Readmission rates and outcomes in adults with and without COVID-19 following inpatient chemotherapy admission: A nationwide analysis

Table 1 Comparison of patients’ demographics between inpatient chemotherapy and readmission for inpatient chemotherapy, Nationwide Readmission Database, 2020

Variables (unit)	Index admission	30 d readmission	P value
Mean age ± SD (yr)	54.7 ± 17.71	53.53 ± 17.94
Age range categories (%)			< 0.001
18-44 yr	26.86	29.5
45-64 yr	40.06	39.62
65 yr and above	33.08	30.89
Sex (%)			0.182
Male	58.07	58.47
Female	41.93	41.53
Payer type (%)			< 0.001
Medicare	34.43	32.33
Medicaid	17.06	18.14
Private insurance	46.14	47.25
Self pay	2.36	2.28
Median household income (%)			0.617
0-25th quintile	22.28	21.96
26th-50th quintile	27.91	28.02
50th-75th quintile	25.61	25.85
> 75th quintile	24.19	24.18
ECI score (%)			< 0.001
0	4.88	4.14
1	18.61	17.7
2	23.75	23.35
3	20.61	20.53
≥ 4	32.15	34.28

ECI: Elixhauser comorbidity index.

Table 2 Comparing the 31 elixhauser comorbidities between index admission and 30-days readmission for inpatient chemotherapy, Nationwide Readmission Database, 2020

Variables (%)	Index	Readmission	P value
Congestive heart failure	5.45	5.83	0.02
Cardiac arrhythmias	12.14	13.13	< 0.001
Valvular diseases	2.48	2.12	0.001
Pulmonary circulation disorders	2.1	2.47	0.001
Peripheral vascular disorders	4.81	5.1	0.141
Hypertension, uncomplicated	34.12	32.88	0.001
Paralysis	1.06	1.17	0.181
Other neurologic disorders	4.72	5.72	< 0.001
Chronic pulmonary disease	11.07	10.5	0.012
Diabetics, uncomplicated	8.44	8.5	0.757
Diabetics, complicated	8.63	8.28	0.105
Hypothyroidism	9.88	9.61	0.134
Renal failure	7.75	6.89	< 0.001
Liver disease	4.06	4.09	0.854
Peptic ulcer disease	0.34	0.33	0.859
HIV/AIDS	1.26	1.44	0.003
Lymphoma	45.89	48.77	< 0.001
Metastatic cancer	14.93	14.78	0.637
Solid tumor without metastasis	24.4	24.84	0.255
RA/collagen vascular disease	2.03	1.9	0.226
Coagulopathy	12.64	14.41	< 0.001
Obesity	10.33	9.81	0.159
Weight loss	10.76	11.12	0.207
Fluid and electrolyte disorders	23.17	28.16	< 0.001
Blood loss anemia	0.39	0.35	0.497
Deficiency anemia	3.09	2.63	0.001
Alcohol abuse	1.13	0.98	0.103
Drug abuse	2.32	2.35	0.832
Psychosis	0.68	0.76	0.089
Depression	12.39	12.59	0.429
Hypertension, complicated	8.04	7.66	0.063

HIV/AIDS: Human immunodeficiency virus/acquired immuno-deficiency syndrome; RA: Rheumatoid arthritis.

Table 3 Comparison of the 31 elixhauser comorbidities between index admission and 90-days readmission for inpatient chemotherapy, Nationwide Readmission Database, 2020

Variables (%)	Index	Readmission	P value
Congestive heart failure	5.88	6.59	0.002
Cardiac arrhythmias	13.16	14.17	0.001
Valvular diseases	2.69	2.19	0.001
Pulmonary circulation disorders	2.28	2.57	0.052
Peripheral vascular disorders	4.72	5.19	0.024
Hypertension, uncomplicated	34.58	33.12	< 0.001
Paralysis	1.09	1.13	0.645
Other neurologic disorders	4.81	5.91	< 0.001
Chronic pulmonary disease	11.68	11.09	0.026
Diabetics, uncomplicated	8.54	8.51	0.908
Diabetics, complicated	8.86	8.7	0.539
Hypothyroidism	10.31	9.77	0.003
Renal failure	8.38	7.88	0.033
Liver disease	4.36	4.42	0.814
Peptic ulcer disease	0.29	0.37	0.196
HIV/AIDS	1.09	1.12	0.667
Lymphoma	43.95	44.89	0.012
Metastatic cancer	15.5	14.48	< 0.001
Solid tumor without metastasis	24.39	23.94	0.181
RA/collagen vascular disease	2.13	1.91	0.077
Coagulopathy	13.27	15.73	< 0.001
Obesity	10.41	9.77	0.166
Weight loss	11.8	12.44	0.055
Fluid and electrolyte disorders	24.87	30.26	< 0.001
Blood loss anemia	0.44	0.42	0.876
Deficiency anemia	3.16	2.51	< 0.001
Alcohol abuse	1.29	1.13	0.144
Drug abuse	2.33	2.31	0.922
Psychosis	0.71	0.77	0.269
Depression	12.23	12.95	0.015
Hypertension, complicated	8.81	8.75	0.785

HIV/AIDS: Human immunodeficiency virus/acquired immuno-deficiency syndrome; RA: Rheumatoid arthritis.

Table 4 Comparison of hospital specific characteristics of index admissions and readmissions for inpatient chemotherapy, Nationwide Readmission Database, 2020

Variables	Index	Readmission	P value
Hospital bed size (%)			0.002
Small	7.51	8.49
Medium	15.96	16.01
Large	76.53	75.5
Teaching status of hospital (%)			0.002
Metropolitan, non teaching	5.51	6.09
Metropolitan teaching	93.48	92.27
Non-metropolitan	1.01	1.64

Table 5 Independent predictors of 30 d readmission for inpatient chemotherapy, Nationwide Readmission Database, 2020

Variables	Hazard ratio	Confidence interval	P value
Age category
45-64 years	0.83	0.79-0.87	< 0.001
65 years and above	0.78	0.72-0.85	< 0.001
Discharge AMA	0.69	0.49-0.97	0.031
Payer type
Medicaid	1.04	0.97-1.12	0.299
Private insurance	1.02	0.99-1.09	0.564
Self pay	1.05	0.90-1.23	0.522
Median household income
25th-50th quantile	1.04	0.97-1.12	0.137
50th-75th quantile	1.04	0.96-1.09	0.103
> 75th quantile	1.03	0.90-1.09	0.263
COVID-19	0.91	0.68-1.22	0.543
Comorbidities
Congestive heart failure	0.92	0.85-1.00	0.059
Cardiac arrhythmias	0.96	0.91-1.01	0.147
Peripheral vascular disorders	1.09	1.00-1.19	0.048
Hypertension, uncomplicated	1.03	0.99-1.07	0.111
Paralysis	1.26	1.08-1.47	0.003
Chronic pulmonary disease	0.96	0.91-1.02	0.233
Diabetics, uncomplicated	0.94	0.89-1.00	0.058
Renal failure	0.89	0.82-0.96	0.004
Liver disease	0.9	0.82-0.98	0.023
HIV/AIDS	1.14	1.01-1.30	0.038
Lymphoma	1.23	1.17-1.28	< 0.001
Coagulopathy	0.91	0.86-0.97	0.002
Weight loss	0.97	0.92-1.04	0.457
Hypertension, complicated	1.05	0.96-1.15	0.28

AMA: Against medical advice; HIV/AIDS: Human immunodeficiency virus/acquired immuno-deficiency syndrome.

Table 6 Independent predictors of 90 d readmission for inpatient chemotherapy, Nationwide Readmission Database, 2020

Variables	Hazard ratio	Confidence interval	P value
Age category
45-64 yr	0.84	0.80-0.89	< 0.001
65 yr and above	0.74	0.68-0.80	< 0.001
Discharge AMA	0.65	0.47-0.90	0.01
Payer type
Medicaid	1.02	0.95-1.09	0.633
Private insurance	1.02	0.95-1.08	0.631
Self pay	1.15	0.99-1.33	0.056
Median household income
25th-50th quintile	1.03	0.97-1.09	0.329
50th-75th quintile	1.04	0.98-1.11	0.166
> 75th quintile	1.03	0.96-1.10	0.471
COVID-19	0.88	0.66-1.18	0.396
Comorbidities
Congestive heart failure	0.93	0.85-1.01	0.086
Cardiac arrhythmias	0.97	0.92-1.02	0.198
Peripheral vascular disorders	1.15	1.04-1.26	0.004
Hypertension, uncomplicated	1.02	0.98-1.07	0.296
Paralysis	1.21	1.02-1.43	0.027
Chronic pulmonary disease	0.97	0.92-1.03	0.386
Diabetics, uncomplicated	0.92	0.87-0.99	0.01
Renal failure	0.91	0.83-0.99	0.046
Liver disease	0.89	0.82-0.98	0.017
HIV/AIDS	1.1	0.94-1.29	0.211
Lymphoma	1.14	1.09-1.20	< 0.001
Coagulopathy	0.95	0.90-1.00	0.093
Weight loss	0.93	0.88-0.99	0.019
Hypertension, complicated	1.03	0.93-1.14	0.604

AMA: Against medical advice; HIV/AIDS: Human immunodeficiency virus/acquired immuno-deficiency syndrome.