Factors and Economic Outcomes Associated with Documented Difficult Intubation in the United States

Figures & data

Table 1 Patient and Hospital Demographic Characteristics and Logistic Regression Outputs Prior to Risk Adjustment Matching

Patient Characteristics	Without Difficult Intubation		With Difficult Intubation		p-value^a	Comparing Difficult Intubation to No Difficult Intubation
	2,233,142		609
	Number of Patients	Percent of Patients	Number of Patients	Percent of Patients		Odds Ratio	95% Confidence Limits		p-value^a
Age Category
< 65 years	1,166,440	52%	347	57%	0.019	N/A			N/A
≥ 65 years	1,066,702	48%	262	43%		0.841	0.666	1.062	0.1454
						Reference group=Age<65
Gender
Male	1,009,182	45%	358	59%	<0.0001	1.652	1.396	1.953	<0.0001
Female	1,223,960	55%	251	41%		N/A	N/A	N/A	N/A
						Reference group=Female
Race
Black	226,988	10%	125	21%	<0.0001	2.069	1.679	2.551	<0.0001
White	1,775,839	80%	422	69%		N/A	N/A	N/A	N/A
Other	192,258	9%	52	9%		1.062	0.792	1.424	0.6894
Unspecified	38,057	2%	10	2%		1.01	0.538	1.895	0.9748
						Reference group=White
Insurance Type
Medicaid	213,795	10%	74	12%	0.004	1.103	0.808	1.505	0.538
Managed Care	746,579	33%	183	30%		1.045	0.815	1.339	0.7294
Uninsured	71,561	3%	32	5%		1.562	1.032	2.363	0.0349
Other ins	90,998	4%	29	5%		1.162	0.775	1.742	0.4684
Medicare	1,110,209	50%	291	48%		N/A	N/A	N/A	N/A
						Reference group=Managed care
Admission Type
Elective	1,361,309	61%	279	46%	<0.0001	N/A	N/A	N/A	N/A
Urgent/Emergent	871,833	39%	330	54%		1.587	1.335	1.886	<0.0001
						Reference group=Elective
Hospital Characteristics						Hospital Characteristics
Hospital Region
South	1,060,938	48%	303	50%	0.006	N/A	N/A	N/A	N/A
Northeast	280,004	13%	63	10%		0.862	0.647	1.147	0.3072
Midwest	516,277	23%	117	19%		0.868	0.696	1.083	0.2089
West	375,923	17%	126	21%		1.52	1.221	1.893	0.0002
						Reference group=South
Teaching Hospital
Teaching Hospital	1,039,632	47%	331	54%	0.0001	1.107	0.914	1.34	0.2981
Non-Teaching Hospital	1,193,510	53%	278	46%		N/A	N/A	N/A	N/A
						Reference group=Teaching Hospital
Bed Size
500+ beds	777,012	35%	305	50%	<0.0001	1.567	1.25	1.965	<0.0001
300–500	671,676	30%	147	24%		0.94	0.746	1.185	0.6014
<300	784,454	35%	157	26%		N/A	N/A	N/A	N/A
						Reference group=<300
Urban vs Rural
Urban	2,004,270	90%	558	92%	0.127	1.038	0.774	1.393	0.8038
Rural	228,872	10%	51	8%		N/A	N/A	N/A	N/A
						Reference group=Urban

Note: ^aChi-square test was used to calculate p-value.

Abbreviation: N/A, not applicable.

Figure 1 Patient selection criteria for inclusion in the study.

Abbreviations: DI, difficult intubation; MDC, major diagnostic category; OR, operating room.

Table 2 Distribution of Comorbidities for Patients with and without Difficult Intubation Prior to Risk Adjustment Matching

Patient Comorbidities	Number of Patients without Difficult Intubation	Percent of Patients without Difficult Intubation	Number of Patients with Difficult Intubation	Percent of Patients with Difficult Intubation	p-value^a	Odds Ratio^b	Lower 95% Confidence Limits	Upper 95% Confidence Limits	p-value^a
Obesity	582,344	26%	265	44%	<0.0001	2.202	1.857	2.612	<0.0001
Cancer	190,379	9%	86	14%	<0.0001	1.886	1.458	2.44	<0.0001
Acquired Immune Deficiency Disease	2,484	0%	2	0%	0.108	1.654	0.41	6.67	0.4796
Congestive Heart Failure	265,728	12%	135	22%	<0.0001	1.236	0.989	1.545	0.0621
Chronic Obstructive Pulmonary Disease	408,685	18%	176	29%	<0.0001	1.553	1.295	1.861	<0.0001
Cardiovascular Disease	107,398	5%	55	9%	<0.0001	1.419	1.054	1.911	0.0211
Diabetes	447,307	20%	177	29%	<0.0001	1.146	0.954	1.378	0.145
Diabetes with Sequela	178,372	8%	107	18%	<0.0001	1.432	1.109	1.849	0.006
Hypertension	1,389,328	62%	452	74%	<0.0001	1.3	1.061	1.592	0.0114
Metastatic Solid Tumor	49,571	2%	24	4%	0.0039	1.123	0.712	1.772	0.6183
Myocardial Infarction	223,036	10%	94	15%	<0.0001	0.988	0.777	1.255	0.9201
Peripheral Vascular Disease	173,699	8%	83	14%	<0.0001	1.289	1.007	1.649	0.0439
Renal Disease	250,842	11%	120	20%	<0.0001	1.048	0.815	1.348	0.7135
Mild Liver Disease	79,086	4%	38	6%	0.0003	1.157	0.811	1.651	0.422
Moderate/Severe Liver Disease	9,014	0%	10	2%	<0.0001	2.344	1.193	4.606	0.0134
Paralysis	30,879	1%	20	3%	<0.0001	1.435	0.896	2.298	0.1332
Dementia	61,454	3%	16	3%	0.8509	0.919	0.553	1.527	0.7431

Notes: ^aChi-square test was used to calculate p-value. ^bReference group for comorbidity odds ratio is patients without the comorbidity for each comorbid condition.

Table 3 Cost and Utilization Differences Between Patients with and without Difficult Intubation Before and After Risk Adjustment

Before Risk Adjustment
	Difficult Intubation						No Difficult Intubation
	N	Mean	ICU Admission Rate	95% Lower CI	95% Upper CI	STD	N	Mean	ICU Admission Rate	95% Lower CI	95% Upper CI	STD	p-value	Mean Difference
Admission Cost (US Dollars)	609	$45,251	–	$41,780	$48,722	$43,613	2,233,142	$22,056	–	$22,020	$22,091	$27,008	<0.0001	$23,196
Admission Length of Stay (Days)	609	10.7	60%	9.7	11.7	12.1	2,233,142	4.5	16%	4.5	4.5	5.8	<0.0001	6.2
ICU Cost (US Dollars)	367	$11,657	–	$10,051	$13,264	$15,653	358,359	$7,049	–	$7,018	$7,079	$9,386	<0.0001	$4,609
ICU Length of Stay (Days)	367	5.4	–	4.8	6.0	5.8	358,359	3.4	–	3.3	3.4	3.9	<0.0001	2.0
After Risk Adjustment
	Difficult Intubation						No Difficult Intubation
	N	Mean	ICU Admission Rate	95% Lower CI	95% Upper CI	STD	N	Mean	ICU Admission Rate	95% Lower CI	95% Upper CI	STD	p-value	Mean Difference
Admission Cost (US Dollars)	606	$45,233	–	$41,748	$48,717	$43,679	606	$30,765	–	$28,242	$33,288	$31,624	<0.0001	$14,468
Admission Length of Stay (Days)	606	10.7	60%	9.8	11.7	12.1	606	6.9	33%	6.3	7.5	7.7	<0.0001	3.8
ICU Cost (US Dollars)	364	$11,662	–	$10,043	$13,280	$15,702	198	$7,633	–	$6,393	$8,873	$8,849	0.0001	$4,029
ICU Length of Stay (Days)	364	5.4		4.8	6.0	5.8	198	3.4		2.9	4.0	3.8	<0.0001	2.0

Notes: ICU admission rate, cost (US dollars), and length of stay (days) are reported for patients who had an ICU admission 0–2 days after the primary surgery.

Abbreviations: CI, confidence interval; ICU, intensive care unit; N, number of patients; STD, standard deviation.

Table 4 Demographic Characteristics of Patients with Difficult Intubation Hospital Inpatient Admissions for Patients After Risk Adjustment Matching

Patient Characteristics	Without Difficult Intubation		With Difficult Intubation		p-value^a	Comparing Difficult Intubation to No Difficult Intubation
	606		606				95% Confidence Limits
	Number of Patients	Percent of Patients	Number of Patients	Percent of Patients		Odds Ratio	Lower Limit	Upper Limit	p-value^a
Age Category
< 65 years	324	53%	346	57%	0.204	N/A			N/A
≥ 65 years	282	47%	260	43%		0.948	0.676	1.331	0.7591
						Reference group=Age<65
Gender
Male	359	59%	356	59%	0.861	0.994	0.783	1.262	0.9595
Female	247	41%	250	41%		N/A	N/A	N/A	N/A
						Reference group=Female
Race
Black	114	19%	125	21%	0.691	1.162	0.854	1.582	0.3384
White	437	72%	420	69%		N/A	N/A	N/A	N/A
Other	48	8%	51	8%		1.145	0.738	1.775	0.5456
Unspecified	7	1%	10	2%		1.453	0.532	3.971	0.4661
						Reference group=White
Insurance Type
Medicaid	87	14%	74	12%	0.293	0.822	0.528	1.279	0.3856
Managed Care	149	25%	182	30%		1.192	0.832	1.709	0.3392
Uninsured	34	6%	32	5%		0.958	0.534	1.72	0.8863
Other ins	29	5%	29	5%		1.036	0.578	1.855	0.9065
Medicare	307	51%	289	48%		N/A	N/A	N/A	N/A
						Reference group=Managed care
Admission Type
Elective	272	45%	277	46%	0.773	N/A	N/A	N/A	N/A
Urgent/Emergent	334	55%	329	54%		0.951	0.743	1.217	0.688
						Reference group=Elective
Hospital Characteristics
Hospital Region
South	325	54%	301	50%	0.495	N/A	N/A	N/A	N/A
Northeast	59	10%	62	10%		1.178	0.771	1.802	0.4486
Midwest	100	17%	117	19%		1.287	0.926	1.788	0.1338
West	122	20%	126	21%		1.126	0.821	1.545	0.462
						Reference group=South
Teaching Hospital
Teaching Hospital	347	57%	330	54%	0.325	0.884	0.667	1.17	0.3869
Non-Teaching Hospital	259	43%	276	46%		N/A	N/A	N/A	N/A
						Reference group=Teaching
Bed Size
500+ beds	319	53%	303	50%	0.638	1.027	0.735	1.435	0.8758
300–500	141	23%	146	24%		0.99	0.705	1.39	0.9526
<300	146	24%	157	26%		N/A	N/A	N/A	N/A
						Reference group=<300
Urban vs Rural
Urban	558	92%	555	92%	0.753	0.939	0.609	1.447	0.7753
Rural	48	8%	51	8%		N/A	N/A	N/A	N/A
						Reference group=Urban

Note: ^aChi-square test was used to calculate p-value.

Abbreviation: N/A, not applicable.

Table 5 Patient and Hospital Demographic Characteristics and Logistic Regression Outputs After Risk Adjustment Matching

Patient Comorbidities	Number of Patients without Difficult Intubation	Percent of Patients without Difficult Intubation	Number of Patients with Difficult Intubation	Percent of Patients with Difficult Intubation	p-value^a	Odds Ratio^b	Lower 95% Confidence Limits	Upper 95% Confidence Limits	p-value^a
Obesity	217	36%	264	44%	0.0058	1.251	0.975	1.606	0.0781
Cancer	97	16%	86	14%	0.3775	0.96	0.665	1.386	0.8268
Acquired Immune Deficiency Disease	-	0%	2	0%	0.157	N/A	N/A	N/A	0.9794
Congestive Heart Failure	119	20%	133	22%	0.3217	1.16	0.845	1.594	0.3579
Chronic Obstructive Pulmonary Disease	180	30%	175	29%	0.7523	0.948	0.73	1.232	0.6907
Cardiovascular Disease	59	10%	54	9%	0.6213	0.877	0.571	1.35	0.5518
Diabetes	147	24%	176	29%	0.0596	1.201	0.909	1.587	0.1979
Diabetes with Sequela	85	14%	106	17%	0.0978	1.242	0.843	1.828	0.2727
Hypertension	447	74%	450	74%	0.8442	0.947	0.707	1.268	0.7141
Metastatic Solid Tumor	32	5%	24	4%	0.2737	0.788	0.424	1.465	0.4517
Myocardial Infarction	85	14%	94	16%	0.4662	1.109	0.788	1.562	0.553
Peripheral Vascular Disease	92	15%	83	14%	0.462	0.87	0.614	1.232	0.4315
Renal Disease	116	19%	120	20%	0.7717	0.915	0.642	1.304	0.6234
Mild Liver Disease	35	6%	38	6%	0.7172	1.244	0.724	2.14	0.429
Moderate/Severe Liver Disease	16	3%	10	2%	0.2342	0.556	0.226	1.365	0.2003
Paralysis	19	3%	20	3%	0.8707	1.188	0.583	2.418	0.6358
Dementia	19	3%	16	3%	0.6068	0.918	0.449	1.878	0.8145

Notes: ^aChi-square test was used to calculate p-value. ^bReference group for comorbidity odds ratio is patients without the comorbidity for each comorbid condition.

Abbreviation: N/A, not applicable.