ABSTRACT
Objective. To develop and validate a scale to stratify risk of 2-day mortality based on data collected during calls to an emergency dispatch center from patients with suspected coronavirus disease 2019 (COVID-19). Methods. Retrospective multicenter study of consecutive patients over the age of 18 years with suspected COVID-19 who were transported from home over the course of 3 months after telephone interviews with dispatchers. We analyzed clinical and epidemiologic variables and comorbidities in relation to death within 2 days of the call. Using data from the development cohort, we built a risk model by means of logistic regression analysis of categorical variables that were independently associated with 2-day mortality. The scale was validated first in a validation cohort in the same province and then in a cohort in a different province. Results. A total of 2320 patients were included. The mean age was 79 years, and 49.8% were women. The overall 2-day mortality rate was 22.6% (376 deaths of patients with severe acute respiratory syndrome coronavirus 2 infection). The model included the following factors: age, location (rural location as a protective factor), institutionalization, desaturation, lung sounds (rhonchi), and altered mental status. The area under the receiver operating characteristic curve for death within 2 days was 0.763 (95% CI, 0.725-0.802;P < .001). Mortality in patients at high risk (more than 2.4 points on the scale) was 60%. Conclusions. This risk scale derived from information available to an emergency dispatch center is applicable to patients with suspected COVID-19. It can stratify patients by risk of early death (within 2 days), possibly helping with decision making regarding whether to transport from home or what means of transport to use, and destination.
ABSTRACT
Opinion Mining (OM) is a field of Natural Language Processing (NLP) that aims to capture human sentiment in the given text. With the ever-spreading of online purchasing websites, micro-blogging sites, and social media platforms, OM in online social media platforms has picked the interest of thousands of scientific researchers. Because the reviews, tweets and blogs acquired from these social media networks, act as a significant source for enhancing the decision making process. The obtained textual data (reviews, tweets, or blogs) are classified into three different class labels which are negative, neutral and positive for analyzing and extracting relevant information from the given dataset. In this contribution, we introduce an innovative MapReduce improved weighted ID3 decision tree classification approach for OM, which consists mainly of three aspects: Firstly We have used several feature extractors to efficiently detect and capture the relevant data from the given tweets, including N-grams or character-level, Bag-Of-Words, word embedding (GloVe, Word2Vec), FastText, and TF-IDF. Secondly, we have applied a multiple feature selector to reduce the high feature’s dimensionality, including Chi-square, Gain Ratio, Information Gain, and Gini Index. Finally, we have employed the obtained features to carry out the classification task using an improved ID3 decision tree classifier, which aims to calculate the weighted information gain instead of information gain used in traditional ID3. In other words, to measure the weighted information gain for the current conditioned feature, we follow two steps: First, we compute the weighted correlation function of the current conditioned feature. Second, we multiply the obtained weighted correlation function by the information gain of this current conditioned feature. This work is implemented in a distributed environment using the Hadoop framework, with its programming framework MapReduce and its distributed file system HDFS. Its primary goal is to enhance the performance of a well-known ID3 classifier in terms of accuracy, execution time, and ability to handle the massive datasets. We have carried out several experiences that aims to assess the effectiveness of our suggested classifier compared to some other contributions chosen from the literature. The experimental results demonstrated that our ID3 classifier works better on COVID-19_Sentiments dataset than other classifiers in terms of Recall (85.72 %), specificity (86.51 %), error rate (11.18 %), false-positive rate (13.49 %), execution time (15.95s), kappa statistic (87.69 %), F1-score (85.54 %), classification rate (88.82 %), false-negative rate (14.28 %), precision rate (86.67 %), convergence (it convergent towards the iteration 90), stability (it is more stable with mean deviation standard equal to 0.12 %), and complexity (it requires much lower time and space computational complexity). CCBY