Using multiple-cause-of-death data as a complement of underlying-cause-of-death data in examining mortality differences in psychiatric disorders between countries

Background Little is known about the mortality differences in psychiatric disorders (PD) between countries according to multiple-cause-of-death (MCOD) data. Objective To compare mortality differences in PD between Taiwan and the US according to MCOD and underlying-cause-of-death (UCOD) data and factors associated with the reporting of PD and assigning PD as the UCOD. Method MCOD data of Taiwan and the US for years 2003 through 2005 were used for analysis. Deaths per 100,000 population for various PD by age and sex were calculated for each country. Mortality rate ratios between Taiwan and the US were computed to examine the extent of mortality differences between the countries. Odds ratios in reporting PD and assigning PD as the UCOD by age and sex for each country were estimated according logistic regression model. Results According to UCOD data, the PD mortality was 3.6 per 100,000 population in Taiwan and 21.9 per 100,000 population in the US, a sixfold difference. The mortality differences increased according to MCOD, which was 10.3 per 100,000 population in Taiwan and 115.4 per 100,000 population in the US, an 11-fold difference. Exception dementia/Alzheimer’s disease, the mortality differences between the countries increased in schizophrenia, mood disorder/depression, use of alcohol and use of drug according to MCOD data compared with those according to UCOD data. The percentage in reporting PD among all deaths in the US (13.9%) was higher than those in Taiwan (1.4%); however, the percentage in assigning PD as the UCOD in Taiwan (35%) was higher than those in the US (19%). Conclusion MCOD data could be used as a complement to UCOD data to provide more information (such as percentage of reporting PD and assigning PD as the UCOD) in interpreting mortality differences in PD between the countries