In addition, patients with BD are three times more likely to die prematurely of all causes, compared with the general population, with alcohol-related diseases contributing to more premature deaths than cardiovascular disease (CVD), diabetes, and cancer.
The study results emphasize the need for personalized approaches to risk prediction and prevention of premature cause-specific mortality over the life-course of individuals with BD, lead investigator Tapio Paljärvi, PhD, an epidemiologist at Niuvanniemi Hospital in Kuopio, Finland, told this news organization.
The findings were published online in BMJ Mental Health.
Alcohol a major contributor to early death
A number of studies have established that those with BD have twice the risk of dying prematurely, compared with those without the disorder.
To learn more about the factors contributing to early death in this patient population, the investigators analyzed data from nationwide Finnish medical and insurance registries. They identified and tracked the health of 47,000 patients, aged 15-64 years, with BD between 2004 and 2018.
The average age at the beginning of the monitoring period was 38 years, and 57% of the cohort were women.
To determine the excess deaths directly attributable to BD, the researchers compared the ratio of deaths observed over the monitoring period in those with BD to the number expected to die in the general population, also known as the standard mortality ratio.
Of the group with BD, 3,300 died during the monitoring period. The average age at death was 50, and almost two-thirds (65%, or 2,137) of those who died were men.
Investigators grouped excess deaths in BD patients into two categories – somatic and external.
Of those with BD who died from somatic or disease-related causes, alcohol caused the highest rate of death (29%). The second-leading cause was heart disease and stroke (27%), followed by cancer (22%), respiratory diseases (4%), and diabetes (2%).
Among the 595 patients with BD who died because of alcohol consumption, liver disease was the leading cause of death (48%). The second cause was accidental alcohol poisoning (28%), followed by alcohol dependence (10%).
The leading cause of death from external causes in BD patients was suicide (58%, or 740), nearly half of which (48%) were from an overdose with prescribed psychotropic medications.
Overall, 64%, or 2,104, of the deaths in BD patients from any cause were considered excess deaths, that is, the number of deaths above those expected for those without BD of comparable age and sex.
Most of the excess deaths from somatic illness were either from alcohol-related causes (40%) – a rate three times higher than that of the general population – CVD (26%), or cancer (10%).
High suicide rate
When the team examined excess deaths from external causes, they found that 61% (651) were attributable to suicide, a rate eight times higher than that of the general population.
“In terms of absolute numbers, somatic causes of death represented the majority of all deaths in BD, as also reported in previous research,” Dr. Paljärvi said.
“However, this finding reflects the fact that in many high-income countries most of the deaths are due to somatic causes; with CVD, cancers, and diseases of the nervous system as the leading causes of death in the older age groups,” he added.
Dr. Paljärvi advised that clinicians treating patients with BD balance therapeutic response with potentially serious long-term medication side effects, to prevent premature deaths.
A stronger emphasis on identifying and treating comorbid substance abuse is also warranted, he noted.
Dr. Paljärvi noted that the underlying causes of the excess somatic mortality in people with BD are not fully understood, but may result from the “complex interaction between various established risk factors, including tobacco use, alcohol abuse, physical inactivity, unhealthy diet, obesity, hypertension, etc.”
Regarding the generalizability of the findings, he said many previous studies have been based only on inpatient data and noted that the current study included individuals from various sources including inpatient and outpatient registries as well as social insurance registries.
“While the reported excess all-cause mortality rates are strikingly similar across populations globally, there is a paucity of more detailed cause-specific analyses of excess mortality in BD,” said Dr. Paljärvi, adding that these findings should be replicated in other countries, including the United States.