A comprehensive framework to estimate the frequency, duration and risk factors for diagnostic delays using simulation-based methods

The incidence of diagnostic delays is unknown for many diseases and particular healthcare settings. Many existing methods to identify diagnostic delays are resource intensive or inapplicable to various diseases or settings. In this paper we propose a comprehensive framework to estimate the frequency of missed diagnostic opportunities for a given disease using real-world longitudinal data sources. We start by providing a conceptual model of the disease-diagnostic, data-generating process. We then propose a simulation-based method to estimate measures of the frequency of missed diagnostic opportunities and duration of delays. This approach is specifically designed to identify missed diagnostic opportunities based on signs and symptoms that occur prior to an initial diagnosis, while accounting for expected patterns of healthcare that may appear as coincidental symptoms. Three different simulation algorithms are described for implementing this approach. We summarize estimation procedures that may be used to parameterize the simulation. Finally, we apply our approach to the diseases of tuberculosis, acute myocardial infarction, and stroke and evaluate the estimated frequency and duration of diagnostic delays for these diseases. Our approach can be customized to fit a range of disease and we summarize how the choice of simulation algorithm may impact the resulting estimates.

Incidence, duration and risk factors associated with missed opportunities to diagnose herpes simplex encephalitis: A population-based longitudinal study

Background Delays in diagnosing herpes simplex encephalitis (HSE) are associated with increased morbidity and mortality. The purpose of this paper is to determine the frequency and duration of diagnostic delays for HSE and risk factors for diagnostic delays. Methods Using data from the IBM Marketscan Databases, 2001-2017, we performed a retrospective cohort study of patients with HSE. We estimated the number of visits with HSE-related symptoms prior to diagnosis that would be expected to occur in the absence of delays and compared this estimate to the observed pattern of visits. Next, we used a simulation-based approach to compute the number of visits representing a delay, the number of missed diagnostic opportunities per case patient and the duration of delays. We also investigated potential risk factors for delays. Results We identified 2667 patients diagnosed with HSE. We estimated 45.9% (95% CI 43.6%-48.1%) of patients experienced at least one missed opportunity; 21.9% (95% CI 17.3%-26.3%) of these patients had delays lasting >7 days. Risk factors for delays included being seen only in the emergency department, age < 65, a history of sinusitis or schizophrenia. Conclusions Many patients with HSE experience multiple missed diagnostic opportunities prior to diagnosis.

Incidence, origins and avoidable harm of missed opportunities in diagnosis: longitudinal patient record review in 21 English general practices

BackgroundDiagnostic error is a global patient safety priority.ObjectivesTo estimate the incidence, origins and avoidable harm of diagnostic errors in English general practice. Diagnostic errors were defined as missed opportunities to make a correct or timely diagnosis based on the evidence available (missed diagnostic opportunities, MDOs).MethodRetrospective medical record reviews identified MDOs in 21 general practices. In each practice, two trained general practitioner reviewers independently conducted case note reviews on 100 randomly selected adult consultations performed during 2013–2014. Consultations where either reviewer identified an MDO were jointly reviewed.ResultsAcross 2057 unique consultations, reviewers agreed that an MDO was possible, likely or certain in 89 cases or 4.3% (95% CI 3.6% to 5.2%) of reviewed consultations. Inter-reviewer agreement was higher than most comparable studies (Fleiss’ kappa=0.63). Sixty-four MDOs (72%) had two or more contributing process breakdowns. Breakdowns involved problems in the patient–practitioner encounter such as history taking, examination or ordering tests (main or secondary factor in 61 (68%) cases), performance and interpretation of diagnostic tests (31; 35%) and follow-up and tracking of diagnostic information (43; 48%). 37% of MDOs were rated as resulting in moderate to severe avoidable patient harm.ConclusionsAlthough MDOs occurred in fewer than 5% of the investigated consultations, the high numbers of primary care contacts nationally suggest that several million patients are potentially at risk of avoidable harm from MDOs each year. Causes of MDOs were frequently multifactorial, suggesting the need for development and evaluation of multipronged interventions, along with policy changes to support them.

Incidence, duration and risk factors associated with delayed and missed diagnostic opportunities related to tuberculosis: a population-based longitudinal study

ObjectivesMissed opportunities to diagnose tuberculosis are costly to patients and society. In this study, we (1) estimate the frequency and duration of diagnostic delays among patients with active pulmonary tuberculosis and (2) determine the risk factors for experiencing a diagnostic delay.DesignA retrospective cohort study of patients with tuberculosis using longitudinal healthcare encounters prior to diagnosis.SettingCommercially insured enrollees from the Commercial Claims and Encounters or Medicare Supplemental IBM Marketscan Research Databases, 2001–2017.ParticipantsAll patients diagnosed with, and receiving treatment for, pulmonary tuberculosis, enrolled at least 365 days prior to diagnosis.Primary and secondary outcome measuresWe estimated the number of visits with tuberculosis-related symptoms prior to diagnosis that would be expected to occur in the absence of delays and compared this estimate to the observed pattern. We computed the number of visits representing a delay and used a simulation-based approach to estimate the number of patients experiencing a delay, number of missed opportunities per patient and duration of delays (ie, time between diagnosis and earliest missed opportunity). We also explored risk factors for missed opportunities.ResultsWe identified 3371 patients diagnosed and treated for active tuberculosis that could be followed up for 1 year prior to diagnosis. We estimated 77.2% (95% CI 75.6% to 78.7%) of patients experienced at least one missed opportunity; of these patients, an average of 3.89 (95% CI 3.65 to 4.14) visits represented a missed opportunity, and the mean duration of delay was 31.66 days (95% CI 28.51 to 35.11). Risk factors for delays included outpatient or emergency department settings, weekend visits, patient age, influenza season presentation, history of chronic respiratory symptoms and prior fluoroquinolone use.ConclusionsMany patients with tuberculosis experience multiple missed diagnostic opportunities prior to diagnosis. Missed opportunities occur most commonly in outpatient settings and numerous patient-specific, environment-specific and setting-specific factors increase risk for delays.

Diagnostic Evaluation Low Yield for Patients with a Lower-Risk Brief Resolved Unexplained Event

In contrast to patients with an apparent life-threatening event (ALTE), the American Academy of Pediatrics recommends very limited evaluation for patients categorized as lower-risk brief resolved unexplained event (BRUE). This retrospective review aims to explore potential missed diagnostic opportunities for patients with a lower-risk BRUE (n = 10) through comparison with a subset of patients with ALTE (n = 72). None of the patients with a lower-risk BRUE had laboratory, imaging or ancillary studies that were diagnostic. Among patients with ALTE, 5 had laboratory and 3 had imaging studies that were diagnostic. None of the patients with a lower-risk BRUE had recurrent events during hospitalization or a serious underlying diagnosis identified within the 90 day follow-up period. As recommended by the AAP, patients with a lower-risk BRUE do not need diagnostic evaluation and can be discharged home with outpatient follow-up.

Using Online Patient Simulations to Identify the Clinical Reasoning Strategies of Medical Students: A Mixed Methods Study (Preprint)

BACKGROUND Improving clinical reasoning skills — the thought processes used by clinicians during consultations to formulate appropriate questions and diagnoses — is essential for reducing missed diagnostic opportunities. The electronic Clinical Reasoning Educational Simulation Tool (eCREST) was developed to improve future doctors’ clinical reasoning skills. A feasibility study demonstrated acceptability and potential impacts but the processes by which students developed their clinical reasoning is unknown. OBJECTIVE To identify and characterize final-year medical students’ clinical reasoning strategies while using eCREST; to explore how students interacted with eCREST. METHODS A sequential mixed methods design was used. Quantitative data captured in a feasibility trial across three UK medical schools (n=148) was used to identify typologies of reasoning, based on the proportion of essential information students identified and the proportion of relevant questions they asked a virtual patient. Strategies were compared between the intervention and control group. A qualitative think-aloud and semi-structured interview study was then undertaken with 16 final year medical students from one medical school to explore how students reasoned while using eCREST. Themes generated from qualitative data were used to expand the typologies of strategies. RESULTS Three types of clinical reasoning strategy were identified: ‘Focused’ (elicited most essential information and asked few irrelevant questions; n=78/148, 53%), ‘Thorough’ (elicited most essential information but asked many irrelevant questions; n=33/148, 22%) and ‘Succinct’ (elicited little essential information but asked few irrelevant questions; n=27/148, 18%). One group were ‘Non-strategic’ (did not elicit enough essential information and asked mostly irrelevant questions; n=10/148, 7%). In the feasibility trial, the intervention group, were significantly more likely to adopt a ‘Thorough’ strategy than controls (21/78, 27% vs 6/70, 9%) and less likely to adopt a ‘Succinct’ strategy (13/78, 17% vs 20/70, 29%); χ2 (3)=9.87, P=.02. Use of other strategies were similar across groups. Thematic analysis identified three dimensions underpinning reasoning: data gathering processes, generating diagnostic hypotheses, confidence and uncertainty. The mixed methods analysis indicated that those classified as ‘Thorough’ asked many questions to avoid missing key information and reported that eCREST helped them to manage uncertainty. The ‘Succinct’ group aimed to limit the number of questions asked and eCREST helped them to focus on asking pertinent questions. The ‘Focused’ group had clear rationales for asking questions but those who used a ‘Non-strategic’ approach did not and may have found eCREST less useful in developing their clinical reasoning. CONCLUSIONS Students apply a range of clinical reasoning strategies to online patient simulations like eCREST. eCREST led students to use more ‘Thorough’ strategies and students reported it helped them to manage uncertainty, which could help future doctors to identify missed diagnostic opportunities. eCREST could also be used by educators to support students to develop their clinical reasoning strategies.

Stop, think SCORTCH: rethinking the traditional ‘TORCH’ screen in an era of re-emerging syphilis

BackgroundThe epidemiology of congenital infections is ever changing, with a recent resurgence in syphilis infection rates seen in the UK. Identification of congenital infection is often delayed; early recognition and management of congenital infections is important. Testing modalities and investigations are often limited, leading to missed diagnostic opportunities.MethodsThe SCORTCH (syphilis, cytomegalovirus (CMV), ‘other’, rubella, toxoplasmosis, chickenpox, herpes simplex virus (HSV) and blood-borne viruses) acronym increases the awareness of clinicians to the increased risk of congenital syphilis, while considering other infectious aetiologies including: zika, malaria, chagas disease, parvovirus, enterovirus, HIV, hepatitis B and C, and human T-lymphotropic virus 1, in addition to the classic congenital infections recognised in the ‘TORCH screen’ (toxoplasmosis, ‘other’, rubella, CMV, HSV). The SCORTCH diagnostic approach describes common signs present in infants with congenital infection, details serological testing for mother and infant and important direct diagnostics of the infant. Direct diagnostic investigations include: radiology, ophthalmology, audiology, microbiological and PCR testing for both the infant and placental tissue, the latter also warrants histopathology.ConclusionThe traditional ‘TORCH screen’ focuses on serology-specific investigations, often omits important direct diagnostic testing of the infant, and fails to consider emerging and re-emerging congenital infections. In recognition of syphilis as a re-emerging pathogen and the overlapping clinical presentations of various infectious aetiologies, we advocate for a broader outlook using the SCORTCH diagnostic approach.

Cerebrospinal Fluid Findings Are Poor Predictors of Appropriate FilmArray Meningitis/Encephalitis Panel Utilization in Pediatric Patients

ABSTRACT Molecular testing of cerebrospinal fluid (CSF) using the BioFire FilmArray meningitis/encephalitis (FA-M/E) panel permits rapid, simultaneous pathogen detection. Due to the broad spectrum of targeted organisms, FA-M/E testing may be restricted to patients with abnormal CSF findings. We sought to determine if restriction is appropriate in our previously healthy and/or immunocompromised pediatric patients. FA-M/E was ordered on 1,025 CSF samples from 948 patients; 121 (11.8%) specimens were FA-M/E positive. Of these, 89 (73.6%) were virus positive, and 30 (24.8%) were bacterium positive. The most common targets detected were enterovirus (n = 38), human herpesvirus 6 (HHV-6) (n = 30), and Streptococcus pneumoniae (n = 14). Pleocytosis with white blood cell (WBC) levels of ≥5 cells/mm3 and ≥10 cells/mm3 were found in 33.1% and 24.3% of all specimens, respectively. Using WBC levels of ≥5 cells/mm3, 63.4% (59/93) of positive specimens exhibited pleocytosis, compared to 29.5% (233/789) of negative specimens. Among positive specimens, 54.4% (37/68) of viral and 87% (20/23) of bacterial cases had pleocytosis. The use of a pleocytosis cutoff of ≥10 cells/mm3 would have missed an additional enterovirus, one cytomegalovirus (CMV), and two HHV-6 diagnoses. CSF glucose and protein levels were normal for 83/116 (75.2%) and 51/116 (44%) positive specimens. Abnormal glucose in combination with WBC levels of ≥10 cells/mm3 showed high specificity (94.5%) and was a better predictor of FA-M/E positivity than abnormal protein. Sensitivity and positive predictive values were <90% for all biomarkers. CSF pleocytosis and abnormal glucose/protein were poor predictors of FA-M/E. Restricting FA-M/E orders based on pleocytosis or other abnormal parameters would have resulted in missed diagnostic opportunities, particularly for the detection of viruses in both previously healthy and immunocompromised patients.