Bipolar I most recent episode-manic (BP-I-M) is an important cause of morbidity and mortality in hospitalized patients. While BP-I-M has been extensively studied in the past, the contemporary data for impact of BP-I-M on cost of hospitalization are largely lacking.

We queried the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample (HCUP-NIS) dataset between 1998–2011 using the ICD-9 codes. Severity of comorbid conditions was defined by Deyo modification of Charlson comorbidity index. Primary outcome was in-hospital mortality and secondary outcome was total charges for hospitalization. Using SAS 9.2, Chi2 test, t-test and Cochran-Armitage test were used to test significance.

A total of 10,875 patients were analyzed; 57.13% were female and 42.87% were male (P < 0.0001); 74.78% were white, 14.51% black and 10.71% of other race (P < 0.0001). Rate of hospitalization increased from 528.71/million to 588.76/million from 1998–2011. Overall mortality was 0.42% and mean cost of hospitalization was 22,215.77$. The in-hospital mortality increased from 0.37% to 0.82% (P < 0.0001) and mean cost of hospitalization increased from 10,580.54$ to 40,737.65$. Total spending on BP-I-M related admissions have increased from $44.24 million/year to $187.00 million/year.

While mortality has slightly decreased from 1998 to 2011, the cost has significantly increased from $44.24 million/year to $187.00 million/year, which leads to an estimated $ 142.76 million/year additional burden to US health care system from. In the era of cost conscious care, preventing BP-I-M related hospitalization could save billions of dollars every year. Focused efforts are needed to establish preventive measures for BP-I-M related hospitalization.

The authors have not supplied their declaration of competing interest.