TOPLINE:

Among teens and adults with bipolar II disorder (BD-II), all-cause mortality was 60% higher than in those without the disorder and 24% higher than in those with bipolar I disorder (BD-I), a new study showed. Mortality was driven by both natural causes and unnatural causes such as suicide.

METHODOLOGY:

• A population-based, retrospective cohort study included more than 11,400 individuals (mean age, 40 years; 62% women) who were aged at least 12 years at the index BD-II diagnosis and had at least two psychiatrist-assigned BD-II diagnoses. The data were obtained from Taiwan’s National Health Insurance Database from 2000 to 2022.
• Participants with BD-II were individually age- and sex-matched to more than 45,700 control individuals without BD-II, with additional comparisons to more than 8000 unaffected biological siblings and nearly 180,000 patients with BD-I.
• The primary outcome was all-cause mortality; secondary outcomes were natural-cause mortality and unnatural-cause mortality.
• The analysis was adjusted for age, sex, income, urbanization level, psychiatric healthcare use, and comorbidity burden. The mean follow-up duration was 7.3 years.

TAKEAWAY:

• 1089 patients with BD-II and 1879 control individuals died during the follow-up period. The BD-II group had significantly higher risk for all-cause mortality than the matched control group (adjusted hazard ratio [aHR], 1.62; P < .001), as well as increased mortality for both natural causes (aHR, 1.37) and unnatural causes (aHR, 4.46).
• Patients with BD-II also had persistently higher all-cause mortality (aHR, 1.31) and unnatural-cause mortality (aHR, 2.05) than their unaffected siblings. Natural-cause mortality did not differ significantly between the groups.
• Compared to BD-I, BD-II was linked to higher all-cause and natural-cause mortality (aHRs, 1.24 and 1.45, respectively) but not unnatural-cause mortality.
• Unnatural-cause deaths in patients with BD-II were predominantly driven by suicide (aHR, 6.16), unintentional injuries (aHR, 2.81), and assault or homicide (aHR, 6.63).

IN PRACTICE:

“BD-II was associated with consistently elevated all-cause mortality across sex, age, and psychiatric comorbidity strata,” the investigators wrote.

“Collectively, these findings suggest the need for strengthened surveillance, targeted prevention, and proactive comprehensive psychiatric care, with emphasis on early treatment of BD-II,” they added.

SOURCE:

The study was led by Chih-Wei Hsu, MD, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan. It was published online on April 7 in JAMA Network Open.

LIMITATIONS:

The study lacked standardized ratings of mood symptom severity, measures of episode frequency, and covariates such as smoking, diet, and occupational exposures. The requirement for at least two psychiatrist-assigned codes rather than screening tool-based ascertainment may have led to exclusion of subthreshold cases. 

DISCLOSURES:

The study was funded by the Taiwan National Science and Technology Council. Disclosure information for the study investigators is available in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.