Accuracy of Vitalograph lung monitor as a screening test for COPD in primary care.

Microspirometry may be useful as the second stage of a screening pathway among patients reporting respiratory symptoms. We assessed sensitivity and specificity of the Vitalograph® lung monitor compared with post-bronchodilator confirmatory spirometry (ndd Easy on-PC) among primary care chronic obstructive pulmonary disease (COPD) patients within the Birmingham COPD cohort. We report a case-control analysis within 71 general practices in the UK. Eligible patients were aged ≥40 years who were either on a clinical COPD register or reported chronic respiratory symptoms on a questionnaire. Participants performed pre- and post-bronchodilator microspirometry, prior to confirmatory spirometry. Out of the 544 participants, COPD was confirmed in 337 according to post-bronchodilator confirmatory spirometry. Pre-bronchodilator, using the LLN as a cut-point, the lung monitor had a sensitivity of 50.5% (95% CI 45.0%, 55.9%) and a specificity of 99.0% (95% CI 96.6%, 99.9%) in our sample. Using a fixed ratio of FEV1/FEV6 < 0.7 to define obstruction in the lung monitor, sensitivity increased (58.8%; 95% CI 53.0, 63.8) while specificity was virtually identical (98.6%; 95% CI 95.8, 99.7). Within our sample, the optimal cut-point for the lung monitor was FEV1/FEV6 < 0.78, with sensitivity of 82.8% (95% CI 78.3%, 86.7%) and specificity of 85.0% (95% CI 79.4%, 89.6%). Test performance of the lung monitor was unaffected by bronchodilation. The lung monitor could be used in primary care without a bronchodilator using a simple ratio of FEV1/FEV6 as part of a screening pathway for COPD among patients reporting respiratory symptoms.

Is screening for AF worthwhile? Stroke risk in a screened population from the SAFE study.

INTRODUCTION: Atrial fibrillation (AF) is an important independent risk factor for stroke and oral anticoagulation therapy provides a highly effective treatment to reduce this risk. Active screening strategies improve detection of AF in comparison with routine care; however, whether screen-detected patients have stroke risk profiles favouring anticoagulation is unclear. Using data derived from the screening for AF in the elderly (SAFE) study, the aim of this article was to determine if patients with AF detected via active screening have stroke risk profiles that warrant prophylactic anticoagulation. METHODS: Secondary analysis of data derived from 25 general practices within which cohorts of 200 patients were randomly allocated to opportunistic [pulse and electrocardiogram (ECG)] or systematic screening (postal invitation for ECG). Stroke risk assessment was undertaken using baseline data extracted from medical records and CHADS2 criteria. CHADS2 scores were compared between the screening groups. RESULTS: One hundred and forty-nine new cases of AF were detected, 75 via opportunistic screening and 74 via systematic screening. CHADS2 scores were ≥1 in 83% [95% confidence interval (CI) 72.6-89.6] of patients detected via opportunistic screening and 78% (95% CI 67.7-86.2) detected via systematic screening. There were no significant differences in stroke risk profiles of patients detected via opportunistic and systematic screenings. CONCLUSION: Stroke risk profiles of patients detected via opportunistic and systematic screenings were similar. Data derived from the SAFE study suggest that active screening for AF in patients aged ≥65 years in primary care is a useful screening programme with 78-83% of patients identified eligible for anticoagulation treatment according to the CHADS2 criteria.

Combined anticoagulation and antiplatelet therapy for high-risk patients with atrial fibrillation: a systematic review.

BACKGROUND: Previous research suggests uncertainty whether or not there is any additional benefit in adding antiplatelet therapy (APT) to anticoagulation therapy (ACT) in patients with high-risk atrial fibrillation (AF) in terms of reduction in vascular events, including stroke. The existing guidelines acknowledge an increased risk of bleeding associated with such a strategy; however, there is no consensus on the treatment pathway. OBJECTIVES: To determine, by undertaking a systematic review, if the addition of APT to ACT is beneficial compared with ACT alone in patients with AF who are considered to be at high risk of thromboembolic events (TEs). DATA SOURCES: Data sources included bibliographic databases {the Cochrane Library [Cochrane Central Register of Controlled Trials (CENTRAL)], MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, ClinicalTrials.gov, National Institute for Health Research (NIHR) Clinical Research Network Portfolio, Current Controlled Trials (CCT) and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP)}, reference lists from identified systematic reviews and relevant studies, and contact with clinical experts. Searches were from inception to September 2010 and did not use language restrictions or study design filters. REVIEW METHODS: Studies of any design were included to evaluate clinical effectiveness, including randomised controlled trials (RCTs), non-randomised comparisons, cohort studies, case series or registries, longitudinal studies, systematic reviews and meta-analyses, and conference abstracts published after 2008. Inclusion criteria consisted of a population with AF, at high-risk of TEs, aged ≥ 18 years, on combined ACT and APT compared with others on ACT alone or ACT plus placebo. Inclusion decisions, assessment of study quality and data extraction were undertaken using methods to minimise bias. RESULTS: Fifty-three publications were included, reporting five RCTs (11 publications), 18 non-randomised comparisons (24 publications) and 18 publications that reported reviews, which added no further data. There was variation in the population, types and doses of ACT and APT, definitions of outcomes, and length of follow-up between the studies. There was a paucity of directly randomised high-quality RCTs, whereas non-randomised comparisons were found to have significant confounding factors. No studies looked at the effect of ACT plus APT compared with ACT alone on vascular events in patients with AF following acute coronary syndrome (ACS) or percutaneous coronary intervention. In most studies, significant differences in event rates were not seen between the patients on combined therapy compared with those on ACT alone for outcomes such as stroke (including haemorrhagic and ischaemic strokes), rates of transient ischaemic attacks, composite end points of stroke and systemic embolism (SE), SE alone, acute myocardial infarction, mortality (vascular or all cause) or bleeding events. There was conflicting evidence regarding rates of major adverse events consisting of composite end points, although event rates were generally low. LIMITATIONS: An attempt was made to identify all of the available evidence around the subject despite the dearth of directly randomised studies using a robust review methodology. There was a paucity of directly randomised evidence to undertake a meta-analysis for the merits of one technology over another. The selection criteria were kept necessarily broad with regard to the population, intervention and comparator in order to capture all relevant studies. CONCLUSIONS: This systematic review suggests that there is still insufficient evidence to advocate a clear benefit of the addition of APT to ACT compared with ACT alone in reducing the risk of vascular events in a population of patients at high risk of TEs resulting from AF. It is recommended that a definitive prospective RCT needs to be undertaken in a population at high risk of atherosclerotic coronary artery and other vascular events in addition to being at high risk of AF-mediated TEs. From the UK context, at the time of writing, any future trial should compare adjusted-dose warfarin [international normalised ratio (INR) 2.0-3.0] plus aspirin (75-325 mg) with adjusted-dose warfarin (INR 2.0-3.0). However, given the emergence of newer anticoagulation agents (dabigatran, rivaroxaban and apixaban) this prioritisation may need to be revisited in the future to reflect current best clinical practice. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Performance of stroke risk scores in older people with atrial fibrillation not taking warfarin: comparative cohort study from BAFTA trial.

OBJECTIVE: To compare the predictive power of the main existing and recently proposed schemes for stratification of risk of stroke in older patients with atrial fibrillation. DESIGN: Comparative cohort study of eight risk stratification scores. SETTING: Trial of thromboprophylaxis in stroke, the Birmingham Atrial Fibrillation in the Aged (BAFTA) trial. PARTICIPANTS: 665 patients aged 75 or over with atrial fibrillation based in the community who were randomised to the BAFTA trial and were not taking warfarin throughout or for part of the study period. MAIN OUTCOME MEASURES: Events rates of stroke and thromboembolism. RESULTS: 54 (8%) patients had an ischaemic stroke, four (0.6%) had a systemic embolism, and 13 (2%) had a transient ischaemic attack. The distribution of patients classified into the three risk categories (low, moderate, high) was similar across three of the risk stratification scores (revised CHADS(2), NICE, ACC/AHA/ESC), with most patients categorised as high risk (65-69%, n = 460-457) and the remaining classified as moderate risk. The original CHADS(2) (Congestive heart failure, Hypertension, Age ≥ 75 years, Diabetes, previous Stroke) score identified the lowest number as high risk (27%, n = 180). The incremental risk scores of CHADS(2), Rietbrock modified CHADS(2), and CHA(2)DS(2)-VASc (CHA(2)DS(2)-Vascular disease, Age 65-74 years, Sex) failed to show an increase in risk at the upper range of scores. The predictive accuracy was similar across the tested schemes with C statistic ranging from 0.55 (original CHADS(2)) to 0.62 (Rietbrock modified CHADS(2)), with all except the original CHADS(2) predicting better than chance. Bootstrapped paired comparisons provided no evidence of significant differences between the discriminatory ability of the schemes. CONCLUSIONS: Based on this single trial population, current risk stratification schemes in older people with atrial fibrillation have only limited ability to predict the risk of stroke. Given the systematic undertreatment of older people with anticoagulation, and the relative safety of warfarin versus aspirin in those aged over 70, there could be a pragmatic rationale for classifying all patients over 75 as "high risk" until better tools are available.

Quality assurance for oral anticoagulation self management: a cluster randomized trial.

BACKGROUND AND AIMS: External quality assessment (EQA) should be an inherent component of patient self management (PSM) of oral anticoagulation. The aim of this study was to evaluate methods of EQA for patients within a cluster randomized trial. METHOD: After development of methods, general practises were randomly allocated to a formal EQA scheme of patients performing the test independently at home or at their practise with supervision. The supervised group of practises was further sub divided to test two other EQA methods: (i) venous sample compared with patients' point of care (POC) device; and (ii) patients POC compared with reference POC. Primary trial outcome measure was reliability of results from the formal scheme taking into account adherence and test errors. RESULTS: Proportion of EQA scheme tests in range was 633/836 (75.7%). Proportion in range was significantly higher in group performing independently compared with supervised group, 80.1% vs. 71.5% respectively, P = 0.02. Sixty-six percent of tests were in range with venous compared with patients POC, and 88% in patients POC compared with reference POC. CONCLUSION: Patients are able to undertake a formal EQA scheme and perform more reliably at home independently. There are satisfactory alternatives if a formal scheme is not acceptable.

Patient self management of oral anticoagulation in routine care in the UK.

BACKGROUND: Self management of anticoagulation: a randomised trial (SMART) was the first large scale UK trial to assess clinical and cost effectiveness of patient self management (PSM) of oral anticoagulation therapy compared to routine care. SMART showed that while PSM was as clinically effective as routine care, it was not as cost effective. SMART adds to the growing body of trial data to support PSM; however there are no data on clinical effectiveness and cost of PSM in routine care. AIM: To evaluate clinical effectiveness of PSM compared to routine care outside trial conditions. METHODS: A retrospective multicentre matched control study. 63 PSM patients from primary care in the West Midlands were matched by age and international normalised ratio (INR) target with controls. INR results were collected for the period 1 July 2003-30 June 2004. The primary outcome measure was INR control. RESULTS: 38 PSM and 40 control patients were recruited. INR percentage time in range was 70% PSM vs 64% controls. 60% PSM were having a regular clinical review, 45% were performing an internal quality control (IQC) test and 82% were performing external quality assurance (EQA) on a regular basis. CONCLUSION: PSM outside trial conditions is as clinically effective as routine UK care.

Self management of oral anticoagulation: randomised trial.

OBJECTIVE: To determine the clinical effectiveness of self management compared with routine care in patients on long term oral anticoagulants. DESIGN: Multicentre open randomised controlled trial. SETTING: Midlands region of the UK. PARTICIPANTS: 617 patients aged over 18 and receiving warfarin randomised to intervention (n = 337) and routine care (n = from 2470 invited; 193/337 (57%) completed the 12 month intervention. INTERVENTION: Intervention patients used a point of care device to measure international normalised ratio twice a week and a simple dosing chart to interpret their dose of warfarin. MAIN OUTCOME MEASURE: Percentage of time spent within the therapeutic range of international normalised ratio. RESULTS: No significant differences were found in percentage of time in the therapeutic range between self management and routine care (70% v 68%). Self managed patients with poor control before the study showed an improvement in control that was not seen in the routine care group. Nine patients (2.8/100 patient years) had serious adverse events in the self managed group, compared with seven (2.7/100 patient years) in the routine care arm (chi2(df = 1) = 0.02, P = 0.89). CONCLUSION: With appropriate training, self management is safe and reliable for a sizeable proportion of patients receiving oral anticoagulation treatment. It may improve the time spent the therapeutic range for patients with initially poor control. Trial registration ISRCTN 19313375.

A randomised controlled trial and cost-effectiveness study of systematic screening (targeted and total population screening) versus routine practice for the detection of atrial fibrillation in people aged 65 and over. The SAFE study.

OBJECTIVES: To determine the most cost-effective method of screening for atrial fibrillation (AF) in the population aged 65 years and over, as well as its prevalence and incidence in this age group. Also to evaluate the relative cost-effectiveness of different methods of recording and interpreting the electrocardiogram (ECG) within a screening programme. DESIGN: Multicentred randomised controlled trial. Purposefully selected general practices were randomly allocated to 25 intervention practices and 25 control practices. SETTING: Fifty primary care centres across the West Midlands, UK. PARTICIPANTS: Patients aged 65 years and over. INTERVENTIONS: GPs and practice nurses in the intervention practices received education on the importance of AF detection and ECG interpretation. Patients in the intervention practices were randomly allocated to systematic (n = 5000) or opportunistic screening (n = 5000). Prospective identification of pre-existing risk factors for AF within the screened population enabled comparison between targeted screening of people at higher risk of AF and total population screening. MAIN OUTCOME MEASURES: AF detection rates in systematically screened and opportunistically screened populations in the intervention practices were compared with AF detection rate in 5000 patients in the control practices. The screening period was 12 months. RESULTS: Baseline prevalence of AF was 7.2%, with a higher prevalence in males (7.8%) and patients aged 75 years and over (10.3%). The control population demonstrated higher baseline prevalence (7.9%) than either the systematic (6.9%) or opportunistic (6.9%) intervention population. In the control population 47 new cases were detected (incidence 1.04% per year). In the opportunistic arm 243 patients without a baseline diagnosis of AF were found to have an irregular pulse, with 177 having an ECG, yielding 31 new cases (incidence 0.69% per year). A further 44 cases were detected outside the screening programme (overall incidence 1.64% per year). In the systematic arm 2357 patients had an ECG yielding 52 new cases (incidence 1.1% per year). Of these, 31 were detected by targeted screening and a further 21 by total population screening. A further 22 cases were detected outside the screening programme (overall incidence 1.62% per year). In terms of ECG interpretation, computerised decision support software (CDSS) gave a sensitivity of 87.3%, a specificity of 99.1% and a positive predictive value (PPV) of 89.5% compared with the gold standard (cardiologist reporting). GPs and practice nurses performed less well. The only difference in performance between intervention populations and controls was that practice nurses from the control arm performed less well than with intervention practice nurses on interpretation of limb-lead (PPV 38.8% versus 20.8%) and single-lead (PPV 37.7% versus 24.0%) ECGs. The within-trial economic evaluation results showed the lowest incremental cost to be for the opportunistic arm, with an incremental cost-effectiveness ratio of 337 pounds Sterling for each additional case detected compared to the control arm. Opportunistic screening dominated both more intensive screening strategies. Model-based analyses showed small differences in cost and quality-adjusted life-years for different methods and intensities of screening, but annual opportunistic screening resulted in the lowest number of ischaemic strokes and greatest proportion of cases of AF diagnosed. Probabilistic sensitivity results indicated that there was a probability of approximately 60% that screening from the age of 65 years was cost-effective in both men and women. CONCLUSIONS: The results of the study indicated that in terms of a screening programme for atrial fibrillation in patients 65 and over, the only strategy that improved on routine practice was opportunistic screening, model-based analyses indicated that there was a probability of approximately 60% of annual opportunistic screening being cost effective. It is suggested that the following topics are worthy of further investigation: the effect of the implementation of a screening programme for AF on the uptake and maintenance of anticoagulation in patients aged 65 years and over; an evaluation of the role of CDSS in the diagnosis of cardiac arrythmias; the best method for routinely detecting paroxysmal AF; ways of improving healthcare professionals' performance in ECG interpretation; development of a robust economic model to incorporate data on new therapeutic agents for use as thromboprophylactic agents for patients with AF, and an evaluation of the relative risk of stroke for patients with incident as opposed to prevalent AF.

An evidence-based review and guidelines for patient self-testing and management of oral anticoagulation.

There is a limited evidence base for self-testing and -management for oral anticoagulation management. Available data suggest that these are credible models for a significant minority of patients if underpinned by structured training and follow-up. The guidelines presented are necessarily consensual and outline procedures for patient selection, training, product procurement, product maintenance, quality assurance procedures, dosage adjustment and clinical supervision. The cost-effectiveness of these models remains to be elucidated within the UK. Further data on both health economic and clinical outcomes are required from UK based studies before widespread implementation of self-testing and management can be recommended on a wider scale.

Point of care testing for INR monitoring: where are we now?

Point of care (POC, or near patient) testing for measurement of the international normalized ratio (INR) has facilitated the devolution of service delivery from the traditional hospital outpatient setting. However it must be undertaken within the confines of safe practice involving quality control procedures. The evaluation of INR POC tests should be closely related to the clinical issues of management and, specifically, improving the quality of care. One benefit of POC testing is in the increased motivation that some practitioners feel, being able to perform diagnostic tests without sending samples to a laboratory. POC for INR testing within primary care eliminates the delay in waiting for the result to be processed by the hospital laboratory, and the subsequent delay in informing the patient of their dosing advice. This review describes the utilization of POC testing outside the laboratory setting to develop models of care for oral anticoagulation management.

Patient self-management of oral anticoagulation and external quality assessment procedures.

The role of external quality assessment (EQA) is a contentious issue for patient self-management (PSM) of oral anticoagulation. Patients from general practices in the West Midlands undertaking PSM were recruited to compare efficacy of patients' and health professionals' EQA procedure using the UK National External Quality Assessment Scheme (NEQAS). Patients using Coaguchek (Roche Diagnostics) were trained to perform EQA as part of their PSM training. They undertook PSM for 26 weeks and were asked to perform EQA using material provided by the UK NEQAS twice at home without supervision and twice at the practice with supervision. Patients' results were compared with health care professional users of Coaguchek S. Twenty-three PSM patients were compared with 75 health care professional users of the NEQAS scheme. The PSM group international normalized ratio (INR) percentage time in range was 74%. There was no significant difference in the median results on NEQAS samples obtained by the patients and those obtained by professionals. Three patients were outwith consensus (results > 15% from the median INR) on more than one occasion. Patients were able to perform the EQA tests competently. The data show that good agreement can be achieved between patients analysing the same EQA samples, with coefficients of variation ranging from 22.3% to as low as 5.4%. Further study is required to determine how precision within these EQA schemes relates to the stability of treatment in patients' management of their own anticoagulation.

External quality assessment for warfarin dosing using computerised decision support software.

AIM: To establish and evaluate an external quality assessment scheme for warfarin dosing for users of a computerised decision support system, BAP-PC. DESIGN: Analysis of 12 months of clinical data from 10 primary care centres using BAP-PC within an oral anticoagulation clinic. Data were analysed for individual centres and compared with aggregated data for all practices. Individual feedback forms were provided to participating centres. RESULTS: A total patient population of 367 (range, 17-65/centre) was analysed. On average, patients spent 69% of time in the therapeutic range (range, 60-76%). Patients were seen on average every 27 days (range, 24-30). The average point prevalence was 86% (range, 76-100%). In total, 33 adverse events were reported (0-13/practice). Serious adverse events ranged from 0 to 1 for each practice. This translates into a serious adverse event rate of 1.6/100 patient years. CONCLUSIONS: Practices were successful in maintaining good therapeutic international normalised ratio control, with centres achieving 60% or higher time in range. There are some doubts about the quality of data collection at a practice level because there were no reported events in half of the participating centres. The observed event rates do concur with previously reported data, however. Further cycles of the scheme are necessary to establish it as a useful research and benchmarking tool.

A systematic review of outcome measures reported for the therapeutic effectiveness of oral anticoagulation.

AIMS: To evaluate the evidence of therapeutic international normalised ratio (INR) control reporting and to provide recommendations for future reporting, particularly for research and audit purposes. METHODS: A systematic review of literature published over a five year period describing therapeutic INR control. Papers were identified from the Medline electronic database, and those that met the quality criteria were reviewed independently by an academic general practitioner and a consultant haematologist. RESULTS: Fifteen papers were identified that met the quality criteria for review. The sample size of studies ranged from 53 to 2545 (mean, 483.9) patients. Follow up ranged from three months to 13 years. Twelve studies reported results from secondary care only, one from primary care only, and two from both primary and secondary care. Seven of the 15 papers reported percentage time in range, five of 15 papers reported mean INR, six of 15 papers reported the proportion of tests in range, and five of 15 papers reported mean warfarin dose. Additional methods of presenting INR results were: dose changes each month, distribution of INR results, deviation of INR value from mean, percentage dose changes, time between visits, and median INR value. Six papers reported only one outcome measure, six reported two outcomes, two papers reported three outcomes, and one paper reported five outcomes. CONCLUSIONS: It is recommended that at least two outcome measures should be reported and measures should be selected so that both the INR determinations and dosing advice are monitored.

A randomised controlled trial of patient self management of oral anticoagulation treatment compared with primary care management.

BACKGROUND: The increase in numbers of patients receiving warfarin treatment has led to the development of alternative models of service delivery for oral anticoagulant monitoring. Patient self management for oral anticoagulation is a model new to the UK. This randomised trial was the first to compare routine primary care management of oral anticoagulation with patient self management. AIM: To test whether patient self management is as safe, in terms of clinical effectiveness, as primary care management within the UK, as assessed by therapeutic international normalised ratio (INR) control. METHOD: Patients receiving warfarin from six general practices who satisfied study entry criteria were eligible to enter the study. Eligible patients were randomised to either intervention (patient self management) or control (routine primary care management) for six months. The intervention comprised two training sessions of one to two hours duration. Patients were allowed to undertake patient self management on successful completion of training. INR testing was undertaken using a Coaguchek device and regular internal/external quality control tests were performed. Patients were advised to perform INR tests every two weeks, or weekly if a dose adjustment was made. Dosage adjustment was undertaken using a simple dosing algorithm. RESULTS: Seventy eight of 206 (38%) patients were eligible for inclusion and, of these, 35 (45%) declined involvement or withdrew from the study. Altogether, 23 intervention and 26 control patients entered the study. There were no significant differences in INR control (per cent time in range: intervention, 74%; control, 77%). There were no serious adverse events in the intervention group, with one fatal retroperitoneal haemorrhage in the control group. Costs of patient self management were significantly greater than for routine care (pound 90 v pound 425/patient/year). CONCLUSION: These are the first UK data to demonstrate that patient self management is as safe as primary care management for a selected population. Further studies are needed to elucidate whether this model of care is suitable for a larger population.

Does the Birmingham model of oral anticoagulation management in primary care work outside trial conditions?

The effectiveness of the Birmingham model of primary care oral anticoagulation management has previously been demonstrated within a randomised controlled trial. The aim of this study was to assess the effectiveness of the Birmingham model in routine care. All patients from 12 primary care centres attending either practice-based or hospital-based anticoagulation clinics were retrospectively followed up from October 1996 to March 1998. Outcome measures were therapeutic International Normalised Ratio (INR) control, haemorrhagic and thrombotic episodes, and recall frequency; 452 patients who had two or more INR results during the follow-up period were investigated. There were no significant differences between practice-based and hospital-based populations in terms of the percentage time in range, (69% and 64% respectively). The proportion of tests in range was significantly higher in the practice-based group (61% practice-based, 57% hospital-based; P = 0.015). There was no difference between the two populations in terms of mean follow-up time (36 days in each group). There were no significant differences between groups for the number of clinical outcomes per patient. This study confirmed that, within these practices, oral anticoagulation management is safe and effective using the Birmingham model.