Table 5. Factors affecting length of stay in patients with LGIB who underwent colonoscopy.

Variable	Time Ratio	Lower 95 % CI	Upper 95 % CI	P value
Late colonoscopy	Referent
Early Colonoscopy ( < 24 h)	0.68	0.68	0.68	< 0.001
Early Colonoscopy ( < 24 h) [exact-matched] 1	0.64	0.63	0.65	< 0.001
No EGD	Referent
Early EGD	0.87	0.87	0.88	< 0.001
Late EGD	0.96	0.96	0.97	< 0.001
Age (per decade-increase)	1.05	1.048	1.053	< 0.001
Female	1.05	1.045	1.056	< 0.001
Weekend admission	0.99	0.980	0.991	< 0.001
CCI	1.04	1.036	1.039	< 0.001
AKI	1.20	1.19	1.21	< 0.001
Colectomy/colostomy in same admission	2.38	2.34	2.43	< 0.001
ICU admission	1.67	1.59	1.75	< 0.001
PRBC transfusion	1.06	1.05	1.07	< 0.001
Insurance
Medicare	Referent
Medicaid	1.04	1.03	1.05	< 0.001
Private	0.95	0.94	0.95	< 0.001
Self-pay	0.98	0.96	0.99	0.006
No charge	1.00	0.96	1.04	0.808
Other	1.00	0.98	1.02	0.709
Hospital region
Northeast	Referent
Midwest	0.94	0.93	0.95	< 0.001
South	0.96	0.95	0.97	< 0.001
West	0.86	0.85	0.87	< 0.001
Hospital location/teaching status
Rural	Referent
Urban non-teaching	1.05	1.04	1.07	< 0.001
Urban teaching	1.06	1.05	1.08	< 0.001
Hospital bed size
Small	Referent
Medium	1.04	1.03	1.05	< 0.001
Large	1.08	1.06	1.09	< 0.001

Analysis N = 794,455. Geometric mean length of stay: 3.5 days.

Area under the curve: 0.774

Time ratios reflect % change over the geometric mean length of stay

LGIB, lower gastrointestinal bleeding; CI, confidence interval; EGD, esophagogastroduodenoscopy; CCI, Charlson Comorbidity Index; ICU, intensive care unit.

These results are derived from multivariable analysis using mixed-effects accelerated-failure-time (AFT) model with log-normal distribution.

¹ Exact-matched analysis on variables marked ¹ in Table 1 and on number of diagnostic/operative procedures (in addition to colonoscopy), yielding 14,903 matched observations (early colonoscopies n = 7,606), among 5,309 matching strata.