A disheartening finding that has emerged from a study conducted by American and Swedish researchers is that the consequences of having bipolar disorder extend beyond the often life-altering symptoms. People suffering from the illness tend to die, on average, nine years prematurely, they reported online July 17 in JAMA Psychiatry.
The lead researcher was Casey Crump, M.D., Ph.D., a clinical assistant professor of medicine at Stanford University.
The focus of the study was an entire adult population—about 7 million individuals—who were living in Sweden in 2003, about 6,600 of whom had been diagnosed with bipolar disorder. Casey and his colleagues used the complete inpatient and outpatient records for this cohort over the next seven years to evaluate the other medical illnesses of those with bipolar disorder and to see how the death rates of those with bipolar disorder compared with the death rates of those without the illness.
The subjects with bipolar disorder had twice the death rate of the general Swedish population and died, on average, nine-years earlier than the rest of the population, the researchers found. Women with bipolar disorder died at the average age of 73, whereas women in the general population died at the average age of 83. Men with bipolar died at the average age of 72, while men in the general population died at the average age of 78.
The premature death rate of bipolar patients was attributable to multiple causes.
For example, compared with the general population and after age and other sociodemographic factors were considered, both women and men with bipolar disorder had an increased risk of death from heart disease, diabetes, chronic obstructive pulmonary disease (COPD), flu, or pneumonia. The odds were highest for death from flu or pneumonia (fourfold for both women and men), diabetes (fourfold for women and threefold for men), and COPD (threefold for both genders).
In addition, women with bipolar disorder had a significantly increased mortality from stroke (threefold) and colon cancer (twofold). And the risk of death from suicide was tenfold among women and eightfold among men with bipolar disorder.
However, the researchers also found that whereas bipolar subjects’ highest odds of dying prematurely were from suicide, their leading causes of death were cardiovascular disease and cancer, as in the general population.
But when bipolar patients with cardiovascular disease, cancer, COPD, or diabetes received timely medical care for such illnesses, they tended to not die any earlier from them than did the general population. “This finding suggests that better delivery of primary health care can effectively reduce early mortality among people with bipolar disorder,” Crump said in an interview with Psychiatric News. “Regular follow-up with primary, preventive health care is a critical part of managing bipolar disorder and its health consequences,” he emphasized.
The researchers also assessed whether psychotropic medication use by bipolar subjects had any association with their mortality, and they noted that their data pointed to such a link. For example, compared with bipolar subjects who used only lithium, bipolar subjects who used carbamazepine, risperidone, or valproic acid either alone or with another medication had a modestly increased death rate. The same held for those who used olanzapine solely. In contrast, those bipolar patients who took quetiapine or lamotrigine either alone or with some other medication had significantly reduced mortality compared with those who used only lithium.
In addition, bipolar patients who used none of these medications had a twofold increase in all-cause mortality and in suicide mortality compared with patients who used such medications.
These findings are “consistent with previous evidence suggesting that pharmacologic treatment of bipolar disorder may reduce not only suicide risk, but also premature mortality from natural causes,” the researchers said in their report. Yet “these findings should be interpreted with caution because of possible confounding by disease severity or other unmeasured factors and because few patients received monotherapy, and precision was limited for specific medications.”
This appears to be the first study to examine the association between bipolar disorder and mortality using complete outpatient and inpatient diagnoses for an entire national population. Previous studies have relied mainly on hospital-discharge data or case-control data. Thus comprehensiveness is one of the strengths of the study. Yet information about smoking, exercise, obesity, and other lifestyle factors that could have impacted mortality was not available for the study population. This was a weakness of the study, the researchers noted.
The study was funded by the National Institute on Drug Abuse and by an Agreement on Medical Training and Research project grant from Lund, Sweden. ■