Using the Kano model to associate the number of confirmed cases of COVID-19 in a population of 100,000 with case fatality rates: an observational study (preprint)

ABSTRACT

Background: One of the key factors to understand the spread of COVID-19 is the case fatality rate(CFR) rates for counties/regions. However, many merely reported those CFRs on the basis of total confirmed cases(TCC) instead of per population of 100, 000. As such, the disparate definitions of CFR yield inconsistent results in COVID-19 situations. Whether both incident rate and the CFR can be indicators to identify a country/region hit by COVID-19 under(or out of) control is still unclear. This study aims to (1) develop a diagram to disperse both TCC and CFR on a population base of 100,000(namely TCC100 and CFR100, respectively) using the Kano model, (2)discuss selected countries/regions with success on preventative measures to keep COVID-19 under control(i.e., relatively lower TCC100 and CFR100 or CFR), and (3) design an app to display both TCC100 and CFR100 or CFR for all infected countries/regions.  Methods: We downloaded the COVID-19 data of confirmed cases and deaths in countries/regions on a daily basis from the Github website. Three values, TCC100, CFR100, and CFR, were computed for each country/region and displayed on the Kano model. The lower TCC100 and CFR values were deemed as having the COVID-19 situation more under control. An app was developed to display both TCC100 and CFR100 on Google Maps. Results: The correlation coefficient(CC) between TCC100 and CFR100 is 0.92(t=37.87) based on 285 count data (i.e., 12, 225, and 48 dispersed on the Kano diagram) obtained in comparison to the pair of TCC100 and CFR with the CC=-0.02(t=-0.25) and counts(i.e., 56, 145, and 84 on the Kano diagram). The state of Washington, USA, was found having the highest TCC100(=3498.15), CFR100 (=16548.96) and CFR(=5%) in comparison to (1)Taiwan[TCC100(=1.65), CFR100 (=2.17), CFR(=1%)] and (2)South Korea[TCC100(=20.34), CFR100 (=39.8), CFR(=2%)] on April 12,2020. Conclusion: We illustrated both TCC100 and CFR along with CFR100 to compare countries/regions on a Kano diagram to understand the COVID-19 situations better. A larger TCC100 value was strongly associated with a larger CFR100 value that needs further verifications in the future. An app was developed to display both TCC100 and CFR for countries/regions on a dashboard laid over Google Maps.