Time trends in mortality for people with severe mental illness in Denmark 2000-2018

People with a severe mental illness (SMI) have a marked reduction in life expectancy which is largely attributable to somatic morbidity. Life expectancy has increased in Global North populations, yet it remains unclear whether people with SMI have benefitted equally from this increase. Our objective was to explore time trends of all-cause and selected cause-specific mortality among all people in Denmark with registered diagnosis codes of SMI: depression, bipolar disorder, or schizophrenia at psychiatric out- and in-patient settings.

In consecutive yearly cohorts from 2000 to 2018, we examined all-cause and cause-specific mortality in all adults (aged ≥18) with and without diagnosis codes of SMI.

We found that all-cause mortality, and mortality from cardiovascular, cancer, respiratory, infections, trauma, and suicide were consistently elevated in those registered with SMI. While the crude all-cause mortality decreased substantially for all, also in people registered with SMI, after adjustment for sex and age, the mortality relative to people without SMI, remained unchanged or slightly increased for people registered with SMI, particularly among people registered with schizophrenia.

Despite a decrease in crude all-cause mortality, the consistently elevated mortality for people registered with SMI relative to the general population suggests that concerted efforts to reduce health inequity remain important.