Investigating Confidence Intervals of Item Parameters When Some Item Parameters Take Priors in the 2PL and 3PL Models.

To reduce the chance of Heywood cases or nonconvergence in estimating the 2PL or the 3PL model in the marginal maximum likelihood with the expectation-maximization (MML-EM) estimation method, priors for the item slope parameter in the 2PL model or for the pseudo-guessing parameter in the 3PL model can be used and the marginal maximum a posteriori (MMAP) and posterior standard error (PSE) are estimated. Confidence intervals (CIs) for these parameters and other parameters which did not take any priors were investigated with popular prior distributions, different error covariance estimation methods, test lengths, and sample sizes. A seemingly paradoxical result was that, when priors were taken, the conditions of the error covariance estimation methods known to be better in the literature (Louis or Oakes method in this study) did not yield the best results for the CI performance, while the conditions of the cross-product method for the error covariance estimation which has the tendency of upward bias in estimating the standard errors exhibited better CI performance. Other important findings for the CI performance are also discussed.

A note on computing Louis' observed information matrix identity for IRT and cognitive diagnostic models.

Using Louis' formula, it is possible to obtain the observed information matrix and the corresponding large-sample standard error estimates after the expectation-maximization (EM) algorithm has converged. However, Louis' formula is commonly de-emphasized due to its relatively complex integration representation, particularly when studying latent variable models. This paper provides a holistic overview that demonstrates how Louis' formula can be applied efficiently to item response theory (IRT) models and other popular latent variable models, such as cognitive diagnostic models (CDMs). After presenting the algebraic components required for Louis' formula, two real data analyses, with accompanying numerical illustrations, are presented. Next, a Monte Carlo simulation is presented to compare the computational efficiency of Louis' formula with previously existing methods. Results from these presentations suggest that Louis' formula should be adopted as a standard method when computing the observed information matrix for IRT models and CDMs fitted with the EM algorithm due to its computational efficiency and flexibility.

Global implementation of the world health organization's International Classification of Diseases (ICD)-11: The allergic and hypersensitivity conditions model.

The International Classification of Diseases (ICD) provides a common language for use worldwide as a diagnostic and classification tool for epidemiology, clinical purposes and health management. Since its first edition, the ICD has maintained a framework distributing conditions according to topography, with the result that some complex conditions, such as allergies and hypersensitivity disorders (A/H) including anaphylaxis, have been poorly represented. The change in hierarchy in ICD-11 permitted the construction of the pioneer section addressed to A/H, which may result in more accurate mortality and morbidity statistics, including more accurate accounting for mortality due to anaphylaxis, strengthen classification, terminology and definitions. The ICD-11 was presented and adopted by the 72nd World Health Assembly in May 2019, and the implementation is ongoing worldwide. We here present the outcomes from an online survey undertaken to reach out the allergy community worldwide in order to peer review the terminology, classification and definitions of A/H introduced into ICD-11 and to support their global implementation. Data are presented here for 406 respondents from 74 countries. All of the subsections of the new A/H section of the ICD-11 had been considered with good accuracy by the majority of respondents. We believe that, in addition to help during the implementation phase, all the comments provided will help to improve the A/H classification and to increase awareness by different disciplines of what actions are needed to ensure more accurate epidemiological data and better clinical management of A/H patients.

Changing the history of anaphylaxis mortality statistics through the World Health Organization's International Classification of Diseases-11.

We review the history of the classification and coding changes for anaphylaxis and provide current and perspective information in the field. In 2012, an analysis of Brazilian data demonstrated undernotification of anaphylaxis-related deaths because of the difficulties of coding using the International Classification of Diseases, 10th Revision. This work triggered strategic international actions supported by the Joint Allergy Academies and the International Classification of Diseases World Health Organization (WHO) leadership to update the classification of allergic disorders for the International Classification of Diseases, 11th Revision (ICD-11), which resulted in construction of the pioneer "Allergic and hypersensitivity conditions" chapter. The usability of the new framework has been tested by evaluating the same data published in 2012 from the ICD-11 perspective. Coding accuracy was much improved, reaching 95% for definite anaphylaxis. As the results were provided to the WHO Mortality Reference Group, coding rules have been changed, allowing anaphylaxis to be recorded as an underlying cause of death in official mortality statistics. The mandatory use of ICD-11 from January 2022 for documenting cause of death could have 2 immediate consequences: (1) the reported number of anaphylaxis-related deaths might increase because of more appropriate coding and (2) the cross-sectional and longitudinal mortality data generated might ultimately lead to a better understanding of anaphylaxis epidemiology and improved health policies directed at reducing anaphylaxis-related mortality.

WITHDRAWN: Interventions for guttate psoriasis.

BACKGROUND: Guttate psoriasis is a distinctive acute form of psoriasis which characteristically occurs in children and young adults. Very little specific evidence-based guidance is available in standard texts to help make rational decisions about treatment options. OBJECTIVES: To assess the effectiveness of treatments for guttate psoriasis. SEARCH METHODS: We searched the Cochrane Clinical Trials Register (Cochrane Library, Issue 3, 1999), Medline (1966- September 1999), Embase (1988-September 1999), Salford Database of Psoriasis Trials (to November 1999) and European Dermato-Epidemiology Network (EDEN) Psoriasis Trials Database (to November 1999) for terms GUTTATE and PSORIASIS. We also searched 100 unselected RCTs of psoriasis therapy and all 112 RCTs of phototherapy for psoriasis in the Salford Database of Psoriasis Trials for separate stratification for guttate psoriasis. SELECTION CRITERIA: Randomised trials in which patients with acute guttate psoriasis were randomised to different treatments, except those trials examining antistreptococcal interventions which are addressed in a separate Cochrane review. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial eligibility and quality. MAIN RESULTS: No published report could be found to support or to challenge current commonly used methods of management.Only one trial which met the selection criteria was identified. In this small study of 21 hospitalised patients with guttate psoriasis, intravenous infusion of an n-3 fatty acid rich lipid emulsion was compared with placebo emulsion containing n-6 fatty acids. The n-3 preparation appeared to be of some benefit for patients with guttate psoriasis. AUTHORS' CONCLUSIONS: There is currently no firm evidence on which to base treatment of acute guttate psoriasis. Studies comparing standard treatment modalities, including phototherapy and topical regimens, are required to enable informed decisions on treatment choices to be made.

Developing an international standard for the classification of surface anatomic location for use in clinical practice and epidemiologic research.

BACKGROUND: There is currently no universally adopted terminology for defining human surface anatomic location. The lack of precision, accuracy, and reliability of terms used by health care providers, in particular dermatologic surgeons, is unsatisfactory both for epidemiologic research and for high-quality patient care. OBJECTIVE: We sought to create a clinically relevant yet concise surface anatomy terminology for international use including the International Classification of Diseases and to map it to existing disparate terminologies. METHODS: Widely used surface anatomy terminology data sets and diagrams were reviewed. A Delphi consensus convened to create a novel surface anatomy terminology. The new terminology was hierarchically mapped to Systematized Nomenclature of Medicine terms and New York University numbers and physically mapped to 2-dimensional anatomic diagrams for clarity and reproducibility. RESULTS: The final terminology data set contains 519 discrete terms arranged in a 9-level hierarchy and has been adopted by the World Health Organization for the International Classification of Diseases, 11th revision. LIMITATIONS: Specification of most locations requires linking to laterality qualifiers. Fine granularity for larger sites may require the use of additional qualifiers. CONCLUSION: Consistent use of precise and accurate surface anatomy terms is crucial to the practice of dermatology, particularly procedural dermatology. The proposed terminology is designed to form the basis for evolution of a universally adoptable terminology set to improve patient care, interprovider communication, and epidemiologic tracking.

WITHDRAWN: Antistreptococcal interventions for guttate and chronic plaque psoriasis.

BACKGROUND: Guttate psoriasis is a distinctive acute form of psoriasis which characteristically occurs in children and young adults. It is closely associated with preceding streptococcal sore throat or tonsillitis. Some authorities have claimed that ordinary (chronic plaque) psoriasis may also be made worse by infection at distant sites. Although many dermatologists have recommended using antibiotics for guttate psoriasis in particular, it is not clear whether they influence the course of either form of psoriasis. Some dermatologists have also recommended tonsillectomy for psoriasis in patients with recurrent streptococcal sore throat. OBJECTIVES: To assess the evidence for effectiveness of antistreptococcal interventions including antibiotics and tonsillectomy in the management of acute guttate and chronic plaque psoriasis. SEARCH METHODS: We searched the Cochrane Clinical Trials Register (Cochrane Library, Issue 3, 1999), Medline (1966- September 1999), Embase (1988-September 1999), the Salford Database of Psoriasis Trials (to November 1999) and the European Dermato-Epidemiology Network (EDEN) Psoriasis Trials Database (to November 1999) for terms [STREPTOCOCC* or ANTIBIOTIC* or TONSIL*] and PSORIASIS using the Cochrane Skin Group search strategy. SELECTION CRITERIA: Randomised trials of one or more antistreptococcal interventions in patients with guttate or chronic plaque psoriasis. DATA COLLECTION AND ANALYSIS: Two reviewers independently examined each retrieved trial for eligibility and quality. MAIN RESULTS: The one eligible trial we identified compared the use of two oral antibiotic schedules in 20 psoriasis patients, predominantly of guttate type, who had evidence of beta-haemolytic streptococcal colonisation. Either rifampicin or placebo was added to the end of a standard course of antistreptococcal antibiotic (phenoxymethylpenicillin or erythromycin). No patient in either arm of the study improved during the observation period.No randomised trials of tonsillectomy for psoriasis were identified. AUTHORS' CONCLUSIONS: Although it is well known that guttate psoriasis may be precipitated by streptococcal infection, there is no firm evidence to support the use of antibiotics either in the management of established guttate psoriasis or in preventing the development of guttate psoriasis following streptococcal sore throat.Although both antibiotics and tonsillectomy have frequently been advocated for patients with recurrent guttate psoriasis or chronic plaque psoriasis, there is to date no good evidence that either intervention is beneficial.

Reaching multidisciplinary consensus on classification of anaphylaxis for the eleventh revision of the World Health Organization's (WHO) International Classification of Diseases (ICD-11).

BACKGROUND: Although currently misclassified in the International Classification of Diseases (ICD) and still not officially listed as a rare disease, anaphylaxis is a well-known clinical emergency. Anaphylaxis is now one of the principal headings in the "Allergic and hypersensitivity conditions" section recently compiled for the forthcoming 11th Revision of ICD (ICD-11). We here report the building process used for the pioneering "Anaphylaxis" subsection of ICD-11 in which we aimed for transparency as recommended in the ICD-11 revision guidelines. RESULTS: During an online intensive scientific and technical discussions with ICD-11 Topic Advisory Groups and Expert Working Groups, we drafted a total of 35 proposals for the classification of anaphylaxis. From all the 35 proposals, 77% were implemented, 20% remain to be implemented, and the others being partially implemented (1.5%) or rejected (1.5%). CONCLUSION: For the first time, anaphylaxis is now properly classified and has attained greater visibility within ICD. In addition to all the benefits expected from the actions we have undertaken in updating the terminology, definitions and classification of allergic and hypersensitivity conditions for ICD-11, we strongly believe that anaphylaxis should be a public health priority and that it should therefore be formally added into the list of rare diseases in order to support awareness and quality clinical management of patients.

Collaboration between specialties for respiratory allergies in the International Classification of Diseases (ICD)-11.

BACKGROUND: The International Classification of Diseases (ICD) has been grouping the allergic and hypersensitivity disorders involving the respiratory tract under topographic distribution, regardless of the underlying mechanisms, triggers or concepts currently in use for allergic and hypersensitivity conditions. In order to strengthen awareness and deliberate the creation of the new "Allergic or hypersensitivity disorders involving the respiratory tract" section of the ICD-11, we here propose make the building process public. METHODS: The new frame has been constructed to cover the gaps previously identified and was based on consensus academic reports and ICD-11 principles. Constant and bilateral discussion was kept with relevant groups representing specialties and resulted in proposals submission into the ICD-11 online platform. RESULTS: The "Allergic or hypersensitivity disorders involving the respiratory tract" section covers 64 entities distributed across five main categories. All the 79 proposals submitted resulted from an intensive collaboration of the Allergy working group, relevant Expert working groups and the WHO ICD governance. CONCLUSION: The establishment of the ICD-11 "Allergic or hypersensitivity disorders involving the respiratory tract" section will allow the dissemination of the updated concepts to be used in clinical practice by many different specialties and health professionals.

Use of ontology structure and Bayesian models to aid the crowdsourcing of ICD-11 sanctioning rules.

The International Classification of Diseases (ICD) is the de facto standard international classification for mortality reporting and for many epidemiological, clinical, and financial use cases. The next version of ICD, ICD-11, will be submitted for approval by the World Health Assembly in 2018. Unlike previous versions of ICD, where coders mostly select single codes from pre-enumerated disease and disorder codes, ICD-11 coding will allow extensive use of multiple codes to give more detailed disease descriptions. For example, "severe malignant neoplasms of left breast" may be coded using the combination of a "stem code" (e.g., code for malignant neoplasms of breast) with a variety of "extension codes" (e.g., codes for laterality and severity). The use of multiple codes (a process called post-coordination), while avoiding the pitfall of having to pre-enumerate vast number of possible disease and qualifier combinations, risks the creation of meaningless expressions that combine stem codes with inappropriate qualifiers. To prevent that from happening, "sanctioning rules" that define legal combinations are necessary. In this work, we developed a crowdsourcing method for obtaining sanctioning rules for the post-coordination of concepts in ICD-11. Our method utilized the hierarchical structures in the domain to improve the accuracy of the sanctioning rules and to lower the crowdsourcing cost. We used Bayesian networks to model crowd workers' skills, the accuracy of their responses, and our confidence in the acquired sanctioning rules. We applied reinforcement learning to develop an agent that constantly adjusted the confidence cutoffs during the crowdsourcing process to maximize the overall quality of sanctioning rules under a fixed budget. Finally, we performed formative evaluations using a skin-disease branch of the draft ICD-11 and demonstrated that the crowd-sourced sanctioning rules replicated those defined by an expert dermatologist with high precision and recall. This work demonstrated that a crowdsourcing approach could offer a reasonably efficient method for generating a first draft of sanctioning rules that subject matter experts could verify and edit, thus relieving them of the tedium and cost of formulating the initial set of rules.

Assessing psoriasis severity and outcomes for clinical trials and routine clinical practice.

Psoriasis is a complex disease. Dermatologists have not documented psoriasis severity, except in clinical trials; doing so requires tools for assessing psoriasis and an understanding of what changes in those assessments mean in terms of outcome. Two psoriasis assessment tools have dominated: The Psoriasis Area and Severity Index and the Dermatology Life Quality Index. There are advantages and disadvantages to each. Newer instruments may not be more suitable for documenting psoriasis. There may be benefits in terms of patient ownership of disease management from using self-assessment tools for documenting severity, for example, the Self-assessment version of the Simplified Psoriasis Index.

Responsiveness to change and interpretability of the simplified psoriasis index.

The Simplified Psoriasis Index (SPI) is a summary measure of psoriasis with separate components for current severity (weighted for functionally or psychosocially important sites), psychosocial impact, and past behavior. The current severity components of the professionally assessed SPI (proSPI-s) and self-assessed SPI (saSPI-s) have each been shown to be valid and reliable. Their responsiveness to change and equivalence to the current standard (Psoriasis Area and Severity Index, PASI) were investigated. Responsiveness and minimum clinically important differences (MCIDs) were derived from PASI changes from baseline at weeks 4 (n=100) and 10 (n=65) in patients commencing therapy for psoriasis. Receiver operating characteristic (ROC) analysis confirmed that both measures detected responsiveness well (area under the curve (AUC)=0.72-0.96). On ROC and PASI-based anchor analysis, MCIDs equated to mean absolute and percentage changes of 5 and 60% (proSPI-s), and 7 and 70% (saSPI-s). Satisfactory response as defined by 75% reduction in PASI equated to 85 and 95% reductions in proSPI-s and saSPI-s, respectively. PASI-equivalent cutoff scores for mild (PASI<10) and severe (PASI>20) psoriasis were <9 and >18 for proSPI-s (n=300) and <10 and >20 for saSPI-s (n=200; AUC=0.86-0.96). These studies further support the validity of SPI for use in routine clinical practice.

The Simplified Psoriasis Index (SPI): a practical tool for assessing psoriasis.

The Simplified Psoriasis Index (SPI) is a summary measure of psoriasis with separate components for current severity (SPI-s), psychosocial impact (SPI-p), and past history and interventions (SPI-i). It derives from the Salford Psoriasis Index but replaces Psoriasis Area and Severity Index (PASI) with a composite weighted severity score designed to reflect the impact of psoriasis affecting functionally or psychosocially important body sites. Two complementary versions are available, differing only in that current severity (SPI-s) is either professionally (proSPI-s) or patient self-assessed (saSPI-s). This study examined the criterion and construct validity and response distribution of proSPI-s, saSPI-s, and SPI-p in 100 patients with plaque psoriasis. A further 50 patients were assessed for test-retest reliability of these three components. Interrater reliability of proSPI-s was assessed in 12 patients, each assessed by 12 assessors (144 assessments). There was close correlation between PASI and proSPI-s (r=0.91); SPI-p was closely correlated with the Dermatology Life Quality Index (r=0.89). Strong intrarater (proSPI-s, saSPI-s, SPI-p, and SPI-i) and interrater (proSPI-s) reliability was demonstrated (all intraclass correlation coefficients >0.75). There were wide response distributions for all three components. We believe that both professional (proSPI) and self-assessed (saSPI) versions can readily be introduced into routine clinical practice.

Nonhealing vegetating plaque on the finger: tuberculosis verrucosa cutis.

Tuberculosis verrucosa cutis is an uncommon form of tuberculosis that typically presents as a chronic warty plaque. It develops in individuals with moderate to high immunity to Mycobacterium tuberculosis due to inoculation of an open wound. We present the case of a Somali man born in the United Kingdom who presented with a nonhealing ulcer on the right hand of 10 years' duration. The patient was diagnosed with tuberculosis verrucosa cutis based on clinical suspicion, which was confirmed by several investigations including strongly positive results of a Mantoux test, IFN-gamma release assay, typical histology on skin biopsy, and polymerase chain reaction (PCR) analysis positive for mycobacterial DNA. Treatment with quadruple antituberculous therapy produced rapid resolution of the ulcer. This unusual condition often is overlooked in the differential diagnosis of nonhealing ulcers, yet it has an excellent prognosis with treatment. A high index of suspicion is required.