Global coronavirus disease 2019: what has daily cumulative index taught us?

Lai, Chih-Cheng; Wang, Cheng-Yi; Wang, Ya-Hui; Hsueh, Po-Ren

ABSTRACT In addition to the absolute case number, a rapid increase in the number of COVID-19 cases within a short time was supposed to result in insufficiency of the healthcare system and further negatively affect patients’ outcomes. This study was conducted to investigate the association between the outcomes of COVID-19 patients and daily cumulative index (DCI), which was defined as the average daily number of new cases of COVID-19 and calculated by cumulative cases/number of days between the first reported case and March 6, 2020 by country. Spearman's rank correlation analyses were conducted to evaluate the relationship between mortality, incidence, and DCI. In this study, we found that DCI was positively correlated with incidence (adjusted risk ratio [aRR] = 1.01, 95% [confidence interval, CI] = 1.00-1.02, p < 0.01). Higher correlation between mortality and DCI (mortality rate: r = 0.397, p = 0.018; mortality per 1,000,000 people: r = 0.0.428, p = 0.004) was observed than disease incidence. DCI remained statistically associated with mortality per 1,000,000 people after adjustment of Health Care Index (aRR = 1.02, 95% CI = 1.01-1.03, p < 0.001) or Healthcare Access and Quality Index (aRR = 1.02, 95% CI = 1.01-1.04, p < 0.01. Reducing DCI through strict infection control measures can help slow the increasing number of COVID-19 cases and further improve outcome in COVID-19 patients.