Mining the Medical and Patent Literature to Support Healthcare and Pharmacovigilance

Recent advancements in healthcare practices and the increasing use of information technology in the medical domain has lead to the rapid generation of free-text data in forms of scientific articles, e-health records, patents, and document inventories. This has urged the development of sophisticated information retrieval and information extraction technologies. A fundamental requirement for the automatic processing of biomedical text is the identification of information carrying units such as the concepts or named entities. In this context, this work focuses on the identification of medical disorders (such as diseases and adverse effects) which denote an important category of concepts in the medical text. Two methodologies were investigated in this regard and they are dictionary-based and machine learning-based approaches. Futhermore, the capabilities of the concept recognition techniques were systematically exploited to build a semantic search platform for the retrieval of e-health records and patents. The system facilitates conventional text search as well as semantic and ontological searches. Performance of the adapted retrieval platform for e-health records and patents was evaluated within open assessment challenges (i.e. TRECMED and TRECCHEM respectively) wherein the system was best rated in comparison to several other competing information retrieval platforms. Finally, from the medico-pharma perspective, a strategy for the identification of adverse drug events from medical case reports was developed. Qualitative evaluation as well as an expert validation of the developed system's performance showed robust results. In conclusion, this thesis presents approaches for efficient information retrieval and information extraction from various biomedical literature sources in the support of healthcare and pharmacovigilance. The applied strategies have potential to enhance the literature-searches performed by biomedical, healthcare, and patent professionals. The applied strategies have potential to enhance the literature-searches performed by biomedical, healthcare, and patent professionals. This can promote the literature-based knowledge discovery, improve the safety and effectiveness of medical practices, and drive the research and development in medical and healthcare arena

Identificação e análise de estados de saúde em mensagens do twitter

Social media has become very widely used all over the world for its ability to connect people from different countries and create global communities. One of the most prominent social media platforms is Twitter. Twitter is a platform where users can share text segments with a maximum length of 280 characters. Due to the nature of the platform, it generates very large amounts of text data about its users’ lives. This data can be used to extract health information about a segment of the population for the purpose of public health surveillance. Social Media Mining for Health Shared Task is a challenge that encompasses many Natural Language Processing tasks related to the use of social media data for health research purposes. This dissertation describes the approach I used in my participation in the Social Media Mining for Health Shared Task. I participated in task 1 of the Shared Task. This task was divided into three subtasks. Subtask 1a consisted of the classification of Tweets regarding the presence of Adverse Drug Events. Subtask 1b was a Named Entity Recognition task that aimed at detecting Adverse Drug Effect spans in tweets. Subtask 1c was a normalization task that sought to match an Adverse Drug Event mention to a Medical Dictionary for Regulatory Activities preferred term ID. Toward discovering the best approach for each of the subtasks I made many experiments with different models and techniques to distinguish the ones that were more suited for each subtask. To solve these subtasks, I used transformer-based models as well as other techniques that aim at solving the challenges present in each of the subtasks. The best-performing approach for subtask 1a was a BERTweet large model trained with an augmented training set. As for subtask 1b, the best results were obtained through a RoBERTa large model with oversampled training data. Regarding subtask 1c, I used a RoBERTa base model trained with data from an additional dataset beyond the one made available by the shared task organizers. The systems used for subtasks 1a and 1b both achieved state-of-the-art performance, however, the approach for the third subtask was not able to achieve favorable results. The system used in subtask 1a achieved an F1 score of 0.698, the one used in subtask 1b achieved a relaxed F1 score of 0.661, and the one used in the final subtask achieved a relaxed F1 score of 0.116.As redes sociais tornaram-se muito utilizadas por todo o mundo, permitindo ligar pessoas de diferentes países e criar comunidades globais. O Twitter, uma das redes sociais mais populares, permite que os seus utilizadores partilhem segmentos curtos de texto com um máximo de 280 caracteres. Esta partilha na rede gera uma enorme quantidade de dados sobre os seus utilizadores, podendo ser analisados sobre múltiplas perspetivas. Por exemplo, podem ser utilizados para extrair informação sobre a saúde de um segmento da população tendo em vista a vigilância de saúde pública. O objetivo deste trabalho foi a investigação e o desenvolvimento de soluções técnicas para participar no “Social Media Mining for Health Shared Task” (#SMM4H), um desafio constituído por diversas tarefas de processamento de linguagem natural relacionadas com o uso de dados provenientes de redes sociais para o propósito de investigação na área da saúde. O trabalho envolveu o desenvolvimento de modelos baseados em transformadores e outras técnicas relacionadas, para participação na tarefa 1 deste desafio, que por sua vez está dividida em 3 subtarefas: 1a) classificação de tweets relativamente à presença ou não de eventos adversos de medicamentos (ADE); 1b) reconhecimento de entidades com o objetivo de detetar menções de ADE; 1c) tarefa de normalização com o objetivo de associar as menções de ADE ao termo MedDRA correspondente (“Medical Dictionary for Regulatory Activities”). A abordagem com melhor desempenho na tarefa 1a foi um modelo BERTweet large treinado com dados gerados através de um processo de data augmentation. Relativamente à tarefa 1b, os melhores resultados foram obtidos usando um modelo RoBERTa large com dados de treino sobreamostrados. Na tarefa 1c utilizou-se um modelo RoBERTa base treinado com dados adicionais provenientes de um conjunto de dados externo. A abordagem utilizada na terceira tarefa não conseguiu alcançar resultados relevantes (F1 de 0.12), enquanto que os sistemas desenvolvidos para as duas primeiras alcançaram resultados ao nível dos melhores do desafio (F1 de 0.69 e 0.66 respetivamente).Mestrado em Engenharia Informátic

Utilizing Multi-level Classification Techniques to Predict Adverse Drug Effects and Reactions

Multi-class classification models are used to predict categorical response variables with more than two possible outcomes. A collection of multi-class classification techniques such as Multinomial Logistic Regression, Na\ {i}ve Bayes, and Support Vector Machine is used in predicting patients’ drug reactions and adverse drug effects based on patients’ demographic and drug administration. The newly released 2018 data on drug reactions and adverse drug effects from U.S. Food and Drug Administration are tested with the models. The applicability of model evaluation measures such as sensitivity, specificity and prediction accuracy in multi-class settings, are also discussed

Normalizing Spontaneous Reports into MedDRA: some Experiments with MagiCoder

Text normalization into medical dictionaries is useful to support clinical task. A typical setting is Pharmacovigilance (PV). The manual detection of suspected adverse drug reactions (ADRs) in narrative reports is time consuming and Natural Language Processing (NLP) provides a concrete help to PV experts. In this paper we carry on experiments for testing performances of MagiCoder, an NLP application designed to extract MedDRA terms from narrative clinical text. Given a narrative description, MagiCoder proposes an automatic encoding. The pharmacologist reviews, (possibly) corrects, and then validates the solution. This drastically reduces the time needed for the validation of reports with respect to a completely manual encoding. In previous work we mainly tested MagiCoder performances on Italian written spontaneous reports. In this paper, we include some new features, change the experiment design, and carry on more tests about MagiCoder. Moreover, we do a change of language, moving to English documents. In particular, we tested MagiCoder on the CADEC dataset, a corpus of manually annotated posts about ADRs collected from social media

Biomedical Information Extraction Pipelines for Public Health in the Age of Deep Learning

abstract: Unstructured texts containing biomedical information from sources such as electronic health records, scientific literature, discussion forums, and social media offer an opportunity to extract information for a wide range of applications in biomedical informatics. Building scalable and efficient pipelines for natural language processing and extraction of biomedical information plays an important role in the implementation and adoption of applications in areas such as public health. Advancements in machine learning and deep learning techniques have enabled rapid development of such pipelines. This dissertation presents entity extraction pipelines for two public health applications: virus phylogeography and pharmacovigilance. For virus phylogeography, geographical locations are extracted from biomedical scientific texts for metadata enrichment in the GenBank database containing 2.9 million virus nucleotide sequences. For pharmacovigilance, tools are developed to extract adverse drug reactions from social media posts to open avenues for post-market drug surveillance from non-traditional sources. Across these pipelines, high variance is observed in extraction performance among the entities of interest while using state-of-the-art neural network architectures. To explain the variation, linguistic measures are proposed to serve as indicators for entity extraction performance and to provide deeper insight into the domain complexity and the challenges associated with entity extraction. For both the phylogeography and pharmacovigilance pipelines presented in this work the annotated datasets and applications are open source and freely available to the public to foster further research in public health.Dissertation/ThesisDoctoral Dissertation Biomedical Informatics 201