J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://www.jocmr.org

Original Article

Volume 13, Number 4, April 2021, pages 237-244

A Simplified Comorbidity Evaluation Predicting Clinical Outcomes Among Patients With Coronavirus Disease 2019

Figure 2. Using AUC to compare the performance accuracy of CCC, CCI, and ECI predictive of four different clinical outcomes. Panel A: Performance accuracy comparisons of hospital admission. Panel B: Performance accuracy comparisons of ICU. Panel C: Performance accuracy comparisons of patients receiving invasive mechanical ventilations. Panel D: Performance accuracy comparisons of in-hospital all-cause mortality. CCC: COVID-related high-risk chronic condition; CCI: Charlson Comorbidity Index; ECI: Elixhauser Comorbidity Index; ROC: receiver operating characteristics; ICU: intensive care unit; AUC: area under a receiver operating characteristic curve.

**Table 1.** Comparison of CCC, CCI, and ECI Comorbidity Evaluations
	CCC	CCI	ECI
CCCs (0 - 11): each chronic condition is equally weighted. CCI: obesity not listed in CCI (0 - 25); ECI (AHRQ algorithm, 0 - 34): coronary artery disease/myocardial infarction not listed in ECI, HIV/AIDS and diabetes with no complication were listed as “0”. ^aObesity was scored as -5 and hypertension was scored as -1 in the original ECI AHRQ algorithm. However, due to previous report of risks of obesity and hypertension in COVID-19 patients, to avoid the offset effect of other CCCs, we scored obesity and hypertension as 0 in this study. CCC: COVID-related high-risk chronic condition; CCI: Charlson Comorbidity Index; ECI: Elixhauser Comorbidity Index; HIV/AIDS: human immunodeficiency virus/acquired immunodeficiency syndrome; CHF: congestive heart failure; AHRQ: Agency for Healthcare Research and Quality; COVID-19: coronavirus disease 2019.
Active cancer	1	2	7
HIV/AIDS	1	6	0
Chronic obstructive pulmonary disease (COPD/asthma)	1	3	3
CHF	1	3	9
Hypertension	1	1	0^a
Coronary artery disease/myocardial infarction	1	1	(0)
Cerebrovascular accident (CVA)	1	1	5
Diabetes	1	3	0
Obesity	1	(0)	0^a
Chronic renal diseases	1	2	6
Liver cirrhosis	1	3	4

Table 1. Comparison of CCC, CCI, and ECI Comorbidity Evaluations

CCC

CCI

ECI

CCCs (0 - 11): each chronic condition is equally weighted. CCI: obesity not listed in CCI (0 - 25); ECI (AHRQ algorithm, 0 - 34): coronary artery disease/myocardial infarction not listed in ECI, HIV/AIDS and diabetes with no complication were listed as “0”. ^aObesity was scored as -5 and hypertension was scored as -1 in the original ECI AHRQ algorithm. However, due to previous report of risks of obesity and hypertension in COVID-19 patients, to avoid the offset effect of other CCCs, we scored obesity and hypertension as 0 in this study. CCC: COVID-related high-risk chronic condition; CCI: Charlson Comorbidity Index; ECI: Elixhauser Comorbidity Index; HIV/AIDS: human immunodeficiency virus/acquired immunodeficiency syndrome; CHF: congestive heart failure; AHRQ: Agency for Healthcare Research and Quality; COVID-19: coronavirus disease 2019.

Active cancer

HIV/AIDS

Chronic obstructive pulmonary disease (COPD/asthma)

CHF

Hypertension

0^a

Coronary artery disease/myocardial infarction

(0)

Cerebrovascular accident (CVA)

Diabetes

Obesity

(0)

0^a

Chronic renal diseases

Liver cirrhosis

**Table 2.** General Characteristics of Study Patient Population
	NHW	NHB	Hispanic	Others
*P < 0.05. NHW: non-Hispanic White; NHB: non-Hispanic Black; IQR: interquartile range; COVID-19: coronavirus disease 2019; ED: emergency department.
Patient visits, n (%)	29,410 (32.5)	30,022 (33.2)	26,109 (28.8)	5,008 (5.5)
Age (years), median (IQR)	46 (33, 57)	44 (30, 57)	41 (28, 54)	42 (29, 56)
Gender (male), n (%)	15,777 (53.7)	15,846 (52.8)	12,902 (49.4)	2,501 (49.9)
Number of COVID-19 tested at ED, n (%)	4,435 (16.8)	4,168 (13.9)	4,116 (15.8)	697 (13.9)
Number of COVID-19 positive, n (%)*	794 (15.3)	1,103 (24.7)	1,711 (37.5)	256 (33.9)
Among all COVID-19 positive patients, n	794	1,103	1,711	256
Age (years), median (IQR)*	53 (41, 62)	54 (42, 63)	50 (37, 61)	51 (38, 63)
Gender (male), n (%)*	463 (58.3)	540 (49.0)	826 (48.3)	127 (49.6)
Hospital admissions in COVID-19 patients, n (%)	393 (49.5)	519 (47.1)	823 (48.1)	116 (45.3)
ICU admissions among COVID-19 patients, n (%)	71 (8.9)	107 (9.7)	158 (9.2)	28 (10.9)
COVID-19 patients receiving ventilations, n (%)	47 (5.9)	65 (5.9)	107 (6.3)	19 (7.4)
In-hospital all-cause mortality, n (%)	39 (4.9)	54 (4.9)	67 (3.9)	17 (6.6)

Table 2. General Characteristics of Study Patient Population

NHW

NHB

Hispanic

Others

*P < 0.05. NHW: non-Hispanic White; NHB: non-Hispanic Black; IQR: interquartile range; COVID-19: coronavirus disease 2019; ED: emergency department.

Patient visits, n (%)

29,410 (32.5)

30,022 (33.2)

26,109 (28.8)

5,008 (5.5)

Age (years), median (IQR)

46 (33, 57)

44 (30, 57)

41 (28, 54)

42 (29, 56)

Gender (male), n (%)

15,777 (53.7)

15,846 (52.8)

12,902 (49.4)

2,501 (49.9)

Number of COVID-19 tested at ED, n (%)

4,435 (16.8)

4,168 (13.9)

4,116 (15.8)

697 (13.9)

Number of COVID-19 positive, n (%)*

794 (15.3)

1,103 (24.7)

1,711 (37.5)

256 (33.9)

Among all COVID-19 positive patients, n

794

1,103

1,711

256

Age (years), median (IQR)*

53 (41, 62)

54 (42, 63)

50 (37, 61)

51 (38, 63)

Gender (male), n (%)*

463 (58.3)

540 (49.0)

826 (48.3)

127 (49.6)

Hospital admissions in COVID-19 patients, n (%)

393 (49.5)

519 (47.1)

823 (48.1)

116 (45.3)

ICU admissions among COVID-19 patients, n (%)

71 (8.9)

107 (9.7)

158 (9.2)

28 (10.9)

COVID-19 patients receiving ventilations, n (%)

47 (5.9)

65 (5.9)

107 (6.3)

19 (7.4)

In-hospital all-cause mortality, n (%)

39 (4.9)

54 (4.9)

67 (3.9)

17 (6.6)

**Table 3.** Association Between Clinical Outcome and Number of CCCs Among COVID-19 Patients
	No CCC	One CCC	Two CCCs	≥ 3 CCCs	P value
COVID-19: coronavirus disease 2019; CCC: COVID-related high-risk chronic condition.
Number of patients, n (%)	1,509 (39)	786 (20)	547 (14)	1,022 (26)
Hospital admission, n (%)	559 (37)	373 (47)	275 (50)	644 (63)	< 0.001
Intensive care unit admission, n (%)	63 (4.2)	69 (8.8)	67 (12.3)	165 (16.1)	< 0.001
Receiving mechanical ventilation, n (%)	42 (2.8)	43 (5.5)	45 (8.2)	108 (10.6)	< 0.001
All-cause in-hospital mortality, n (%)	32 (2.1)	29 (3.7)	29 (5.3)	87 (8.5)	< 0.001

Table 3. Association Between Clinical Outcome and Number of CCCs Among COVID-19 Patients

No CCC

One CCC

Two CCCs

≥ 3 CCCs

P value

COVID-19: coronavirus disease 2019; CCC: COVID-related high-risk chronic condition.

Number of patients, n (%)

1,509 (39)

786 (20)

547 (14)

1,022 (26)

Hospital admission, n (%)

559 (37)

373 (47)

275 (50)

644 (63)

< 0.001

Intensive care unit admission, n (%)

63 (4.2)

69 (8.8)

67 (12.3)

165 (16.1)

< 0.001

Receiving mechanical ventilation, n (%)

42 (2.8)

43 (5.5)

45 (8.2)

108 (10.6)

< 0.001

All-cause in-hospital mortality, n (%)

32 (2.1)

29 (3.7)

29 (5.3)

87 (8.5)

< 0.001

**Table 4.** The Adjusted Odds Ratios (aOR) of Number of CCCs, Age, Gender, and Racial/Ethnical Predictive of Four Different Clinical Outcomes
Adjusted variables	Hospital admission, aOR (95% CI), P value	ICU admission, aOR (95% CI), P value	IMV, aOR (95% CI), P value	In-hospital mortality, aOR (95% CI), P value
CI: confidence interval; CCC: COVID-related high risk chronic condition; NHW: non-Hispanic White; NHB: non-Hispanic Black; ICU: intensive care unit; IMV: invasive mechanical ventilations. ^aOthers refer to American Indian, Alaska Native, Asian, Native Hawaiian or other Pacific Islanders, unknown, or patient refusal.
Number of CCCs
No	Reference	Reference	Reference	Reference
One	1.51 (1.26 - 1.81), P< 0.001	2.24 (1.57 - 3.21), P < 0.001	2.04 (1.31 - 3.17), P = 0.002	1.53 (0.91 - 2.58), P = 0.108
Two	1.60 (1.30 - 1.97), P < 0.001	3.11 (2.14 - 4.51), P < 0.001	3.02 (1.93 - 4.73), P < 0.001	1.94 (1.14 - 3.31), P = 0.014
≥ 3	2.56 (2.13 - 3.07), P < 0.001	4.22 (3.04 - 5.84), P < 0.001	3.95 (2.66 - 5.85), P < 0.001	2.84 (1.81 - 4.45), P < 0.001
Age
18 - 54 years	Reference	Reference	Reference	Reference
55 - 60 years	1.21 (1.00 - 1.46), P = 0.053	1.10 (0.80 - 1.52), P = 0.561	1.18 (0.81 - 1.74), P = 0 .392	1.88 (1.18 - 3.01), P = 0.008
61 - 65 years	1.31 (1.06 - 1.62), P = 0.013	1.38 (0.99 - 1.92), P = 0.060	1.51 (1.02 - 2.24), P = 0.039	2.16 (1.32 - 3.52), P = 0.002
66+ years	1.93 (1.59 - 2.35), P < 0.001	1.35 (1.00 - 1.82), P = 0.048	1.31 (0.91 - 1.88), P = 0.148	3.58 (2.38 - 5.37), P < 0.001
Sex
Female	Reference	Reference	Reference	Reference
Male	1.77 (1.55 - 2.02), P < 0.001	1.86 (1.48 - 2.34), P < 0.001	1.72 (1.31 - 2.27), P < 0.001	1.75 (1.27 - 2.41), P = 0.001
Populations
NHW	Reference	Reference	Reference	Reference
NHB	0.84 (0.69 - 1.01), P = 0.067	1.00 (0.73 - 1.39), P = 0.979	0.92 (0.62 - 1.36), P = 0.660	0.90 (0.58 - 1.39), P = 0.636
Hispanic	1.04 (0.87 - 1.24), P = 0.665	1.18 (0.87 - 1.59), P = 0.288	1.21 (0.84 - 1.73), P = 0.307	0.86 (0.57 - 1.31), P = 0.484
Others^a	0.97 (0.72 - 1.31), P = 0.860	1.60 (0.99 - 2.58), P = 0.054	1.62 (0.92 - 2.86), P = 0.095	1.59 (0.87 - 2.93), P = 0.132

Table 4. The Adjusted Odds Ratios (aOR) of Number of CCCs, Age, Gender, and Racial/Ethnical Predictive of Four Different Clinical Outcomes

Adjusted variables

Hospital admission, aOR (95% CI), P value

ICU admission, aOR (95% CI), P value

IMV, aOR (95% CI), P value

In-hospital mortality, aOR (95% CI), P value

CI: confidence interval; CCC: COVID-related high risk chronic condition; NHW: non-Hispanic White; NHB: non-Hispanic Black; ICU: intensive care unit; IMV: invasive mechanical ventilations. ^aOthers refer to American Indian, Alaska Native, Asian, Native Hawaiian or other Pacific Islanders, unknown, or patient refusal.

Number of CCCs

Reference

One

1.51 (1.26 - 1.81), P< 0.001

2.24 (1.57 - 3.21), P < 0.001

2.04 (1.31 - 3.17), P = 0.002

1.53 (0.91 - 2.58), P = 0.108

Two

1.60 (1.30 - 1.97), P < 0.001

3.11 (2.14 - 4.51), P < 0.001

3.02 (1.93 - 4.73), P < 0.001

1.94 (1.14 - 3.31), P = 0.014

≥ 3

2.56 (2.13 - 3.07), P < 0.001

4.22 (3.04 - 5.84), P < 0.001

3.95 (2.66 - 5.85), P < 0.001

2.84 (1.81 - 4.45), P < 0.001

Age

18 - 54 years

Reference

55 - 60 years

1.21 (1.00 - 1.46), P = 0.053

1.10 (0.80 - 1.52), P = 0.561

1.18 (0.81 - 1.74), P = 0 .392

1.88 (1.18 - 3.01), P = 0.008

61 - 65 years

1.31 (1.06 - 1.62), P = 0.013

1.38 (0.99 - 1.92), P = 0.060

1.51 (1.02 - 2.24), P = 0.039

2.16 (1.32 - 3.52), P = 0.002

66+ years

1.93 (1.59 - 2.35), P < 0.001

1.35 (1.00 - 1.82), P = 0.048

1.31 (0.91 - 1.88), P = 0.148

3.58 (2.38 - 5.37), P < 0.001

Sex

Female

Reference

Male

1.77 (1.55 - 2.02), P < 0.001

1.86 (1.48 - 2.34), P < 0.001

1.72 (1.31 - 2.27), P < 0.001

1.75 (1.27 - 2.41), P = 0.001

Populations

NHW

Reference

NHB

0.84 (0.69 - 1.01), P = 0.067

1.00 (0.73 - 1.39), P = 0.979

0.92 (0.62 - 1.36), P = 0.660

0.90 (0.58 - 1.39), P = 0.636

Hispanic

1.04 (0.87 - 1.24), P = 0.665

1.18 (0.87 - 1.59), P = 0.288

1.21 (0.84 - 1.73), P = 0.307

0.86 (0.57 - 1.31), P = 0.484

Others^a

0.97 (0.72 - 1.31), P = 0.860

1.60 (0.99 - 2.58), P = 0.054

1.62 (0.92 - 2.86), P = 0.095

1.59 (0.87 - 2.93), P = 0.132

**Table 5.** Using C-Statistics to Compare the Performance Accuracy of CCC, CCI, and ECI Predictive of Four Different Clinical Outcomes
	CCC	CCI	ECI	P value
CCC: COVID-related high-risk chronic condition; CCI: Charlson Comorbidity Index; ECI: Elixhauser Comorbidity Index.
Hospital admissions	0.66 (0.64 - 0.68)	0.66 (0.64 - 0.68)	0.66 (0.64 - 0.68)	0.9366
Intensive care unit admissions	0.69 (0.66 - 0.71)	0.68 (0.66 - 0.71)	0.67 (0.64 - 0.70)	0.0543
Receiving mechanical ventilations	0.69 (0.65 - 0.72)	0.68 (0.65 - 0.71)	0.67 (0.63 - 0.70)	0.0447
In-hospital mortality	0.73 (0.69 - 0.76)	0.72 (0.68 - 0.76)	0.71 (0.68 - 0.75)	0.0513

Table 5. Using C-Statistics to Compare the Performance Accuracy of CCC, CCI, and ECI Predictive of Four Different Clinical Outcomes

CCC

CCI

ECI

P value

CCC: COVID-related high-risk chronic condition; CCI: Charlson Comorbidity Index; ECI: Elixhauser Comorbidity Index.

Hospital admissions

0.66 (0.64 - 0.68)

0.9366

Intensive care unit admissions

0.69 (0.66 - 0.71)

0.68 (0.66 - 0.71)

0.67 (0.64 - 0.70)

0.0543

Receiving mechanical ventilations

0.69 (0.65 - 0.72)

0.68 (0.65 - 0.71)

0.67 (0.63 - 0.70)

0.0447

In-hospital mortality

0.73 (0.69 - 0.76)

0.72 (0.68 - 0.76)

0.71 (0.68 - 0.75)

0.0513