Anticoagulation in atrial fibrillation. Is there a gap in care for ambulatory patients?

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Anticoagulation in atrial ﬁ brillation

Is there a gap in care for ambulatory patients?

Wayne Putnam, ^MD, ^FCFP Kelly Nicol, ^MSC David Anderson, ^MD, ^FRCP Brenda Brownell, ^CCHRA Meredith Chiasson Frederick I. Burge, ^MD, ^FCFP Gordon Flowerdew, ^PHD Jafna Cox, ^MD, ^FRCP

ABSTRACT

OBJECTIVE Atrial ﬁ brillation (AF) substantially increases risk of stroke. Evidence suggests that anticoagulation to reduce risk

is underused (a “care gap”). Our objectives were to clarify measures of this gap in care by including data from family physicians and to determine why eligible patients were not receiving anticoagulation therapy.

DESIGN Telephone survey of family physicians regarding speciﬁ c patients in their practices.

SETTING Nova Scotia.

PARTICIPANTS Ambulatory AF patients not taking warfarin who had risk factors that made anticoagulation appropriate.

MAIN OUTCOME MEASURES Proportion of patients removed from the care gap; reasons given for not giving the remainder

anticoagulants.

RESULTS Half the patients thought to be in the care gap had previously unknown contraindications to anticoagulation, lacked

a clear indication for anticoagulation, or were taking warfarin. Patients’ refusal and anticipated problems with compliance and monitoring were among the reasons for not giving patients anticoagulants.

CONCLUSION Adding data from primary care physicians signiﬁ cantly narrowed the care gap. Attention should focus on the

remaining reasons for not giving eligible patients anticoagulants.

RÉSUMÉ

OBJECTIF La ﬁ brillation auriculaire (FA) augmente considérablement le risque d’accident vasculaire cérébral. Les données

scientiﬁ ques donnent à croire que l’anticoagulothérapie pour réduire le risque n’est pas suﬃ samment utilisée (une «lacune dans les soins». Nos objectifs étaient de préciser l’ampleur de cette lacune dans les soins en tenant compte des données provenant des médecins de famille et de déterminer les raisons pour lesquelles des patients admissibles à une anticoagulothérapie ne la recevaient pas.

CONCEPTION Un sondage téléphonique auprès de médecins de famille concernant des patients spéciﬁ ques dans leur pratique.

CONTEXTE La Nouvelle-Écosse.

PARTICIPANTS Des patients de cliniques externes souﬀ rant de FA ne prenant pas de warfarine et ayant des facteurs de risque

justiﬁ ant une anticoagulothérapie.

PRINCIPALES MESURES DES RÉSULTATS La proportion de patients exclus de la lacune dans les soins; les motifs justiﬁ ant de

ne pas avoir donné aux autres des anticoagulants.

RÉSULTATS Il existait, chez la moitié des patients qu’on pensait «manquer» de soins, des contre-indications auparavant

inconnues de suivre une anticoagulothérapie; il n’était pas clairement indiqué chez ceux-ci de prendre des anticoagulants; ou encore, ils prenaient de la warfarine. Le refus des patients et les problèmes anticipés entourant la conformité et la surveillance comptaient au nombre des raisons de ne pas donner des anticoagulants aux patients.

CONCLUSION L’ajout de données provenant des médecins de première ligne réduit considérablement l’ampleur de la lacune

dans les soins. Il faudrait insister sur les autres raisons de ne pas administrer aux patients admissibles une anticoagulothérapie.

This article has been peer reviewed.

Cet article a fait l’objet d’une évaluation externe.

Can Fam Physician 2004;50:1244-1250.

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trial fibrillation (AF) has a prevalence of between 2% and 10% among elderly people^1,2 and will become an increasingly important health issue in our aging population. It is of par- ticular concern because patients with AF have an almost ﬁ vefold increased risk of stroke,³ which can be substantially reduced by treating those at high risk.^4-6 Evidence on beneﬁ t and risk of anticoagulation was comprehensively reviewed by a Canadian Cardiovascular Society Consensus Conference.⁷ Th is review resulted in grade A recommendations based on level I evidence (randomized controlled trials) that were published in January 1996.⁷

Despite strong evidence in the literature since 1991⁴ in favour of anticoagulation, studies of AF patients of general practitioners in the United Kingdom revealed anticoagulation rates of only 21.4%,² 36%,^8,9 and 52%.¹⁰ A variety of reasons were reported for not using anticoagulants.

Th ese included patients’ wishes,^2,9,10 dementia,^2,8 frailty or falls,^2,8 age or “extreme age,”^2,8-10 multiple comorbid conditions,² “consultant’s opinion,”⁹ risk outweighs beneﬁ ts,⁹ dyspepsia,⁸ anticipation of problems with compliance or monitoring,² and being housebound.² Among a national sample of ambulatory AF patients in the United States, 43%

of those with additional risk factors for stroke were treated with anticoagulants.¹¹ Two thirds of Canadian patients with AF who had been in a trial of anticoagulant therapy were treated with warfarin after the study was terminated.¹² Reasons for not prescribing warfarin included patient prefer- ence (67%), risk outweighing beneﬁ ts (16%), ace- tylsalicylic acid preferred to warfarin (10%), and a

“nuisance” factor (7%).

We define the “care gap” as the proportion of patients with no known contraindications to warfarin therapy and for whom warfarin is indicated who remain untreated. Evidence shows that this gap has narrowed in recent years. Th e ﬁ rst Canadian study we found, of AF patients recruited from an academic family medicine practice in Toronto, reported that 78.2% were taking warfarin in 1999 and 2000.¹³ A baseline measure in an unpublished population-based study in Nova Scotia, using information provided by AF patients, found that 69.2%

were receiving anticoagulant therapy. We believed that family physicians could shed some light on the remaining 30.8% gap in that study. Our objectives were to enhance measurement of this gap by adding data on ambulatory patients from community family physicians and to determine whether reasons for not treating patients are diﬀ erent now that the care gap appears to be narrowing.

METHODS Design and setting

Th is study was a census survey by telephone of family physicians throughout Nova Scotia who had one or more eligible patients in their practices.

Sample frame and subjects

Patients were identiﬁ ed from a database created for a population-based study of patients with AF living in the community. Th ese patients were found through a survey of electrocardiogram facilities throughout Nova Scotia between November 1999 and March 2001. Of the 425 patients in the study database in March 2001, 71 remained apparently Dr Putnam is a family physician and researcher, and

Ms Nicol is a Research Associate, both in the Department of Family Medicine at Dalhousie University in Halifax, NS. Dr Anderson is a Professor in the Department of Medicine and Head of the Division of Hematology at Dalhousie University. Ms Brownell is a Project Coordinator in Health Outcomes Research in the Division of Cardiology at the Queen Elizabeth II Health Sciences Centre (QEIIHSC) in Halifax. Ms Chiasson is a fourth- year medical student at Dalhousie University. Dr Burge is a family physician, an Associate Professor of Family Medicine, and an Assistant Professor in the Department of Community Health and Epidemiology at Dalhousie University. Dr Flowerdew is a biostatistician in the Department of Community Health and Epidemiology at Dalhousie University. Dr Cox is an Associate Professor in the Departments of Medicine and Community Health and Epidemiology at Dalhousie University and a Staﬀ Cardiologist at the QEIIHSC.

trial fibrillation (AF) has a prevalence of between 2% and 10% among elderly people and will become an increasingly important health issue in our aging population. It is of par-

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eligible for anticoagulation but untreated. Th ese 71 patients constituted the apparent care gap and formed our sample. Patients were contacted by telephone by the study coordinator (B.B.) to obtain consent for us to approach their family physicians, who were subsequently also recruited by letter and telephone.

Collection and analysis of data

An interview guide was used. It contained an open-ended invitation to tell the inter- viewer why a patient was not being treated with anticoagulants. A checklist of possible responses drawn from previous UK studies^2,8-10 was included, as was an “other” option.

Physicians were encouraged to refer to their patients’ charts to complement their memories.

This step was taken to ensure reliable information. All interviews were conducted by trained interviewers (B.B. and K.N.) who documented all reasons for not giving patients anticoagulation therapy. Analysis consisted of descriptive statistics of categorical data.

The research ethics board of the Queen Elizabeth II Health Sciences Centre in Halifax, NS, approved the study’s protocol and that of the initial study from which our sample was drawn.

Signed consent was obtained from both patients and family physicians.

RESULTS

The 53 (74.6%) patients who agreed to partici- pate had an average age of 70.4 (standard devi- ation 12.1, range 28 to 90 years); 34 were male (64%). Seventeen patients refused to be included in our study, as did one family physician (Figure 1).

Th us we do not know the anticoagulation status of 18 patients. Seven patients were reported to have started taking warfarin since the sample was drawn, leaving 46 patients whose family physicians we interviewed.

Of the 46 patients, 20 were found to have either previously unknown contraindications or no appropriate indication for warfarin therapy (Figure 2). Substantial bleeding was the most Figure 1. Anticoagulation status of subjects

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common contraindication (n = 7, including five with gastrointestinal bleeding). A consultant had contributed to decisions about therapy for four of these seven patients. Two patients reacted or were intolerant to warfarin (a “significant” skin rash for one, and nausea and vomiting for the other). Three patients had had single episodes of AF as a consequence of acute self-limited triggers (infection, heart surgery, or hospitaliza- tion for unspecified cause). No current evidence justifies using anticoagulants for these patients.

The remaining 26 patients had indications for warfarin therapy but were not being treated.

Two reasons were given for not treating each of three patients, for a total of 29 responses. The most common reason for not being treated was patients’ refusal (seven patients) (Figure 3). Single episodes, usually remote, without a known trigger (ﬁ ve patients) and paroxysmal AF (four patients) were also cited. The decision not to treat was made or shared by a consultant for eight of these nine patients. Actual or anticipated problems with compliance and monitoring, based on previous

experiences with patients, were the reason for not treating ﬁ ve patients, one of whom was also reported to have dementia (her family physician believed her caregiver would not have been able to comply with treatment and blood monitoring). One patient’s physician said the patient was younger than 65 and that therapy was not indicated. Th is patient was originally included in the study because he had hypertension, a major risk factor.

Within the group of 26 patients, 16 saw consultants as well as their family physicians. For four patients, family physicians indicated “consultant judgment” as the only reason for with- holding treatment. One patient was not offered anticoagulants because of continuing nonsteroi- dal anti-inflammatory therapy. No reason was offered for one patient who had multiple comorbid conditions; the family physician labeled it an “oversight” on his or her part, although the patient had seen three separate consultants in emergency settings and had received no recom- mendation for anticoagulation.

common contraindication (n = 7, including five experiences with patients, were the reason for

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Figure 2. Patients for whom warfarin is not indicated or contraindicated: N=20.

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DISCUSSION

Our results, in comparison with reports reviewed above, suggest that the care gap continues to nar- row. Of the 425 patients in the initial database, 71 appeared to be in the care gap, and our sample included 75% (53/71) of them. Adding data from family physicians removed 50.9% (27/53) of these patients from the gap. We suggest that researchers exercise caution when dealing with clinical conditions largely managed in ambulatory care (by primary physicians and consultants). Signiﬁ cant esti- mation errors could occur when data on ambulatory patients are not included in their investigations.

Some of the reasons noted in earlier studies for not using anticoagulants persist. The most common reason for being in the care gap in our study is patient refusal, also called patient pref- erences or wishes in Canadian and UK studies.

Use of appropriate patient education materials or aids to decision making¹⁴ might help ensure that patients are making truly informed decisions, but respect for patient choice implies that the number of patients who could beneﬁ t from

anticoagulation, but refuse treatment, will not diminish to zero. Knowing truly achievable rates of implementation of such therapy is important in a world of proposed payment incentives for practice.¹⁵ It might be proposed that a family practice receive additional payments from health insur- ance plans if, for example, 80% of patients with AF in the practice are treated. Such targets must be based on evidence of what is achievable, not on “best guesses.” Th ere is also an ethical issue:

are patients to be counted in the gap if they have made an informed choice not to be treated?

Another factor observed in our study and cited in the UK studies for not prescribing warfarin was anticipated problems with compliance and monitoring. Although patient-specific issues accounted for some of these (eg, noncompli- ance with other treatment regimens in the past), other concerns, such as lack of transportation for patients or their blood samples to the laboratory, could be overcome by community venipunc- ture services or volunteer drivers. A structured anticoagulation clinic in a primary care setting in the United States has recently been shown to improve monitoring and INR (International anticoagulation, but refuse treatment, will not

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Figure 3. Reasons for not treating patients for whom anticoagulation is indicated:Th ree patients gave two reasons for a total of 29 reasons for 26 people (N=26).

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Normalized Ratio) control.¹⁶ Further research should be done to identify and test strategies to reduce these anticipated problems or remove this barrier to optimal care.

One reason for avoiding anticoagulation not observed in previous studies is diagnosis of a single episode of AF without known trigger or paroxysmal AF. We acknowledge that most evidence supporting anticoagulation has been developed in trials of chronic AF and that evidence regarding paroxysmal AF is much less convincing. It is possible that community specialists and family physicians are uncertain whether the evidence applies to these patients or whether they or the patients themselves believe the risks outweigh the possible beneﬁ ts.

A high proportion (16/26, 62%) of patients who were not using anticoagulants saw consultants as well as their family physicians. Whether consultants were called to help with managing patients’

arrhythmias or anticoagulation or both is unclear.

Th e clinical judgment of a consultant, also seen in UK data, was the only reported reason for not giving anticoagulants to four patients. Th e decision not to treat another patient (with hypertension) because he was younger than 65 years is consis- tent with other studies,^17,18 suggesting that hypertension is not recognized or accepted as a risk factor. Th is belief can be modiﬁ ed through continuing medical education.

It is useful to note some reasons reported in other studies but not off ered in this study. Old age (or “extreme age”) was not a justifi cation for avoiding anticoagulation in this study as it was in many earlier studies.2,8-10,17,19,20 Although our sample is small, this result could indicate that the message that benefi ts outweigh risks for elderly people as well as younger people has been accepted by physicians and patients. Multiple comorbid conditions were also not off ered as a justifi cation for not treating patients.

Limitations

The generalizability of our results might be limited by the type of patients who were successfully

recruited into the original study. Although vig- orous efforts were made to identify all patients with electrocardiographic (ECG) diagnoses of AF in Nova Scotia, not all ECG facilities cooperated, and not all physicians and patients were willing to be involved. Because the treatment rate was high, our sample in the care gap was therefore small, and the numbers for each reason for not using anticoagulants were very small. The accuracy of patient self-reported information regarding risk factors and contraindications was not validated by checking with physicians or hospi- tal records. Similarly, the accuracy of information gathered at interviews with physicians could not be validated, and the appropriateness of their judgment regarding relative contraindications could not be considered.

recruited into the original study. Although vig-

EDITOR’S KEY POINTS

• Although anticoagulation is recommended for most patients with atrial ﬁ brillation (level I evidence), several studies have shown less than optimal anticoagulation coverage in practice.

• Two Canadian studies have shown about 70% compliance with warfarin therapy, leaving a “care gap” of about 30%. In this survey of Nova Scotia family physicians, a care gap of 17% was halved when reasons for not prescribing warfarin were revealed.

• Common reasons for not prescribing warfarin were substantial bleeding, malignancy, excessive alcohol intake, patients’ refusal, and anticipated problems with monitoring and compliance.

• Researchers could signiﬁ cantly underestimate coverage of patients in ambulatory care if data are not obtained directly from primary care settings.

POINTS DE REPÈRE DU RÉDACTEUR

• Même s’il est recommandé d’administrer une anticoagulothérapie à la plupart des patients ayant une ﬁ brillation auriculaire (donnée de niveau I), plusieurs études ont fait valoir que cette pratique est loin d’être optimale.

• Deux études canadiennes ont démontré une conformité d’environ 70% à la thérapie à la warfarine, laissant une «lacune dans les soins» de quelque 30%. Dans le présent sondage auprès des médecins en Nouvelle-Écosse, une lacune dans les soins de 17% a été réduite de moitié lorsque les motifs de ne pas prescrire de la warfarine ont été révélés.

• Au nombre des raisons les plus fréquentes de ne pas prescrire de la warfarine ﬁ guraient des saignements substantiels, un cancer, une consommation abusive d’alcool, le refus des patients et les pro- blèmes anticipés entourant la surveillance et la conformité.

• Les chercheurs sont susceptibles de sous-estimer considérablement la couverture des patients en soins ambulatoires si des données ne sont pas obtenues directement des milieux de soins de première ligne.

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Conclusion

The care gap in anticoagulation of patients with AF who are at increased risk of stroke appears nar- rower than previously reported after data from family physicians’ practices are included. Some previously recorded reasons for not using anticoagulants, such as patients’ refusal and anticipated problems with compliance and monitoring, persist, but old age and multiple comorbid conditions were not cited as reasons in our study.

Acknowledgment

The authors thank Dr Martin Gardner for his contri- bution to the review of each patient’s record in the ini- tial population-based study from which our sample was drawn. This work was vital to the deﬁnition of patients eligible for inclusion in our study. Dr Burge is supported by a Senior Clinical Research Scholar career award from the Faculty of Medicine at Dalhousie University in Halifax, NS. Dr Cox receives salary support from a Canadian Institutes of Health Research/Regional Partnership Program Investigator Award and from a Clinical Research Scholarship from the Faculty of Medicine at Dalhousie University. This project was funded by the Nova Scotia Health Research Foundation. The population-based study from which our sample was drawn was funded by the Heart and Stroke Foundation of Nova Scotia.

Contributors

Dr Putnam participated in conception and design of the project and analysis and interpretation of data, and he drafted most of the article. Ms Nicol participated in acquiring, analyzing, and interpreting the data and drafted components of the paper and revised it critically.

Drs Anderson, Burge, and Cox and Mr Flowerdew par- ticipated in conception and design of the project, analysis and interpretation of data, and revising the manuscript for critical content. Ms Brownell participated in concep- tion and design of the project, acquisition of data, and

revising the manuscript critically. Ms Chiasson partici- pated in analyzing and interpreting the data and revis- ing drafts of the paper for critical content. All the authors gave ﬁnal approval to the manuscript submitted.

Competing interests None declared

Correspondence to: Dr Wayne Putnam, Dalhousie University, Department of Family Medicine, Abbie J. Lane Bldg, 8th ﬂoor, 5909 Veterans Memorial Ln, Halifax, NS B3H 2E2; telephone (902)-473-4740; fax (902)-473-4760; e-mail [email protected] References

1. Krahn AD, Manfreda J, Tate RB, Mathewson FA, Cuddy TE. The natural history of atrial ﬁbrillation: incidence, risk factors and prognosis in the Manitoba Follow-Up Study. Am J Med 1995;98:476-84.

2. Wheeldon NM, Tayler DI, Anagnostou E, Cook D, Wales C, Oakley GD. Screening for atrial ﬁbrillation in primary care. Heart 1998;79(1):50-5.

3. Wolf PA, Abbott RD, Kannel WB. Atrial ﬁbrillation as an independent risk factor for stroke: the Framingham study. Stroke 1991;22(8):983-8.

4. Stroke Prevention in Atrial Fibrillation Investigators. Stroke prevention in atrial ﬁbrillation study: ﬁnal results. Circulation 1991;84(2):527-39.

5. Boston Area Anticoagulation Trial for Atrial Fibrillation Investigators. The eﬀect of low- dose warfarin on the risk of stroke in patients with nonrheumatic atrial ﬁbrillation. N Engl J Med 1990;323(22):1505-11.

6. Connolly SJ, Laupacis A, Gent M, Roberts RS, Cairns JA, Joyner C. Canadian Atrial Fibrillation Anticoagulation (CAFA) Study. J Am Coll Cardiol 1991;18(2):349-55.

7. Connolly SJ, Turpie AG. Antithrombotic therapy in atrial ﬁbrillation. Can J Cardiol 1996;12(Suppl A):17-20A.

8. Lip GY, Golding DJ, Nazir M, Beevers DG, Child DL, Fletcher RI. A survey of atrial ﬁbril- lation in general practice: the West Birmingham Atrial Fibrillation Project. Br J Gen Pract 1997;47(418):285-9.

9. Oswald N, Bateman H. Applying research evidence to individuals in primary care: a study using non-rheumatic atrial ﬁbrillation. Fam Pract 1999;16(4):414-9.

10. Howitt A, Armstrong D. Implementing evidence based medicine in general practice: audit and qualitative study of antithrombotic treatment for atrial ﬁbrillation. BMJ 1999;318(7194):1324-7.

11. Staﬀord RS, Singer DE. Recent national patterns of warfarin use in atrial ﬁbrillation.

Circulation 1998;97(13):1231-3.

12. Laupacis A, Sullivan K. Canadian atrial ﬁbrillation anticoagulation study: were the patients subsequently treated with warfarin? Canadian Atrial Fibrillation Anticoagulation Study Group. CMAJ 1996;154(11):1669-74.

13. Ceresne L, Upshur RE. Atrial ﬁbrillation in a primary care practice: prevalence and man- agement. BMC Fam Pract [serial online] 24-5-2002; [cited 17-10-2003] 3(11):[6 screens].

Available from: www.biomedcentral.com/1471-2296/3/11. Accessed 2004 July 15.

14. Man-Son-Hing M, Laupacis A, O’Connor AM, Biggs J, Drake E, Yetisir E, et al. A patient decision aid regarding antithrombotic therapy for stroke prevention in atrial ﬁbrillation: a randomized controlled trial. JAMA 1999;282(8):737-43.

15. Hughes D. General practitioners and the new contract: promoting better health through ﬁnancial initiatives. Health Policy 1993;25(1-2):39-50.

16. Chamberlain MA, Sageser NA, Ruiz D. Comparison of anticoagulation clinic patient outcomes with outcomes from traditional care in a family medicine clinic. J Am Board Fam Pract 2001;14(1):16-21.

17. Burton CD, Hamilton KES, Isles CG, Norrie J. Warfarin for nonvalvular atrial ﬁbrillation in primary care—another example of the age paradox? J Cardiovasc Risk 2001;8(5):307-9.

18. Rutten FH, Hak E, Stalman WAB, Verheij TJM, Hoes AW. Is treatment of atrial ﬁbrillation in primary care based on thromboembolic risk assessment? Fam Pract 2003;20(1):16-21.

19. Cohen N, Almoznino-Saraﬁan D, Alon I, Gorelik O, Koopfer M, Chachashvily S, et al.

Warfarin for stroke prevention still underused in atrial ﬁbrillation. Stroke 2000;31(6):1217-22.

20. Ruigómez A, Johansson S, Wallander M, Rodríguez G. Incidence of chronic atrial ﬁbrilla- tion in general practice and its treatment pattern. J Clin Epidemiol 2002;55:358-63.

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