Relationship of clinical course of illness variables to medical comorbidities in 900 adult outpatients with bipolar disorder.

Background: Medical illnesses are highly comorbid with bipolar disorder, but their relationship to illness characteristics has not been previously delineated.

Methods: The incidence of 34 medical conditions and 6 poor prognosis factors (PPFs) was derived from answers to a questionnaire in over 900 outpatients with bipolar disorder who gave informed consent. The relationship of PPFs to the number of medical comorbidities was examined by Mann-Whitney U, Pearson r, and logistic regression.

Results: When examined individually, each of the 6 PPFs associated with an adverse course of bipolar disorder was significantly related to the number of medical comorbidities patients had. When age, gender, and independence of their relationships to each other were controlled for via regression, 3 of the PPFs remained significant (anxiety disorder, childhood abuse, and age of onset), and having 20 or more prior episodes was a strong trend. The number of PPFs was correlated with the number of comorbidities, although the above 3 PPFs show a similar magnitude of relationship.

Conclusion: A history of childhood adversity, early age of onset of bipolar disorder, and an anxiety comorbidity were independently related to the number of medical comorbidities that patients experienced as adults. While the nature and mechanisms of this linkage remain to be further explored, the findings indicate the need for greater attention to and treatment of these 3 PPFs in hopes of ameliorating both the adverse course of bipolar illness and the burden of medical comorbidities with which they are associated.