Multi-morbidity and frailty at death: A new classification of death records for an ageing world

Mortality statistics based on the underlying cause of death are challenged by increased life expectancy and a growing share of the population reaching ages associated with frequent multi-morbidity. Death, then, is likely to result from interactions between multiple diseases. This paper provides a novel way of analyzing causes of death. We account for all causes mentioned on death certificates and summarize this information along two dimensions that are emblematic of aging populations: multi-morbidity and frailty. We implement this classification to all deaths at age 50 and over in Italy in 2014. Multi-morbid processes represent the majority of morbid processes, rising from 43% at 50–54 to 63% at 85–89. Multi-morbidity at death is more frequent among males, although the age patterns of both genders are identical. About one in four deaths involve frailty symptoms, rising to 45% at age 95+. Mortality rates involving frailty are very similar for males and females