F. D. R. Hobbs

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 (£90 v £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.

A primary care evaluation of three near patient coagulometers.

AIM: To compare the reliability and relative costs of three international normalised ratio (INR) near patient tests. MATERIALS: Protime (ITC Technidyne), Coaguchek (Boehringer Mannheim), and TAS (Diagnostic Testing). METHODS: All patients attending one inner city general practice anticoagulation clinic were asked to participate, with two samples provided by patients not taking warfarin. A 5 ml sample of venous whole blood was taken from each patient and a drop immediately added to the prepared Coaguchek test strip followed by the Protime cuvette. The remainder was added to a citrated bottle. A drop of citrated blood was then placed on the TAS test card and the remainder sent to the reference laboratory for analysis. Parallel INR estimation was performed on the different near patient tests at each weekly anticoagulation clinic from July to December 1997. RESULTS: 19 patients receiving long term warfarin treatment provided 62 INR results. INR results ranged from 0.8-8.2 overall and 1.0-5.7 based on the laboratory method. Taking the laboratory method as the gold standard, 12/62 results were < 2.0 and 2/62 were > 4.5. There were no statistical or clinically significant differences between results from the three systems, although all near patient tests showed slightly higher mean readings than the laboratory, and 19-24% of tests would have resulted in different management decisions based on the machine used in comparison with the laboratory INR value. The cost of the near patient test systems varied substantially. CONCLUSIONS: All three near patient test systems are safe and efficient for producing acceptable and reproducible INR results within the therapeutic range in a primary care setting. All the systems were, however, subject to operator dependent variables at the time of blood letting. Adequate training in capillary blood sampling, specific use of the machines, and quality assurance procedures is therefore essential.

Left ventricular ejection fraction: are the revised cut-off points for defining systolic dysfunction sufficiently evidence based?

The recent guidelines from the American Society of Echocardiography and European Society of Echocardiography have defined an abnormal ejection fraction (EF) of the left ventricle, as one that is <55%.1 Owing to the fact that it is a continuous biological variable, there is inevitable debate over what constitutes mild, moderate and severe left ventricular (LV) dysfunction across the ranges of EF. Up to now, the lower limit of normal in clinical practice has usually been set at 40%.2 Despite the recent guidelines,1 there has been little debate or evidence to suggest altering the lower limit of normality to include patients with EFs of 50–54%. These guidelines therefore represent a step change in the definition of (echocardiographic) LV systolic dysfunction and will include many more patients into the category of “impaired LV function” with EFs >50%. The main limitation of this approach is how best to define risk. The cut-off points suggested for a single parameter can vary broadly for the risk of death, myocardial infarction, congestive heart failure and atrial fibrillation. Also, much of the literature applies to specific populations (eg, after myocardial infarction, the elderly) and not to overall cardiovascular risk.1 The recommended new cut-off EF value of 54% is based on expert opinion, interpreting data from the limited number of studies that have reported that an EF <54% is associated with moderate adverse outcomes.1 For example, Roman et al followed up 486 patients undergoing echocardiography to determine the prevalence of carotid atherosclerosis and to examine its relationship to LV hypertrophy.3 Two hundred and seventy-seven subjects were normotensive and 209 subjects had untreated hypertension, and all were asymptomatic with no overt manifestations of cerebrovascular disease. The investigators found that 392 patients were essentially without any evidence of carotid plaques and 366 patients had …

The scale of heart failure: diagnosis and management issues for primary care

Heart failure is a significant public health issue. Epidemiological surveys using clinical findings suggest that between 1–2% of western adult populations are affected by heart failure. More recent data, however, based on objective cardiac assessment, suggest that 2% is the more accurate figure.1 2 Further evidence from the US show that in the last 20 years there has been a fourfold increase in unadjusted mortality rates for heart failure (fig 1). The most obvious reason for this is the increase in the aging population, although changes in classification may be another factor. Prevalence is also increasing because more people are surviving myocardial infarcts (fig 2). There is an inexorable relation between patients surviving an acute myocardial infarction and the subsequent development of heart failure. Therefore, if the number of patients surviving acute myocardial infarction increase, it is almost certain that an increasing heart failure prevalence will follow. Figure 1 Increasing prevalence of heart failure. Figure 2 Risk of heart failure following myocardial infarction. There are three issues to consider in terms of the impact of heart failure. Mortality is related to disease severity, so prognosis is determined by stage of heart failure. Looking at heart failure overall, the five year mortality rate of 50% is analogous to that of many cancers. The prognosis for moderate and severe heart failure is almost identical to colorectal cancer3 and worse than breast4 or prostatic cancer,5 which develop at a similar age to heart failure (table 1). Interestingly, the impact of breast cancer is considered sufficiently significant to warrant a national screening programme for women from the age of 50 years. In the US there are also formal screening programmes for prostatic cancer. View this table: Table 1 Survival rates compared with heart failure3–5 The second issue relates to high health care costs, largely related to the use …

Acquisition of basic clinical skills in the general practice setting

Undergraduate medical education in the UK is changing due to both educational pressure (from the General Medical Council) and changes in the hospital service. As a result the role of general practice in providing core clinical experience is under debate. The purpose of this study was to determine the clinical contact available for junior clinical medical clerks (third year) attached to five general practices.

A meta-analysis of echocardiographic measurements of the left heart for the development of normative reference ranges in a large international cohort : the EchoNoRMAL study

AIM To develop age-, sex-, and ethnic-appropriate normative reference ranges for standard echocardiographic measurements of the left heart by combining echocardiographic measurements obtained from adult volunteers without clinical cardiovascular disease or significant cardiovascular risk factors, from multiple studies around the world. METHODS AND RESULTS The Echocardiographic Normal Ranges Meta-Analysis of the Left heart (EchoNoRMAL) collaboration was established and population-based data sets of echocardiographic measurements combined to perform an individual person data meta-analysis. Data from 43 studies were received, representing 51 222 subjects, of which 22 404 adults aged 18-80 years were without clinical cardiovascular or renal disease, hypertension or diabetes. Quantile regression or an appropriate parametric regression method will be used to derive reference values at the 5th and 95th centile of each measurement against age. CONCLUSION This unique data set represents a large, multi-ethnic cohort of subjects resident in a wide range of countries. The resultant reference ranges will have wide applicability for normative data based on age, sex, and ethnicity.

Imprecision in medical communication: study of a doctor talking to patients with serious illness.

Uncertainty is believed to be a central feature in illness experiences. Conversations between a consultant haematologist and 61 seriously ill patients were transcribed, entered on a database and scrutinized for patterns of language uncertainty by linguistic concordancing analysis. Transcripts were then discussed in detail with the haematologist, and techniques of protocol analysis were used to gain insight into his thought processes during consultations. The main findings were that the doctor used many more expressions of uncertainty than did patients: that evaluative terms were widely used to reassure rather than to worry patients; and that patients and doctor together used certain key terms ambiguously, in a manner which allowed the doctor to feel that facts were not misrepresented while perhaps permitting the patient to feel reassured.

Primary prevention of cardiovascular disease: managing hypertension and hyperlipidaemia.

Cardiovascular medicine has a sound evidence base upon which health professionals can base their interventions to modify risk among the British public. For primary prevention of cardiovascular disease, however, while there is considerable evidence on what to do, data are limited on how the evidence should be implemented in practice. The challenge will be to learn by experience which interventions directed at reducing blood pressure and lipids levels work best in different settings. There is a need to structure care to identify individuals who are at risk. Current targets are explicit and achievable for both hypertension and lipids. Effective treatment is likely to require multiple drug treatment.

Modern management of hypertension and heart failure: evidence and practice

Data on the clinical effectiveness of treatments for hypertension and heart failure are particularly extensive. This should result in the management of these conditions being among the most evidence based in medicine. However, as in many areas of medicine, a significant gap persists between the availability of evidence on effectiveness and the modification of routine clinical practice. This gap between evidence and practice is particularly important in the management of cardiovascular disease since coronary heart disease and stroke have become the two principal global causes of death and disability.1 The relation between rising blood pressure and cardiovascular mortality is well known. The closer relation between systolic pressure and risk of cardiac events, however, is still underestimated. There is a fivefold increase in cardiovascular risk at high systolic pressures compared to the threefold increase with high diastolic pressure.2 It is still the case that many physicians concentrate principally on lowering diastolic pressure while not achieving systolic blood pressure targets. This problem is further highlighted by the introduction of newer more aggressive blood pressure thresholds for diagnosis and targets for treatment. With these new thresholds, up to one third of the adult population in some countries would qualify as suffering hypertension. Treating hypertension reduces the risk of cardiovascular mortality and morbidity. However, the scale of risk reductions possible in stroke prevention are reduced in the prevention of coronary heart disease.3 Another group that has been under treated on a systematic basis are the elderly. As their absolute risk of events is much greater, the benefits to patients and to society would be much larger if they were more effectively treated. ### CURRENT PRACTICE IN HYPERTENSION Data from the USA shows that there has been an improvement from the mid 1970s to the early 1990s in the number of hypertensive patients detected. However, there is …

A comparison of international normalised ratio (INR) measurement in hospital and general practice settings: evidence for lack of standardisation

Previous reports of discrepancies in international normalised ratio (INR) measurement between centres have focused on hospital based methodologies.1–3 Previously, we have demonstrated differences in derived INR values for the same sample tested in primary care and in one of three different haematology laboratories.4 Our present study is an extension of the previous one, investigating comparative results based on contemporaneous samples measured in one primary care centre and in two hospital laboratories using a variety of techniques. Venous blood was drawn from patients in one primary care centre over a three month …