Table 1. Demographic characteristics and comorbidities in bipolar disorder inpatients.

The proportion of non-bipolar disorder and bipolar disorder inpatients were obtained using cross-tabulation. Significant P-values ≤0.01 at 95% confidence interval. Odds ratio generated by the logistic regression model and adjusted for age, gender and race.

MDD, major depressive disorder; ADHD, attention-deficit/hyperactivity disorder; PTSD, post-traumatic stress disorder

Variables	Non-bipolar disorder	Bipolar disorder	Odds ratio	95% Confidence interval	P-value
Total inpatients	27250255	316025	-	-	-
Age at admission, %
18 – 34 years	19.5	36.4	6.43	6.33–6.53	< 0.001
35 – 50 years	15.6	32.8	6.81	6.71–6.91	< 0.001
51 – 64 years	22.7	22.7	3.91	3.85–3.97	< 0.001
+65 years	42.2	8.0	Reference
Sex, %
Male	40.9	42.3	1.11	1.10–1.12	< 0.001
Female	59.1	57.7	Reference
Race, %
Caucasian	68.7	72.6	Reference
African American	14.7	14.7	0.81	0.79–0.82	< 0.001
Hispanic	10.6	8.0	0.65	0.64–0.66	< 0.001
Other	6.1	4.6	0.72	0.71–0.73	< 0.001
Psychiatric comorbidities, in %
No comorbidities	-	-	Reference
MDD	1.2	1.6	0.51	0.49–0.52	< 0.001
Anxiety	10.3	31.8	2.10	2.08–2.12	< 0.001
ADHD	0.5	5.2	3.06	2.99–3.11	< 0.001
Borderline personality	0.2	6.9	6.93	6.81–7.07	< 0.001
PTSD	0.8	10.1	2.44	2.39–2.47	< 0.001
Alcohol abuse	4.7	18.3	1.94	1.92–1.96	< 0.001
Drug abuse	4.7	33.5	4.33	4.29–4.37	< 0.001
Medical comorbidities, in %
No comorbidities	-	-	Reference
Diabetes	19.1	11.2	0.96	0.95–0.97	< 0.001
Hypertension	50.5	31.1	0.86	0.85–0.87	< 0.001
Obesity	13.4	11.1	0.82	0.81–0.83	< 0.001
Asthma	6.6	11.7	1.37	1.35–1.38	< 0.001
Rheumatoid arthritis	2.9	1.4	0.64	0.63–0.66	< 0.001
Hypothyroidism	12.0	11.0	1.59	1.58–1.62	< 0.001
Migraine	2.6	5.5	1.23	1.21–1.25	< 0.001
Multiple sclerosis	0.4	0.4	0.82	0.77–0.87	< 0.001