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Background: Over 150 000 cases of suspected transient ischaemic attack (TIA) are referred to outpatient clinics in England each year. The majority of referrals are made by GPs.Aim: This study aimed to identify how many patients referred to a TIA clinic actually have TIA (that is, calculate the positive predictive value [PPV] of first-contact healthcare referral) and to record the alternative diagnoses in patients without TIA, in order to determine the optimal service model for patients with suspected TIA.Design and Setting: A systematic review of TIA clinic referrals from first-contact health professionals (GPs and emergency department [ED] doctors) was undertaken.Method: Four databases were searched using terms for TIA and diagnostic accuracy. Data on the number of patients referred to a TIA clinic who actually had a TIA (PPVs) were extracted. Frequencies of differential diagnoses were recorded, where reported. Study quality was assessed using the QUADAS-2 tool.Results: Nineteen studies were included and reported sufficient information on referrals from GPs and ED doctors to derive PPVs (n = 15 935 referrals). PPVs for TIA ranged from 12.9% to 72.5%. A formal meta-analysis was not conducted due to heterogeneity across studies. Of those not diagnosed with TIA, approximately half of the final diagnoses were of neurological or cardiovascular conditions.Conclusion: This study highlights the variation in prevalence of true vascular events in patients referred to TIA clinics. For patients without a cerebrovascular diagnosis, the high prevalence of conditions that also require specialist investigations and management are an additional burden on a care pathway that is primarily designed to prevent recurrent stroke. Service commissioners need to assess whether the existing outpatient provision is optimal for people with pathologies other than cerebrovascular disease. [ABSTRACT FROM AUTHOR]

Background: Creatinine-based estimated glomerular filtration rate (eGFR) determines chronic kidney disease (CKD) stage, but underestimates renal function. The 2014 updated guidance from the National Institute for Health and Care Excellence (NICE) recommends that GPs reduce overdiagnosis of CKD stage 3a (eGFR 45-60 ml/min/1.73 m2) by using the renal biomarker cystatin C.Aim: To determine the population requirement for cystatin C testing, compared with current national availability of the assay.Design and Setting: Retrospective study of primary care laboratory requests in Oxfordshire, England.Method: The first creatinine results from tests ordered in primary care over a 6-year period (2008-2014) in a population of 600 000 in Oxfordshire were analysed and the number of patients with CKD stage 3a without proteinuria (who, in accordance with NICE guidance, required cystatin C) was determined. A conservative estimate of the national need was provided by scaling the population of Oxfordshire to the national population (CKD prevalence in the county is below the national average). Cystatin C assay availability was determined using national databases of laboratory assay provision.Results: From a population of 600 000, there were 22 240 individuals with stable stage 3a CKD and no proteinuria. As the population of Oxfordshire equates to 1% of the UK population, there is an initial requirement for at least 2 million people to have their CKD status determined with cystatin C testing. Eight laboratories (2.1% of UK laboratories) reported cystatin C assay provision.Conclusion: There is a substantial gap between cystatin C assay requirements in primary care and national assay provision. This is a major barrier to implementing NICE guidance. [ABSTRACT FROM AUTHOR]

Background: Pertussis (whooping cough) is a highly infective cause of cough that causes significant morbidity and mortality. Existing case definitions include paroxysmal cough, whooping, and posttussive vomiting, but diagnosis can be difficult. We determined the diagnostic accuracy of clinical characteristics of pertussis-associated cough.Methods: We systematically searched CINAHL, Embase, Medline, and SCI-EXPANDED/CPCI-S up to June 2016. Eligible studies compared clinical characteristics in those positive and negative for Bordetella pertussis infection, confirmed by laboratory investigations. Two authors independently completed screening, data extraction, and quality and bias assessments. For each characteristic, RevMan was used to produce descriptive forest plots. The bivariate meta-analysis method was used to generate pooled estimates of sensitivity and specificity.Results: Of 1,969 identified papers, 53 were included. Forty-one clinical characteristics were assessed for diagnostic accuracy. In adult patients, paroxysmal cough and absence of fever have a high sensitivity (93.2% [CI, 83.2-97.4] and 81.8% [CI, 72.2-88.7], respectively) and low specificity (20.6% [CI, 14.7-28.1] and 18.8% [CI, 8.1-37.9]), whereas posttussive vomiting and whooping have low sensitivity (32.5% [CI, 24.5-41.6] and 29.8% [CI, 8.0-45.2]) and high specificity (77.7% [CI, 73.1-81.7] and 79.5% [CI, 69.4-86.9]). Posttussive vomiting in children is moderately sensitive (60.0% [CI, 40.3-77.0]) and specific (66.0% [CI, 52.5-77.3]).Conclusions: In adult patients, the presence of whooping or posttussive vomiting should rule in a possible diagnosis of pertussis, whereas the lack of a paroxysmal cough or the presence of fever should rule it out. In children, posttussive vomiting is much less helpful as a clinical diagnostic test. [ABSTRACT FROM AUTHOR]

Background: Chronic kidney disease (CKD) is a major risk factor for cardiovascular disease (CVD) and European guidelines advocate assessment of CVD risk. QRISK and JBS3 risk calculators do not use the consensus definition of CKD stages 3-5 but instead use a definition referring to renal pathologies and CKD stages 4 and 5. Consequently, there is potential for doctors to misclassify their patients when using these risk calculators.Objectives: To quantify the number of people who may be affected by such misclassifications.Methods: Database analysis using the Clinical Practice Research Datalink (CPRD).We identified 2512053 adults aged 25-84 without prior history of CVD on 1st January 2014. We identified those with 'chronic renal disease' and/or CKD by searching medical event history data.Results: The study population was 48.7% male with mean age of 50.2 years. A total of 80718 had diagnostic READ codes for CKD stages 3, 4 or 5. Of these, 6585 individuals (8.2%) were classified as having 'chronic renal disease' according to the updated QRISK 2014, up from 3365 according to QRISK 2013. Whilst the updated QRISK definition of 'chronic renal disease' in total identified 62% more people than previously and had improved sensitivity for CKD stages 3 to 5, sensitivity remained poor (8.16%; 95% CI: 7.97-8.35%).Conclusion: Misuse of risk scores by general practitioners could result in clinically important differences in risk estimates. Users of risk scores should recognize the potential for error and developers should aim to label risk factors more clearly. [ABSTRACT FROM AUTHOR]

Background In spite of public education campaigns, patients with transient ischemic attack still present to primary care where accurate recognition of transient ischemic attack is essential so that specialist referral can be expedited to reduce stroke risk. The complex task of diagnosing transient ischemic attack is challenging in time-limited settings in primary care yet the potential for a transient ischemic attack recognition tool to improve diagnosis has not been determined. Aims We set out to examine the potential utility in primary care of the only existing transient ischemic attack recognition tool. Methods All primary care referrals with suspected transient ischemic attack from a total population of 91 000 people were analyzed over a four-year period from 2002 to 2006. Clinical and research records from the transient ischemic attack clinic and consultation notes and referral letters from primary care physicians were used to populate the Dawson recognition score. Results Of 513 referrals, 209 (47%) had a clinic confirmed diagnosis of transient ischemic attack. Agreement between primary care assessments and specialist assessments was greater for speech disturbance (kappa 0·68) than for unilateral facial weakness (0·58) and unilateral limb weakness (0·51). The Dawson score had greater accuracy in diagnosing all transient ischemic attack in specialist assessments than in primary care assessments (c statistics 0·80 vs. 0·70, P < 0·0001) and performed particularly poorly in primary care for detecting posterior circulation territory transient ischemic attack with a c statistic (95% confidence interval) of 0·52 (0·43-0·61). Conclusion The Dawson transient ischemic attack recognition score is less accurate in primary care than in its derivation setting of specialist care. Improving the recognition of transient ischemic attack by providers of first contact health care requires derivation of rules in the clinical setting in which they are to be used. [ABSTRACT FROM AUTHOR]

This is an overview of the principles that underpin philosophy of science and how they may provide a framework for the diagnostic process. Although philosophy dates back to antiquity, it is only more recently that philosophers have begun to enunciate the scientific method. Since Aristotle formulated deduction, other modes of reasoning including induction, inference to best explanation, falsificationism, theory-laden observations and Bayesian inference have emerged. Thus, rather than representing a single overriding dogma, the scientific method is a toolkit of ideas and principles of reasoning. Here we demonstrate that the diagnostic process is an example of science in action and is therefore subject to the principles encompassed by the scientific method. Although a number of the different forms of reasoning are used readily by clinicians in practice, without a clear understanding of their pitfalls and the assumptions on which they are based, it leaves doctors open to diagnostic error. We conclude by providing a case example from the medico-legal literature in which diagnostic errors were made, to illustrate how applying the scientific method may mitigate the chance for diagnostic error. [ABSTRACT FROM AUTHOR]

Background: Serious infections in older people are associated with unplanned hospital admissions and high mortality. Recognising the presence of a serious infection and making an accurate diagnosis are important challenges for General Practice. This study aimed to explore the issues UK GPs face when diagnosing serious infections in older patients. Methods: Qualitative study using semi-structured interviews. 28 GPs from 27 practices were purposively sampled from across the UK to achieve maximum variation in terms of GP role, experience and practice population. Interviews began by asking participants to describe recent or memorable cases where they had assessed older patients with suspected serious infections. Additional questions from the topic guide were used to explore the challenges further. Interview transcripts were coded and analysed using a modified framework approach. Results: Diagnosing serious infection in older adults was perceived to be challenging by participating GPs and the diagnosis was often uncertain. Contributing factors included patient complexity, atypical presentations, as well as a lack of knowledge of patients due to a loss in continuity. Diagnostic challenges were present at each stage of the patient assessment. Scoring systems were mainly used as communication tools. Investigations were sometimes used to resolve diagnostic uncertainty, but availability and speed of result limited their practical use. Clear safety-net plans shared with patients and their families helped GPs manage ongoing uncertainty. Conclusions: Diagnostic challenges are present throughout the assessment of an older adult with a serious infection in primary care. Supporting GPs to provide continuity of care may improve the recognition and developing point of care testing for use in community settings may reduce diagnostic uncertainty. [ABSTRACT FROM AUTHOR]