Relationship between the HLA-B*1502 allele and carbamazepine-induced Stevens-Johnson Syndrome and toxic epidermal necrolysis: a systematic review and meta-analysis

IMPORTANCE: The US Food and Drug Administration recommends screening for the HLA-B*1502 allele before initiation of carbamazepine therapy in patients of Asian ancestry, but there remains unclear evidence of a relationship between HLA-B*1502 and Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) among carbamazepine users, especially in some racial/ethnic populations. OBJECTIVE: To determine the relationship between the HLA-B*1502 allele and carbamazepine-induced SJS and TEN. DATA SOURCES: A comprehensive search of the following data sources was performed without language restriction from the inception of the database until January 8, 2013: EMBASE, PubMed, clinicaltrials.gov, Cochrane Library, IPA (International Pharmaceutical Abstracts), HuGENet (Human Genome Epidemiology Network), and CINAHL (Cumulative Index to Nursing and Allied Health Literature), and the reference lists of identified studies. STUDY SELECTION: Inclusion criteria were studies that investigated the relationship between HLA-B*1502 and carbamazepine-induced SJS and TEN and that reported sufficient data for calculating the frequency of HLA-B*1502 carriers among cases and controls. The search yielded 525 articles, of which 16 met the inclusion criteria. The studies included 227 SJS or TEN cases, 602 matched control subjects, and 2949 population control subjects. DATA EXTRACTION AND SYNTHESIS: Two reviewers independently extracted the following data: study design, eligibility criteria, diagnostic criteria, patient demographics, genotype distribution, HLA-B genotyping technique, selection of cases and controls, dosage of carbamazepine and duration of use, and results of Hardy-Weinberg equilibrium in the control group. The Newcastle-Ottawa Scale was used to assess the quality of studies. The overall odds ratios (ORs) with corresponding 95% CIs were calculated using a random-effects model. The primary analysis was based on matched control studies. Subgroup analyses by race/ethnicity were also performed. MAIN OUTCOME AND MEASURE: The primary outcomewas carbamazepine-induced SJS and TEN. The outcome measure is given as an overall OR. RESULTS: The summary OR for the relationship between HLA-B*1502 and carbamazepine-induced SJS and TEN was 79.84 (95% CI, 28.45-224.06). Racial/ethnic subgroup analyses yielded similar findings for Han-Chinese (115.32; 18.17-732.13), Thais (54.43; 16.28-181.96), and Malaysians (221.00; 3.85-12 694.65). Among individuals of white or Japanese race/ethnicity, no patients with SJS or TEN were carriers of the HLA-B*1502 allele. CONCLUSIONS AND RELEVANCE: We found a strong relationship between the HLA-B*1502 allele and carbamazepine-induced SJS and TEN in Han-Chinese, Thai, and Malaysian populations. HLA-B*1502 screening in patients requiring carbamazepine therapy is warranted

Cost effectiveness of pediatric pneumococcal conjugate vaccines: a comparative assessment of decision-making tools

BACKGROUND: Several decision support tools have been developed to aid policymaking regarding the adoption of pneumococcal conjugate vaccine (PCV) into national pediatric immunization programs. The lack of critical appraisal of these tools makes it difficult for decision makers to understand and choose between them. With the aim to guide policymakers on their optimal use, we compared publicly available decision-making tools in relation to their methods, influential parameters and results. METHODS: The World Health Organization (WHO) requested access to several publicly available cost-effectiveness (CE) tools for PCV from both public and private provenance. All tools were critically assessed according to the WHO's guide for economic evaluations of immunization programs. Key attributes and characteristics were compared and a series of sensitivity analyses was performed to determine the main drivers of the results. The results were compared based on a standardized set of input parameters and assumptions. RESULTS: Three cost-effectiveness modeling tools were provided, including two cohort-based (Pan-American Health Organization (PAHO) ProVac Initiative TriVac, and PneumoADIP) and one population-based model (GlaxoSmithKline's SUPREMES). They all compared the introduction of PCV into national pediatric immunization program with no PCV use. The models were different in terms of model attributes, structure, and data requirement, but captured a similar range of diseases. Herd effects were estimated using different approaches in each model. The main driving parameters were vaccine efficacy against pneumococcal pneumonia, vaccine price, vaccine coverage, serotype coverage and disease burden. With a standardized set of input parameters developed for cohort modeling, TriVac and PneumoADIP produced similar incremental costs and health outcomes, and incremental cost-effectiveness ratios. CONCLUSIONS: Vaccine cost (dose price and number of doses), vaccine efficacy and epidemiology of critical endpoint (for example, incidence of pneumonia, distribution of serotypes causing pneumonia) were influential parameters in the models we compared. Understanding the differences and similarities of such CE tools through regular comparisons could render decision-making processes in different countries more efficient, as well as providing guiding information for further clinical and epidemiological research. A tool comparison exercise using standardized data sets can help model developers to be more transparent about their model structure and assumptions and provide analysts and decision makers with a more in-depth view behind the disease dynamics. Adherence to the WHO guide of economic evaluations of immunization programs may also facilitate this process. Please see related article: http://www.biomedcentral.com/1741-7007/9/55

Association of HLA-B*5801 allele and allopurinol-induced stevens johnson syndrome and toxic epidermal necrolysis: a systematic review and meta-analysis

Background: Despite some studies suggesting a possible association between human leukocyte antigen, HLA-B*5801 and allopurinol induced Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), the evidence of association and its magnitude remain inconclusive. This study aims to systematically review and meta-analyze the association between HLA-B*5801 allele and allopurinol-induced SJS/TEN.Methods: A comprehensive search was performed in databases including MEDLINE, Pre-MEDLINE, Cochrane Library, EMBASE, International Pharmaceutical Abstracts (IPA), CINAHL, PsychInfo, the WHO International, Clinical Trial Registry, and ClinicalTrial.gov from their inceptions to June 2011. Only studies investigating association between HLA-B*5801 with allopurinol-induced SJS/TEN were included. All studies were extracted by two independent authors. The primary analysis was the carrier frequency of HLA-B*5801 comparison between allopurinol-induced SJS/TEN cases and each comparative group. The pooled odds ratios were calculated using a random effect model.Results: A total of 4 studies with 55 SJS/TEN cases and 678 matched-controls (allopurinol-tolerant control) was identified, while 5 studies with 69 SJS/TEN cases and 3378 population-controls (general population) were found. SJS/TEN cases were found to be significantly associated with HLA-B*5801 allele in both groups of studies with matched-control (OR 96.60, 95%CI 24.49-381.00, p < 0.001) and population-control (OR 79.28, 95%CI 41.51-151.35, p < 0.001). Subgroup analysis for Asian and Non-Asian population yielded similar findings.Conclusion: We found a strong and significant association between HLA-B*5801 and allopurinol-induced SJS/TEN. Therefore, HLA-B*5801 allele screening may be considered in patients who will be treated with allopurinol