An Audit of Prescribing Practice for Clopidogrel in Primary Care

Tammy Lo

Description

JSMSCARDIOLOGY & RESPIRATORY MEDICINEAn Audit of Prescribing Practice for Clopidogrel in Primary CareTammy LoKing’s College London School of Medicine, United KingdomIntroductionClopidogrel (Plavix®) is a powerful antiplatlet drug. Its usage in combina- Corresponding authortion with aspirin has become the standard of care in management of a wide Tammy Lovariety of cardiovascular diseases. Its molecular mechanism of action is in e: [e-mail] interaction between adenosine diphosphate and the G-protein coupled P2Y 12 purinergic receptor located on the surface of platelet cells. Conflicts of interestNone declaredNICE guidelines [1, 2] direct the duration of clopidogrel usage in the secondary prophylaxis of atherothrombotic events following:1) a recent ACS episode2) a recent myocardial infarction3) a recent occlusive vascular event4) with established peripheral vascular disease5) coronary artery bypass grafting (CABG).The duration of aspirin and clopidogrel dual therapy is recommended in the NICE guidelines.12 months post NSTEMIAt least four weeks post STEMIFour weeks post-CABG surgeryThe British Cardiovascular Intervention Society [3] recommends dual therapy prior and following a percutaneous coronary inter-vention (one month following bare metal stent insertion and 12 months following drug-eluting stent insertion). Clopidogrel/aspi-rin dual therapy is limited by an increased risk of bleeding. Furthermore, clopidogrel ...

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CARDIOLOGY & RESPIRATORY MEDICINE

An Audit of Prescribing Practice for Clopidogrel in Primary Care

Tammy Lo King’s College London School of Medicine, United Kingdom

Introduction

Clopidogrel (Plavix®) is a powerful antiplatlet drug.Its usage in combina- tion with aspirin has become the standard of care in management of a wide variety of cardiovascular diseases. Its molecular mechanism of action is in blocking interaction between adenosine diphosphate and the G-protein coupled P2Y 12 purinergic receptor located on the surface of platelet cells.

NICE guidelines [1, 2] direct the duration of clopidogrel usage in the secondary prophylaxis of atherothrombotic events following:

1) arecent ACS episode 2) arecent myocardial infarction 3) arecent occlusive vascular event 4) withestablished peripheral vascular disease 5) coronaryartery bypass grafting (CABG).

Corresponding author Tammy Lo e: [e-mail]

Conflicts of interest None declared

The duration of aspirin and clopidogrel dual therapy is recommended in the NICE guidelines.

12 months post NSTEMI At least four weeks post STEMI Four weeks post-CABG surgery

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The British Cardiovascular Intervention Society [3] recommends dual therapy prior and following a percutaneous coronary inter- vention (one month following bare metal stent insertion and 12 months following drug-eluting stent insertion). Clopidogrel/aspi- rin dual therapy is limited by an increased risk of bleeding. Furthermore, clopidogrel prescription is relatively expensive [4]. En- suring clopidogrel is discontinued when no longer indicated is important to limit bleeding risks and appropriately allocate funds.

The aim of this audit is to identify the appropriateness of clopidogrel usage according to the NICE guidelines in pa- tients who were initially prescribed clopidogrel 12 months or more previously in an East London primary care practice.

Methods

Electronic clinical records of patients treated within an East London primary care practice are prospectively updated on the Consultation Manager system. The system was interrogated to find all patients within the practice that had re- ceived a prescription for clopidogrel in the preceding 12 months.This includes some patients that had been commenced on clopidogrel previously.The search revealed 34 patients.Consultation re- cords, primary care prescriptions and hospital discharge notifications were re-

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viewed for every patient.Data was col- lected on patient demographics, indica- tion for treatment, intended and actual duration of course and whether the in- tended duration of course was specified on hospital discharge.A Microsoft Excel database was created and the data input.

The main objectives of this audit are to:

1) determinethe success of adherence to NICE guidelines

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2) toexplore factors that lead non-ad- herence with guidelines

3) tosuggest a strategy to improve the prescription of clopidogrel 4) toschedule re-audit after a suitable time period (loop-closure)

Data was analysed using Microsoft Excel.

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Results

Figure 1:Within the 34 patients in the audit, few patients were under the age of 50. Sixteen patients (47%) were in the elderly category.

Figure 4:Discharge summaries for each patient were reviewed. The vast majority did not explicitly state the intended duration of clopidogrel therapy.

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Figure 2:There were more male patients (70%) who were taking clopidogrel when compared to female patients.

Figure 3:Vast majority of patients had indica- tions listed in the discharge summary related to coronary artery disease. Some had greater specification into on ST elevation MI (STEMI). A proportion of patients underwent percutaneous intervention (15 patients) for their coronary dis- ease. Of those, 47% underwent bare metal stent- ing, 53% underwent drug eluted stenting.Three patients were commenced on clopidogrel fol- lowing transient ischaemic attacks, one follow- ing stenting of peripheral vascular stenosis and one for the treatment of atrial fibrillation. Un- fortunately, hospital discharge notification was insufficiently clear in one patient and suggested the indication for treatment was “chest pain?”.

Figure 5:Notably 16 patients continue to be on clopidogrel af- ter 2 years. This contrast strongly with the fact that only 5 pa- tients were intended to be on clopidogrel for over 12 months.

Figure 4:Five of the thirty-four patients included in this audit have indications for lifelong clopidogrel treatment. Twelve have had their clopidogrel treatment stopped prior to commencement of this audit. I discovered a further 17 patients who continue to take clopidogrel beyond their indicated durations. It is impor- tant that that be reviewed with consideration of discontinuing clopidogrel.

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Discussion The CURE trial demonstrated dual anti-patient information or illegible writing, platlet therapy (aspirin and clopidogrel)causing a communication breakdown was more effective than aspirin plus abetween hospitals and primary care. It The advent and widespread usage of placebo in treatment of NSTEMI (com-seems reasonable to examine how this clopidogrel is a breakthrough in man- posite endpoints: death by cardiovascu-system can be improved. Electronic dis- agement of cardiovascular disease.It lar cause, non-fatal MI and stroke duringcharge has been successfully introduced has augmented established treatment treatment course).However, patientsto many hospitals throughout the UK. regimen of common pathologies (e.g. on dual antiplatlet therapy had signifi-Discharge summaries created electroni- myocardial infarction) and permitted cantly more bleeding complications [8].cally can be designed to incorporate man- technological breakthrough (usage of datory fields. These fields would need to drug eluting coronary stents).To re- This audit looks at the prescribing pat-be filled in before the document can be alise the potential of this exciting new tern of clopidogrel, particularly indica-completed and signed off. We suggest drug, accurate prescription is crucial. tions for usage and duration of adminis-that communication regarding length tration. Assessment morbidity associateof intended drug course could be opti- Historical review of the literature reveals with clopidogrel usage in this popula-mised by using the above mechanism. that initial attempts at percutaneous tion is beyond the scope of this audit. coronary artery intervention were com- It is recognised that attempts to ratio- plicated by thrombosis and acute occlu- The audit identified that the intendednalise duration of antiplatlet therapy sion. In an effort to enhance the efficacy duration of clopidogrel was often un-are not aided by suboptimal communi- of angioplasty – a number of specific clear or absent on hospital dischargecation of discharge plans form second- coronary artery stents were developed. summaries and many patients had re-ary/tertiary care institutes. Taking into Initial attempts were bare metal devices mained on clopidogrel for over 2 years.account the small volume of patients of varied conformations. Problems en- on clopidogrel as well the potential fi- countered with the utilisation of this In most cases, when clopidogrel isnancial and clinical implications of technology were in-stent thrombosis and continued for such a prolonged pe-prolonged therapy, it seems feasible to troubling re-stenosis due to neo-intimal riods, the benefit is outweighed requestclarification directly from hospi- hyperplasia [5]. More recently, develop- by significant haemorrhagic risks. talphysicians when discharge notifica- ment of stents that slowly release drugs tions are ambiguous. This may enhance to prevent neo-intimal hyperplasia has As a relatively new drug, clopidogrelthe accuracy of future correspondences. massively reduced in-stent re-stenosis. remains protected by a patent until However, the absence of a functioning 2011. It is sold in the UK under the tradeThis audit identifies and reviews an im- intima means the lumen of the stent is name Plavix ®.It is estimated that ge-portant area of deficiency in service. a localised area of intense thrombogenic neric form clopidogrel is sold for justTo establish the success of this audit potential. Large randomised controlled 3% of the price of Plavix ® [9]. Whenit is necessary to re-audit the clopido- trials have demonstrated and increased working within a system with finite fi-grel prescription practices. The recom- efficacy and safety profile of antiplat- nancial reserves, it is important to al-mended temporary duration of clopi- let treatment over anticoagulation [6]. locate resources appropriately. Clearlydogrel usage following an acute event The accepted optimal treatment post the erroneous continued prescriptionis 1 month to 1 year. Therefore re-au- implantation of a drug eluting stent is of clopidogrel is beyond intended dura-dit should take place in 2 years time. 12 months of dual antiplatlet therapy tion detrimental to funding patient care. with clopidogrel and aspirin. Drug al- References lergies, adverse reactions and medi- The usage of information technolo- cal history may require this regimen 1. National Institute for Health and Clinical gies in the primary care practice is now to be tailored to individual patients. Excellence. (2004). Clopidogrel in the treat- well established.Automated repeat ment of non-ST segment elevation acute prescriptions are widely utilised. The An important study that helped estab- coronary syndromes. Available: http://guid- Consultation Manager used in the sur- lish the role of clopidogrel in everyday ance.nice.org.uk/TA80. Last accessed 22 gery audited has a built in function for clinical practice was the CAPRIE trial. March 2009. scheduling review or discontinuation of It was an international, randomised a prescription. It is recommended that and blinded study that enrolled almost 2. National Institute for Health and Clinical this function be used when clopidogrel Excellence. (2007). Secondary prevention 20,000 patients.It demonstrated clopi- therapy is initiated in primary care. in primary and secondary care for patients dogrel (75mg OD) was slightly more ef- following a myocardial infarction. Available: fective than aspirin (325mg OD) in re- http://guidance.nice.org.uk/CG48. Last ac- In order for primary care to appropriate- duction the risk of ischaemic stroke, MI cessed 22 March 2009. ly continue medications commenced in or vascular death in patients with ath- hospital, clear and comprehensive com- erosclerotic vascular disease. This dif- 3. Cardiovascular Interventional Society munication needs to occur. This is usu- ference was not statistically significant. council. (2007). BCIS council statement on ally done in the form of discharge sum- Furthermore, there was no difference stent thrombosis and drug eluting stents. maries or as “to take away forms”. The in the number of haemorrhagic com- Available: http://www.bcis.org.uk/news/ system often fails due to inadequacy of News1739. Last accessed 20 March 2009. plications between the two agents [7].

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4. Main C, Palmer S, Griffin S, Jones L, Orton V, Sculpher M, Henderson R, Sudlow C, Hawkins N, Riemsma R. (2004). Clopidogrel used in combination with aspirin compared with aspirin alone in the treatment of non- ST-segment-elevation acute coronary syn- dromes: a systematic review and economic evaluation. Health Technol Assess. 8 (40), 1-141.

5. Topol, E. (1994). Caveats about Elective Coronary Stenting. NEJM. 331 (8), 539-541.

6. Schomig, A, Neumann, F, Kastrati, A, Schühlen, H, Blasini, R, Hadamitzky, M,

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Walter, H, Zitzmann-Roth, E, Richardt, G, Alt, E, Schmitt, C, Ulm, K . (1996). A Ran- domized Comparison of Antiplatelet and Anticoagulant Therapy after the Placement of Coronary-Artery Stents. NEJM. 334 (17), 1084-1089.

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7. CAPRIE Steering Committee. (1996 ). A ran- domised, blinded, trial of clopidogrel versus aspirin in patients at risk of ischaemic events (CAPRIE). Lancet. 16 (348), 1329-39.

8. Fox KA, Mehta SR, Peters R, Zhao F, Lakkis N, Gersh BJ. (2004). Benefits and risks of the combination of clopidogrel and aspirin in pa-

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tients undergoing surgical revascularization for non-ST-elevation acute coronary syn- drome: the Clopidogrel in Unstable angina to prevent recurrent ischemic Events (CURE) Trial. Circulation . 110 (10), 1202-1208.

9. Shuchman, M. (2006). Delaying Generic Competition – Corporate Payoffs and the Future of Plavix. NEJM. 355 (13), 1297-1300.

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