key: cord-0713704-cq73ux29
authors: Usuzaki, Takuma; Chiba, Shuji; Shimoyama, Minoru
title: How can we evaluate an interrelation of symptoms?
date: 2020-05-07
journal: Arch Gerontol Geriatr
DOI: 10.1016/j.archger.2020.104096
sha: 4dfe7eb0eb56b7ac2f4bc24ac79d0f64888a2b08
doc_id: 713704
cord_uid: cq73ux29

A pandemic of 2019 novel coronavirus (COVID-19) is an international problem and factors associated with increased risk of mortality have been reported. However, there exists limited statistical method to estimate a comprehensive risk for a case in which a patient has several characteristics and symptoms concurrently. We applied Boolean Monte Carlo method (BMCM) to the Novel Corona Virus 2019 Dataset to determine interrelation of patient's characteristics and symptoms. In the analyses, age, fever as an onset symptom, and sex were used as explanatory variables, and death as the objective variable. Among 265 patients included in the analysis, the interrelations for estimating death were determined as age "and" fever "and" sex (p < 0.0001 for both operators). This result indicates that satisfying the three conditions of age, fever, and sex concurrently may be associated with an increased risk of mortality.

years using Mann-Whitney U test. They found that symptoms tended to continue in older than 80 years group and older than 80 years groups had higher risk of severity compared with other groups. They concluded that the COVID-19 infection in older patients was susceptible with a relatively high fatality rate. A variety of clinical symptoms, laboratory test results, and radiological manifestations have been reported for COVID-19 (Jin et al., 2020; Sohrabi et al., 2020) . Information on risk factors associated with mortality of COVID-19 have rapidly been accumulated. Older age, male sex, cardiovascular disease, diabetes, chronic respiratory disease, hypertension, and cancer have been found to be associated with an increased risk of mortality (Jordan et al., 2020) . As Niu et al. mentioned in their paper, elderly patients should be paid special attention because they may have typical or atypical presentations of infection and tend to have comorbidities. However, there exists limited statistical method to estimate a comprehensive risk for a case in which a patient has several characteristics and symptoms concurrently. i.e., we have a difficulty in evaluating an interrelation of patient's characteristics including comorbidities and symptoms in explaining outcome.

To evaluate an interrelation of patient's characteristics and symptoms we developed a method called the Boolean Monte Carlo method (BMCM) (Usuzaki et al., 2020) . In medicine, binary values (often represented by 0 and 1) are often used to represent patient characteristics, medical test results, and the presence of disease (positive or negative). Binary values can be calculated using Boolean operators (often represented by "and" and "or"), which can be regarded as an interrelation (Figure) . In BMCM, we randomly assign Boolean operators between binary variables and focus on the frequencies of operators that can explain outcomes correctly. By these processes, we can statistically determine interrelations of variables in explaining J o u r n a l P r e -p r o o f Table) , the interrelations for estimating death were determined as age "and" fever "and" sex (p < 0.0001 for both operators), i.e., satisfying the three conditions of age, fever, and sex concurrently may be associated with an increased risk of mortality. In this model, sensitivity and specificity were 25% and 89%, respectively. These results partly COVID-19 step-by-step could lead to overcoming. We sincerely hope for an end to this pandemic as soon as possible and we express our respect to all of those working to overcome this situation.

The authors have no conflicts of interest to declare. 

Three examples of interrelations among X, Y, and Z in explaining A using a Venn diagram. (a), (b), and (c) correspond to interrelations A = X "and" Y "and" Z, A = X "and"

Y "or" Z, and A = X "or" Y "or" Z, respectively. 

Epidemiological, clinical and virological characteristics of 74 cases of coronavirusinfected disease 2019 (COVID-19) with gastrointestinal symptoms

Covid-19: risk factors for severe disease and death

Clinical characteristics of older patients infected with COVID-19: A descriptive study

Agha, R., 2020. World Health Organization declares global emergency: A review of the

We express our sincere thanks to Johns Hopkins University and related organizations for making the data available for educational and academic research purposes.