Distributed cognition: Theoretical insights and practical applications to health professions education: AMEE Guide No. 159.

Distributed cognition (DCog) is a member of the family of situativity theories that widens the lens of cognition from occurring solely inside the head to being socially, materially and temporally distributed within a dynamic system. The concept of extending the view of cognition to outside the head of a single health professional is relatively new in the healthcare system. DCog has been increasingly used by researchers to describe many ways in which health professionals perform in teams within structured clinical environments to deliver healthcare for patients. In this Guide, we expound ten central tenets of the macro (grand) theory of DCog (1. Cognition is decentralized in a system; 2. The unit of analysis is the system; 3. Cognitive processes are distributed; 4. Cognitive processes emerge from interactions; 5. Cognitive processes are interdependent; 6. Social organization is a cognitive architecture; 7. Division of labour; 8. Social organization is a system of communication; 9. Buffering and filtering; 10. Cognitive processes are encultured) to provide theoretical insights as well as practical applications to the field of health professions education.

Sharing the Bandwidth in Cognitively Overloaded Teams and Systems: Mechanistic Insights from a Walk on the Wild Side of Clinical Reasoning.

IssuePrevious work from the diagnostic error literature has provided indirect evidence that faulty clinical reasoning may be the most frequent cause of error when attaching a diagnostic label. The precise mechanisms underlying diagnostic error are unclear and continue to be subject to considerable theory informed debate in the clinical reasoning literature. Evidence: We take a theoretical approach to merging these two worlds of literature by first zooming out using distributed cognition as a social cognitive lens (macro theory) to develop a view of the process and outcome of clinical reasoning occurring in the wild - defined as the integrated clinical workplace - the natural habitat of clinicians working within teams. We then zoom in using the novel combination of cognitive load theory and distributed cognition to provide additional theoretical insights into the potential mechanisms of error. Implications: Through the lenses of distributed cognition and cognitive load theory, we can begin to prospectively investigate how cognitive overload is represented and shared within interprofessional teams over time and space and how this influences clinical reasoning performance and leads to error. We believe that this work will help teams manage cognitive load and prevent error.

Gaining an advantage by sitting an OSCE after your peers: A retrospective study.

Purpose: To investigate if final year medical students undertaking an OSCE station at a later stage during examination diet were advantaged over their peers who undertook the same station at an earlier stage, and whether any such effect varies by the student's relative academic standing. Methods: OSCE data from six consecutive final year cohorts totaling 1505 students was analyzed. Mixed effects logistic regression was used to model factors associated with the probability of passing each individual station (random effects for students and circuits; and fixed effects to assess the association with day of examination, time of day, gender and year). Results: Weaker students were more likely to pass if they took their OSCE later in the examination period. The odds of passing a station increased daily by 20%. Overall, the mean number of stations passed by each student increased over the 5 days. Conclusions: Students undertaking the same OSCE stations later in examination period statistically had higher chances of passing compared to their peers, and the weaker students appear to be particularly advantaged. These findings have major implications for OSCE design, to ensure students are not advantaged by examination timing, and weaker students are not "passing in error".

Randomized trial of switching from prescribed non-selective non-steroidal anti-inflammatory drugs to prescribed celecoxib: the Standard care vs. Celecoxib Outcome Trial (SCOT).

BACKGROUND: Selective cyclooxygenase-2 inhibitors and conventional non-selective non-steroidal anti-inflammatory drugs (nsNSAIDs) have been associated with adverse cardiovascular (CV) effects. We compared the CV safety of switching to celecoxib vs. continuing nsNSAID therapy in a European setting. METHOD: Patients aged 60 years and over with osteoarthritis or rheumatoid arthritis, free from established CV disease and taking chronic prescribed nsNSAIDs, were randomized to switch to celecoxib or to continue their previous nsNSAID. The primary endpoint was hospitalization for non-fatal myocardial infarction or other biomarker positive acute coronary syndrome, non-fatal stroke or CV death analysed using a Cox model with a pre-specified non-inferiority limit of 1.4 for the hazard ratio (HR). RESULTS: In total, 7297 participants were randomized. During a median 3-year follow-up, fewer subjects than expected developed an on-treatment (OT) primary CV event and the rate was similar for celecoxib, 0.95 per 100 patient-years, and nsNSAIDs, 0.86 per 100 patient-years (HR = 1.12, 95% confidence interval, 0.81-1.55; P = 0.50). Comparable intention-to-treat (ITT) rates were 1.14 per 100 patient-years with celecoxib and 1.10 per 100 patient-years with nsNSAIDs (HR = 1.04; 95% confidence interval, 0.81-1.33; P = 0.75). Pre-specified non-inferiority was achieved in the ITT analysis. The upper bound of the 95% confidence limit for the absolute increase in OT risk associated with celecoxib treatment was two primary events per 1000 patient-years exposure. There were only 15 adjudicated secondary upper gastrointestinal complication endpoints (0.078/100 patient-years on celecoxib vs. 0.053 on nsNSAIDs OT, 0.078 vs. 0.053 ITT). More gastrointestinal serious adverse reactions and haematological adverse reactions were reported on nsNSAIDs than celecoxib, but more patients withdrew from celecoxib than nsNSAIDs (50.9% patients vs. 30.2%; P < 0.0001). INTERPRETATION: In subjects 60 years and over, free from CV disease and taking prescribed chronic nsNSAIDs, CV events were infrequent and similar on celecoxib and nsNSAIDs. There was no advantage of a strategy of switching prescribed nsNSAIDs to prescribed celecoxib. This study excluded an increased risk of the primary endpoint of more than two events per 1000 patient-years associated with switching to prescribed celecoxib. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/show/NCT00447759; Unique identifier: NCT00447759.

Cognitive Impairment and Heart Failure: Systematic Review and Meta-Analysis.

BACKGROUND: Cognitive impairment and dementia are associated with a range of cardiovascular conditions, including hypertension, coronary artery disease, and atrial fibrillation. We aimed to describe the association with heart failure, summarizing published data to give estimates of prevalence, incidence, and relative risk of cognitive impairment/dementia in heart failure. METHODS: We searched multidisciplinary databases including MEDLINE (OVID), EMBASE (OVID), CINAHL (EBSCO), PsychINFO (EBSCO), Web of Science (Thomson Reuters), and CENTRAL (Cochrane Library) from inception until May 31, 2015. All relevant studies looking at cognitive impairment/dementia in heart failure were included. Studies were selected by 2 independent reviewers using prespecified inclusion/exclusion criteria. Where data allowed, we performed meta-analysis and pooled results using random effects models. RESULTS: From 18,000 titles, 37 studies were eligible (n = 8411 participants). Data from 4 prospective cohorts (n = 2513 participants) suggest greater cognitive decline in heart failure compared with non-heart failure over the longer term. These data were not suitable for meta-analysis. In case control studies describing those with and without heart failure (n = 4 papers, 1414 participants) the odds ratio for cognitive impairment in the heart failure population was 1.67 (95% confidence interval 1.15-2.42). Prevalence of cognitive impairment in heart failure cohorts (n = 26 studies, 4176 participants) was 43% (95% confidence interval 30-55). CONCLUSIONS: This review suggests a substantial proportion of patients with heart failure have concomitant cognitive problems. This has implications for planning treatment and services. These data do not allow us to comment on causation, and further work is needed to describe the underlying pathophysiology.

Genome-Wide Association Analysis of Young-Onset Stroke Identifies a Locus on Chromosome 10q25 Near HABP2.

BACKGROUND AND PURPOSE: Although a genetic contribution to ischemic stroke is well recognized, only a handful of stroke loci have been identified by large-scale genetic association studies to date. Hypothesizing that genetic effects might be stronger for early- versus late-onset stroke, we conducted a 2-stage meta-analysis of genome-wide association studies, focusing on stroke cases with an age of onset <60 years. METHODS: The discovery stage of our genome-wide association studies included 4505 cases and 21 968 controls of European, South-Asian, and African ancestry, drawn from 6 studies. In Stage 2, we selected the lead genetic variants at loci with association P<5×10(-6) and performed in silico association analyses in an independent sample of ≤1003 cases and 7745 controls. RESULTS: One stroke susceptibility locus at 10q25 reached genome-wide significance in the combined analysis of all samples from the discovery and follow-up stages (rs11196288; odds ratio =1.41; P=9.5×10(-9)). The associated locus is in an intergenic region between TCF7L2 and HABP2. In a further analysis in an independent sample, we found that 2 single nucleotide polymorphisms in high linkage disequilibrium with rs11196288 were significantly associated with total plasma factor VII-activating protease levels, a product of HABP2. CONCLUSIONS: HABP2, which encodes an extracellular serine protease involved in coagulation, fibrinolysis, and inflammatory pathways, may be a genetic susceptibility locus for early-onset stroke.

Impact of treatment algorithms on the prescribing of antithrombotic therapy in patients with suspected acute coronary syndrome - a prospective audit.

AIMS: Chest pain presentations are common although most patients do not have an acute coronary syndrome (ACS). We hypothesized that our local therapeutic guideline was leading to many low risk patients being inappropriately treated with potent anti-thrombotic therapy for ACS. METHODS: We conducted a prospective analysis of patients presenting with suspected ACS to the Western Infirmary Glasgow over a 2 month period between 6/10/13-3/11/13 and 5/4/14-2/5/14. We collated data on demographics, investigation, initial management and final diagnosis. Patients taking warfarin were excluded. We calculated sensitivity, specificity and receiver operating characteristic (ROC) curves for our local guideline, the SIGN guideline and a new guideline proposal. RESULTS: We studied 202 patients of whom 112 (55%) were male with mean (SD) age 60 (15) years. Full anti-thrombotic therapy for ACS was recommended in 91 patients (45%) according to the NHS GG&C guideline, 37 (18%) by the SIGN guideline and 30 (15%) by our new guideline proposal. The final diagnosis was ACS in 39 patients (19%). The current NHS GG&C guideline had a sensitivity of 80%, specificity 63% and AUROC 0.71 (95% CI 0.63, 0.80). The respective values were 62%, 92% and 0.77 (95% CI 0.67, 0.86) for the SIGN guideline and 54%, 94% and 0.74 (95% CI 0.64, 0.84) for our new proposed guideline. CONCLUSIONS: Only one-fifth of patients who present with chest pain or suspected ACS have ACS as their final diagnosis. Our new guideline proposal is highly specific and would minimize unnecessary administration of potent anti-thrombotic therapy to low risk patients.

Guidelines for the prevention of stroke in women: a statement for healthcare professionals from the American Heart Association/American Stroke Association.

PURPOSE: The aim of this statement is to summarize data on stroke risk factors that are unique to and more common in women than men and to expand on the data provided in prior stroke guidelines and cardiovascular prevention guidelines for women. This guideline focuses on the risk factors unique to women, such as reproductive factors, and those that are more common in women, including migraine with aura, obesity, metabolic syndrome, and atrial fibrillation. METHODS: Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council's Scientific Statement Oversight Committee and the AHA's Manuscript Oversight Committee. The panel reviewed relevant articles on adults using computerized searches of the medical literature through May 15, 2013. The evidence is organized within the context of the AHA framework and is classified according to the joint AHA/American College of Cardiology and supplementary AHA Stroke Council methods of classifying the level of certainty and the class and level of evidence. The document underwent extensive AHA internal peer review, Stroke Council Leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the AHA Science Advisory and Coordinating Committee. RESULTS: We provide current evidence, research gaps, and recommendations on risk of stroke related to preeclampsia, oral contraceptives, menopause, and hormone replacement, as well as those risk factors more common in women, such as obesity/metabolic syndrome, atrial fibrillation, and migraine with aura. CONCLUSIONS: To more accurately reflect the risk of stroke in women across the lifespan, as well as the clear gaps in current risk scores, we believe a female-specific stroke risk score is warranted.

Depression and anxiety symptoms post-stroke/TIA: prevalence and associations in cross-sectional data from a regional stroke registry.

BACKGROUND: Mood disorders are commonly seen in those with cerebrovascular disease. Literature to-date has tended to focus on depression and on patients with stroke, with relatively little known about post-stroke anxiety or mood disorder in those with transient ischaemic attack (TIA). We aimed to describe prevalence of depression and anxiety symptoms in stroke and TIA cohorts and to explore association with clinical and socio-demographic factors. METHODS: We used a city wide primary care stroke registry (Glasgow Local Enhanced Service for Stroke - LES). All community dwelling stroke-survivors were included. We described cross-sectional prevalence of depression and anxiety symptoms using the Hospital Anxiety and Depression Scale (HADS). Data on clinical and demographic details was collected and univariable and multivariable analyses performed to describe associations with HADS scores. We examined those with a diagnosis of 'stroke' and 'TIA' as separate cohorts. RESULTS: From 13,283 potentially eligible stroke patients in the registry, we had full HADS data on 4,079. Of the 3,584 potentially eligible TIA patients, we had full HADS data on 1,247 patients. Across the stroke cohort, 1181 (29%) had HADS anxiety scores suggestive of probable or possible anxiety; 993 (24%) for depression. For TIA patients, 361 (29%) had anxiety and 254 (21%) had depression. Independent predictors of both depression and anxiety symptoms were female sex, younger age and higher socioeconomic deprivation score (all p < 0.001). CONCLUSION: Using HADS, we found a high prevalence of anxiety and depression symptoms in a community-based cohort of patients with cerebrovascular disease.

A randomised crossover trial of the acute effects of a deep-fried Mars bar or porridge on the cerebral vasculature.

INTRODUCTION: The deep-fried Mars bar has been cited as 'all that is wrong with the high-fat, high-sugar Scottish diet'. We investigated the effect of ingestion of a deep-fried Mars bar or porridge on cerebrovascular reactivity. We hypothesised that deep-fried Mars bar ingestion would impair cerebrovascular reactivity, which is associated with increased risk of ischaemic stroke. METHODS: Twenty-four fasted volunteers were randomised to receive a deep-fried Mars bar and then porridge (control), or vice-versa. We used transcranial Doppler ultrasound to calculate Breath Holding Index as a surrogate measure of cerebrovascular reactivity. Change in Breath Holding Index post-ingestion was the primary outcome measure. RESULTS: Twenty-four healthy adults (mean (SD) age 21.5 (1.7) years, 14 males) completed the protocol. Deep-fried Mars bar ingestion caused a non-significant reduction in cerebrovascular reactivity relative to control (mean difference in absolute Breath Holding Index after deep-fried Mars bar versus porridge -0.11, p = 0.40). Comparison of the difference between the absolute change in Breath Holding Index between genders demonstrated a significant impairment of cerebrovascular reactivity in males (mean difference women minus men of 0.65, 95% CI 0.30 to 1.00, p = 0.0003). CONCLUSION: Ingestion of a bolus of sugar and fat caused no overall difference in cerebrovascular reactivity, but there was a modest decrease in males. Impaired cerebrovascular reactivity is associated with increased stroke risk, and therefore deep-fried Mars bar ingestion may acutely contribute to cerebral hypoperfusion in men.

Use of mHealth in promoting maternal and child health in "BIMARU" states of India "A health system strengthening strategy": Systematic literature review.

Low-middle income countries like India bear a heavier burden of maternal, childcare, and child mortality rates when compared with high-income countries, which highlights the disparity in global health. Numerous societal, geopolitical, economic, and institutional issues have been linked to this inequality. mHealth has the potential to ameliorate these challenges by providing health services and health-related information with the assistance of frontline workers in the provision of prepartum, delivery, and postnatal care to improve maternal and child health outcomes in hard-to-reach areas in low- and middle-income countries (LMICs). However, there is limited evidence to support how mHealth can strengthen maternal and child health in India. The scoping review guideline in the Cochrane Handbook was used to retrieve studies from 4 international databases: CINAHL, Embase, Medline Ovid, and PubMed. This search strategy used combined keywords (MeSH terms) related to maternal and child healthcare, mHealth, and BIMARU in conjunction with database-controlled vocabulary. Out of 278 records, 8 publications were included in the review. The included articles used mHealth for data collection, eLearning, communication, patient monitoring, or tracking to deliver maternal and neonatal care. The results of these papers reflected a favourable effect of mHealth on the target population and found that it altered their attitudes and behaviours about healthcare. Higher job satisfaction and self-efficiency were reported by mHealth user care providers. Multiple barriers to the acceptance of mHealth exist, but the majority of the evidence points towards the feasibility of the intervention in a clinical setting. The mHealth has positive potential for improving maternal and child health outcomes in low-resource settings in India's BIMARU states by strengthening the healthcare system. The results of the study could be used in the tailoring of an effective mHealth intervention and implementation strategy in a similar context. However, there is a need for economic evaluation in the future to bridge the knowledge gap regarding the cost-effectiveness of mHealth interventions.

Improving the efficiency of stroke trials: feasibility and efficacy of group adjudication of functional end points.

BACKGROUND AND PURPOSE: Use of the modified Rankin scale (mRS) in multicenter trials may be limited by interobserver variability. We assessed the effect of this on trial power and developed a novel group adjudication approach. METHODS: We generated power and sample size estimates from simulated trials modeled with varying mRS reliability. We conducted a virtual acute stroke trial across 14 UK sites to develop a group adjudication approach. Traditional mRS interviews, performed at local sites, were digitally recorded and scored by adjudication committee. We assessed the effect of translation by comparing scores in translated mRS interviews, originally conducted in English and Mandarin. Agreement was measured using κ and weighted κ (κw) statistics and intraclass correlation coefficient. RESULTS: Statistical simulations suggest that improving mRS reliability from κ=0.25 to κ=0.5 or 0.7 may allow reductions in sample size of n=386 or 490 in a typical n=2000 study. Our virtual acute stroke trial included 370 participants and 563 mRS video assessments. We adjudicated mRS in 538 of 563 (96%) study visits. At 30 and 90 days, 161 of 280 (57.5%) and 131 of 258 (50.8%) clips showed interobserver disagreement. Agreement within the adjudication committee was good (30-day κw=0.85 [95% confidence interval, 0.81-0.86]; 90-day κw=0.86 [95% confidence interval, 0.82-0.88]) without significant or systematic bias in mRS scoring compared with the local mRS. Interobserver reliability of translated mRS assessments was similar to native language clips (native [n=69] κw=0.91 [95% confidence interval, 0.94-0.99]; translated [n=89] κw=0.90 [95% confidence interval, 0.83-0.96]). CONCLUSIONS: Achievable improvements in interobserver reliability may substantially reduce study sample size, with associated financial benefits. Central adjudication of mRS assessments is feasible (including across international centers), valid and reliable despite the challenges of mRS assessment in large clinical trials.

The Modified Graeb Score: an enhanced tool for intraventricular hemorrhage measurement and prediction of functional outcome.

BACKGROUND AND PURPOSE: Simple and rapid measures of intraventricular hemorrhage (IVH) volume are lacking. We developed and validated a modification of the original Graeb scale to facilitate rapid assessment of IVH over time. METHODS: We explored the relationship between the modified Graeb scale (mGS), original Graeb scale, measured IVH volume, and outcome using data from the Clot Lysis: Evaluating Accelerated Resolution of Hemorrhage with rtPA B (CLEAR B) study. We also explored its reliability. We then evaluated the relationship between mGS and outcome in a large sample of participants with IVH using data contained within the Virtual International Stroke Trials Archive (VISTA). We defined outcome using the modified Rankin scale (>3 signifying poor outcome). RESULTS: The CLEAR B study included 360 scans from 36 subjects. The mGS score and IVH volume were highly correlated (R = 0.80, P<0.0001, R(2) 0.65). Baseline mGS was predictive of poor outcome (area under receiving operating characteristic curve 0.74, 95% confidence interval, 0.57-0.91), whereas the original Graeb scale was not. The VISTA study included 399 participants. Each unit increase in the mGS led to a 12% increase in the odds of a poor outcome (odds ratio, 1.12; 95% confidence interval, 1.05-1.19). Measures of reliability (intra- and inter- reader) were good in both studies. CONCLUSIONS: The mGS, a semiquantitative scale for IVH volume measurement, is a reliable measure with prognostic validity suitable for rapid use in clinical practice and in research.

Preoperative stroke and outcomes after coronary artery bypass graft surgery.

BACKGROUND: Data are lacking on the optimal scheduling of coronary artery bypass grafting (CABG) surgery after stroke. The authors investigated the preoperative predictors of adverse outcomes in patients undergoing CABG, with a focus on the importance of the time interval between prior stroke and CABG. METHODS: The Hospital Episode Statistics database (April 2006-March 2010) was analyzed for elective admissions for CABG. Independent preoperative patient factors influencing length of stay, postoperative stroke, and mortality, were identified by logistic regression and presented as adjusted odds ratios (OR). RESULTS: In all, 62,104 patients underwent CABG (1.8% mortality). Prior stroke influenced mortality (OR 2.20 [95% CI 1.47-3.29]), postoperative stroke (OR 1.99 [1.39-2.85]), and prolonged length of stay (OR 1.31 [1.11-1.56]). The time interval between stroke and CABG did not influence mortality or prolonged length of stay. However, a longer time interval between stroke and CABG surgery was associated with a small increase in risk of postoperative stroke (OR per month elapsed 1.02 [1.00-1.04]; P = 0.047). An interaction was evident between prior stroke and myocardial infarction for death (OR 5.50 [2.84-10.8], indicating the importance of the combination of comorbidities. Prominent effects on mortality were also exerted by liver disease (OR 20.8 [15.18-28.51]) and renal failure (OR 4.59 [3.85-5.46]). CONCLUSIONS: The authors found no evidence that more recent preoperative stroke predisposed patients undergoing CABG surgery to suffer postoperative stroke, death, or prolonged length of stay. The combination of prior stroke and myocardial infarction substantially increased perioperative risk.

Safety, tolerability and pharmacokinetics of MCI-186 in patients with acute ischemic stroke: new formulation and dosing regimen.

BACKGROUND AND PURPOSE: MCI-186 (edaravone) is a free radical scavenger approved in Japan since 2001 for the treatment of patients with acute ischemic stroke within 24 h from the onset of symptoms. It was recommended by the Japanese Guidelines for the Management of Stroke 2004. Our aim was to investigate the safety, tolerability and pharmacokinetics of a new formulation and dose regimen (intravenous bolus plus infusion) of MCI-186 suitable for the treatment of acute ischemic stroke in Europe because the Japanese treatment protocol includes twice-a-day intravenous infusion of MCI-186 for a maximum of 14 days. Such a treatment protocol is not very practical in Europe, where hospital stay is much shorter in acute hospitals. METHODS: In a double-blind, placebo-controlled randomized clinical trial we studied two dosing regimens, each in a cohort of 18 patients. Patients were randomized in a 2:1 ratio in both cohorts to receive MCI-186 or placebo. Review of safety and plasma concentration data from the first cohort (loading dose 0.08 mg/kg + 0.2 mg/kg/h infusion) preceded the second cohort (loading dose 0.16 mg/kg + 0.4 mg/kg/h infusion). Safety parameters included adverse events, severe adverse events, physical examinations, local reactions at infusion site, ECG, clinical chemistry and hematology, modified Total Neuropathy Score and CT scans. RESULTS: Mean age and National Institutes of Health Stroke Scale (NIHSS) score on admission of patients in cohorts 1 and 2 and the placebo group were 64, 63, and 69 years and 5, 5, and 6, respectively. The number of treatment emergent adverse events that occurred was 109, most of which were transient, mild or moderate. Both doses of the new formulation and dosing regimen were well tolerated. After the initiation of the infusion, plasma concentrations of MCI-186 reached or exceeded prespecified target levels within 24 h in both MCI-186 cohorts, which were in the putative therapeutic range in humans. Geometric mean values of MCI-186 plasma concentration at the end of the infusion in cohorts 1 and 2 were 391 and 1,595 ng/ml, respectively. CONCLUSIONS: The primary objective of the present study, safety and tolerability of the new formulation and dosing regimen, was achieved. The new formula and both dosing regimens were well tolerated and achieved intended plasma concentrations suitable for larger safety studies before pivotal trials.

Reframing context specificity in team diagnosis using the theory of distributed cognition.

Context specificity refers to the vexing phenomenon whereby a physician can see two patients with the same presenting complaint, identical history and physical examination findings, but due to specific situational (contextual) factors arrives at two different diagnostic labels. Context specificity remains incompletely understood and undoubtedly leads to unwanted variance in diagnostic outcomes. Previous empirical work has demonstrated that a variety of contextual factors impacts clinical reasoning. These findings, however, have largely focused on the individual clinician; here we broaden this work to reframe context specificity in relation to clinical reasoning by an internal medicine rounding team through the lens of Distributed Cognition (DCog). In this model, we see how meaning is distributed amongst the different members of a rounding team in a dynamic fashion that evolves over time. We describe four different ways in which context specificity plays out differently in team-based clinical care than for a single clinician. While we use examples from internal medicine, we believe that the concepts we present apply equally to other specialties and fields in health care.

Stroke in Hemodialysis Patients Randomized to Different Intravenous Iron Strategies: A Prespecified Analysis from the PIVOTAL Trial.

Background: People with kidney failure treated with hemodialysis (HD) are at increased risk of stroke compared with similarly aged people with normal kidney function. One concern is that treatment of renal anemia might increase stroke risk. We studied risk factors for stroke in a prespecified secondary analysis of a randomized, controlled trial of intravenous iron treatment strategies in HD. Methods: We analyzed data from the Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL) trial, focusing on variables associated with risk of stroke. The trial randomized 2141 adults who had started HD <12 months earlier and who were receiving an erythropoiesis-stimulating agent (ESA) to high-dose IV iron administered proactively or low-dose IV iron administered reactively in a 1:1 ratio. Possible stroke events were independently adjudicated. We performed analyses to identify variables associated with stroke during follow-up and assessed survival following stroke. Results: During a median 2.1 years of follow-up, 69 (3.2%) patients experienced a first postrandomization stroke. Fifty-seven (82.6%) were ischemic strokes, and 12 (17.4%) were hemorrhagic strokes. There were 34 postrandomization strokes in the proactive arm and 35 postrandomization strokes in the reactive arm (hazard ratio, 0.90; 95% confidence interval, 0.56 to 1.44; P=0.66). In multivariable models, women, diabetes, history of prior stroke at baseline, higher baseline systolic BP, lower serum albumin, and higher C-reactive protein were independently associated with stroke events during follow-up. Hemoglobin, total iron, and ESA dose were not associated with risk of stroke. Fifty-eight percent of patients with a stroke event died during follow-up compared with 23% without a stroke. Conclusions: In patients on HD, stroke risk is broadly associated with risk factors previously described to increase cardiovascular risk in this population. Proactive intravenous iron does not increase stroke risk.Clinical Trial registry name and registration number: Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL), 2013-002267-25.

Reliability of the modified Rankin Scale: a systematic review.

BACKGROUND AND PURPOSE: A perceived weakness of the modified Rankin Scale is potential for interobserver variability. We undertook a systematic review of modified Rankin Scale reliability studies. METHODS: Two researchers independently reviewed the literature. Crossdisciplinary electronic databases were interrogated using the following key words: Stroke*; Cerebrovasc*; Modified Rankin*; Rankin Scale*; Oxford Handicap*; Observer variation*. Data were extracted according to prespecified criteria with decisions on inclusion by consensus. RESULTS: From 3461 titles, 10 studies (587 patients) were included. Reliability of modified Rankin Scale varied from weighted kappa=0.95 to kappa=0.25. Overall reliability of mRS was kappa=0.46; weighted kappa=0.90 (traditional modified Rankin Scale) and kappa=0.62; weighted kappa=0.87 (structured interview). CONCLUSION: There remains uncertainty regarding modified Rankin Scale reliability. Interobserver studies closest in design to large-scale clinical trials demonstrate potentially significant interobserver variability.