In epidemiology, the death rate of specific cases is calculated by dividing the deaths from a cause by the number at risk case fatality rate.
The number of fatalities from a specified disease in a given period per 100 episodes of the disease arising in the same period. Unless all such deaths occur rapidly after the onset of the disease (e.g. cholera) they are likely to be the outcome of episodes that started in an earlier period (hence the term ratio rather than rate). Comparison of the annual number of admissions and fatalities in a given hospital in respect of a specific disease is known as the hospital fatality ratio.