The 6-month results from reanalysis demonstrated dramatic improvement in the clinical outcomes and management of excessive anticoagulation (Table 2, Figure 1). Because vitamin K was used sparingly (12.4% of episodes before vs 5.4% after CPAS implementation) and in appropriate doses, no patient required hospitalization for iatrogenic thrombosis or for resistance to the effects of warfarin. The percentage of patients receiving vitamin K intramuscularly (a route of administration contraindicated in excessively anticoagulated patients) decreased from 38% to 0%. The total percentage of patients who developed major bleeding decreased from 6.31% (19/301) to 1.19% (4/336) after implementation of our CPAS (relative risk reduction of 82%; 95% confidence interval 47% to 94%). Compared with traditional management, for every 20 episodes of excessive anticoagulation managed by our CPAS, one major hemorrhage is prevented. No major bleeding occurred once the decision to administer vitamin K or to temporarily withhold warfarin therapy was made by CPAS pharmacists compared with two such episodes before implementation of the service. No INR exceeded 20 (a critical value) compared with 17 such episodes before implementation of the service.
Outpatient Treatment of Deep Vein Thrombosis with Low-Molecular-Weight
Beginning in September 1997, our CPAS assumed complete responsibility for administration of the outpatient treatment of DVT program. Through June 30, 1998, an additional 163 patients were treated according to the guideline, resulting in additional $544,728 in cost savings to the organization.
Anticoagulation Therapy Outcomes
Summary of Improved Risk Reduction, Complication Rates, and Associated
Global Benchmark Clinical Outcomes
Figure 3 summarizes how CPAS has documented annualized cost savings of $1,020,000 by providing anticoagulation therapy to members in the Denver/Boulder Local Market.
Total cost savings include:
The collaborative model of our CPAS as developed and implemented by the pharmacy department with assistance and multidisciplinary cooperation of nursing, laboratory, and the Medical Group is currently being considered by national Kaiser Permanente leadership for widespread implementation as a pharmacy/medical quality improvement best practice.
Most health care organizations are either still in the process of implementing similar low-molecular-weight heparin programs or are still in the conceptualization phase. Our program is not only operational--it is a model for other programs nationwide. Our CPAS has garnered local and national recognition for the preeminent care provided to our members needing anticoagulation. We believe that our CPAS model epitomizes the unique power of a group-model managed care organization like Kaiser Permanente to identify and manage high-risk drug therapy patients and to achieve unparalleled clinical outcomes and cost savings.