Predictors of Length of Hospital Stay, Mortality, and Outcomes Among Hospitalised COVID-19 Patients in Saudi Arabia: A Cross-Sectional Study

Figures & data

Table 1 Patients Demographic Characteristics at Presentation

Demographics	All Patients (n=706)	Mild Cases (n= 238)	Moderate Cases (n= 214)	Severe Cases (n= 171)	Critical Cases (n= 83)	P-value
Age (years; mean (SD))	48.0 years (15.6)	41.4 years (14.1)	48.4 years (14.3)	51.5 years (16.0)	58.4 years (14.5)	0.001**
Gender (Total n= 426, Mild n= 168, Moderate n= 154, Severe n= 58, Critical n= 46)
Male No. (%)	292 (68.5)	116 (69.0)	96 (62.3)	49 (84.5)	31 (67.4)	0.022*
Healthcare worker (Total n= 705, Mild n= 238, Moderate n= 214, Severe n= 170, Critical n= 83)
Yes No. (%)	25 (3.5)	11 (4.6)	6 (2.8)	6 (3.5)	2 (2.4)	0.691
Nationality No. (%)
Non-Saudi	435 (61.6)	160 (67.2)	135 (63.1)	90 (52.6)	50 (60.2)	0.026*
Smoking history (Total n= 698, Mild n= 234, Moderate n= 212, Severe n= 169, Critical n= 83)
Yes No. (%)	122 (17.3)	46 (19.7)	31 (14.6)	36 (21.3)	9 (10.8)	0.102
Body mass index (BMI)
BMI >30 kg/m^2	88 (15.8)	18 (11.1)	27 (16.7)	30 (18.9)	13 (17.8)	0.250
Comorbidities No. (%)
Diabetes mellitus	254 (36.0)	55 (23.1)	72 (33.6)	73 (42.7)	54 (65.1)	0.000***
Hypertension	213 (30.2)	38 (16.0)	68 (31.8)	62 (36.3)	45 (54.2)	0.000***
Coronary artery disease	77 (10.9)	4 (1.7)	19 (8.9)	35 (20.5)	19 (22.9)	0.000***
End-Stage Renal Disease	64 (9.1)	8 (3.4)	20 (9.4)	13 (7.6)	23 (27.7)	0.000***
Asthma	28 (4.0)	11 (4.6)	7 (3.3)	8 (4.7)	2 (2.4)	0.730
Congestive heart failure	27 (3.8)	1 (0.4)	5 (2.3)	13 (7.6)	8 (9.6)	0.000***
Cerebrovascular accident	17 (2.4)	1 (0.4)	0	7 (4.1)	9 (10.8)	0.000***
Chronic obstructive pulmonary disease	14 (2.0)	2 (0.8)	4 (1.9)	5 (2.9)	3 (3.6)	0.320
Chronic liver disease	4 (0.6)	0	1 (0.5)	1 (0.6)	2 (2.4)	0.095
Cancer	3 (0.4)	0	1 (0.5)	0	2 (2.4)	0.024*
Tracing history No. (%)
Recent travel history (Total n= 704, Mild n= 238, Moderate n= 212, Severe n= 171, Critical n= 83) (Yes) No. (%)	69 (9.8)	30 (12.6)	32 (15.1)	6 (3.5)	1 (1.2)	0.000***
Contact with traveller (Total n= 706, Mild n= 238, Moderate n= 214, Severe n= 171, Critical n= 83) (Yes) No. (%)	84 (11.9)	38 (16.0)	39 (18.2)	5 (2.9)	2 (2.4)	0.000***
Contact with COVID-19 patient (Total n= 706, Mild n= 238, Moderate n= 214, Severe n= 171, Critical n= 83) (Yes) No. (%)	324 (45.9)	127 (53.4)	101 (47.2)	65 (38.0)	31 (37.3)	0.007**
Vital signs upon arrival to hospital No. (%)
Fever (≥ 38°C) (Yes) No. (%)	334 (47.3)	71 (29.8)	84 (39.3)	127 (74.3)	52 (62.7)	0.000***
Respiratory rate > 30 (Yes) No. (%)	67 (9.5)	1 (0.4)	1 (0.5)	38 (22.2)	27 (32.5)	0.000***
SPO2<93 (Yes) No. (%)	156 (22.1)	6 (2.5)	6 (2.8)	97 (56.7)	47 (56.6)	0.000***
Heart rate>125 (Yes) No. (%)	30 (4.2)	0	4 (1.9)	8 (4.7)	18 (21.7)	0.000***
Outcome No. (%) (n= 680)
Deceased	54 (7.6)	0	0	1 (0.6)	53 (71.6)	0.000***
Not recovered	3 (0.4)	0	0	0	3 (4.1)	0.000***
Recovered	623 (91.6)	235 (100)	214 (100)	156 (99.4)	18 (24.3)	0.000***
Respiratory diseases
Venous thromboembolism	21 (3.0)	0	3 (1.4)	4 (2.3)	14 (16.9)	0.000***
Pneumonia (radiologically)	450 (63.6)	0	215 (99.5)	155 (90.6)	80 (96.4)	0.000***

Notes: *p < 0.05; **p < 0.01; ***p < 0.001.

Abbreviations: COVID-19, coronavirus disease-2019; SD, standard deviation; No, number (frequency).

Table 2 Patient Signs and Symptoms Stratified by Severity

Variable	All Patients (n=706)	Mild Cases (n= 238)	Moderate Cases (n= 214)	Severe Cases (n= 171)	Critical Cases (n= 83)	P-value
Fever	511 (72.4)	143 (60.1)	152 (71.0)	150 (87.7)	66 (79.5)	0.000***
Cough	445 (63.0)	140 (58.8)	128 (59.8)	117 (68.4)	60 (72.3)	0.047*
Shortness of breath	398 (56.4)	90 (37.8)	97 (45.3)	143 (83.6)	68 (81.9)	0.000***
Fatigue	176 (25.0)	52 (21.8)	43 (20.1)	61 (35.9)	20 (24.1)	0.002**
Nausea/vomiting	118 (16.7)	38 (16.0)	23 (10.7)	43 (25.1)	14 (16.9)	0.003**
Sore throat	115 (16.3)	54 (22.7)	29 (13.6)	25 (14.6)	7 (8.5)	0.006**
Myalgia	108 (15.3)	31 (13.0)	24 (11.3)	42 (24.6)	11 (13.3)	0.002**
Headache	102 (14.4)	31 (13.0)	28 (13.1)	31 (18.1)	12 (14.5)	0.460
Loss of taste	98 (13.9)	30 (12.6)	21 (9.8)	21 (12.3)	26 (31.3)	0.000***
Loss of smell	90 (12.7)	28 (11.8)	19 (8.9)	18 (10.5)	25 (30.1)	0.000***
Diarrhea	52 (7.4)	19 (8.0)	13 (6.1)	15 (8.8)	5 (6.0)	0.705
Sputum	35 (5.0)	10 (4.2)	8 (3.7)	11 (6.4)	6 (7.2)	0.447
Runny nose	25 (3.5)	16 (6.7)	5 (2.3)	2 (1.2)	2 (2.4)	0.012*
Haemoptysis	2 (0.3)	0	0	1 (0.6)	1 (1.2)	0.228

Notes: *p<0.05; **p<0.01; ***p<0.000.

Table 3 Laboratory Findings of the Study Participants Stratified by Severity

Variable	All Patients (n=706)	Mild Cases (n= 238)	Moderate Cases (n= 214)	Severe Cases (n= 171)	Critical Cases (n= 83)	P-value
Complete Blood Count
WBC >10,000 (Total n= 701, Mild n= 234, Moderate n= 214, Severe n= 171, Critical n= 82) (Yes) No. (%)	116 (16.5)	17 (7.3)	22 (10.3)	32 (18.7)	45 (54.9)	0.000***
WBC <4000 (Total n= 705, Mild n= 238, Moderate n= 214, Severe n= 171, Critical n= 82) (Yes) No. (%)	98 (13.9)	34 (14.3)	34 (15.9)	21 (12.3)	9 (11.0)	0.638
Lymphocyte count <1500 (Total n= 704, Mild n= 237, Moderate n= 214, Severe n= 171, Critical n= 82) (Yes) No. (%)	148 (21.0)	25 (10.5)	40 (18.7)	43 (25.1)	40 (48.8)	0.000***
NLR (Mean (SD))	9.9 (33.5)	1.17 (2.33)	1.23 (2.28)	9.2 (66.9)	12.8 (18.8)	0.000***
Platelet < 150 (Total n= 704, Mild n= 238, Moderate n= 214, Severe n= 170, Critical n= 82) (Yes) No. (%)	89 (12.6)	21 (8.8)	23 (10.7)	22 (12.9)	23 (28.0)	0.000***
D.dimer >0.5 (Total n= 703, Mild n= 236, Moderate n= 214, Severe n= 171, Critical n= 82) (Yes) No. (%)	210 (29.9)	27 (11.4)	35 (16.4)	91 (53.2)	57 (69.5)	0.000***
Blood Groups (Total n= 322, Mild n= 82, Moderate n= 86, Severe n= 114, Critical n= 40) (Yes) No. (%)
A+	115 (35.7)	34 (41.5)	21 (24.4)	44 (38.6)	16 (40.0)	0.000***
A-	2 (0.6)	0	0	2 (1.8)	0
AB+	22 (6.8)	5 (6.1)	5 (5.8)	9 (7.9)	3 (7.5)
AB-	1 (0.3)	1 (1.2)	0	0	0
B+	66 (20.5)	16 (19.5)	24 (27.9)	20 (17.5)	6 (15.0)
B-	3 (0.9)	1 (1.2)	2 (2.3)	0	0
O+	92 (28.6)	19 (23.2)	27 (31.4)	32 (28.1)	14 (35.0)
O–	21 (6.5)	6 (7.3)	7 (8.1)	7 (6.1)	1 (2.5)
Inflammatory measures
ESR>10 mm/h (Total n= 704, Mild n= 238, Moderate n= 214, Severe n= 170, Critical n= 82) (Yes) No. (%)	366 (52.0)	67 (28.2)	99 (46.3)	139 (81.8)	61 (74.4)	0.000***
CRP>0.3 mg/dl (Total n= 704, Mild n= 238, Moderate n= 213, Severe n= 171, Critical n= 82) (Yes) No. (%)	340 (48.3)	65 (27.3)	97 (45.6)	132 (77.2)	46 (56.1)	0.000***
Ferritin>400mcg/L (Total n= 705, Mild n= 238, Moderate n= 214, Severe n= 171, Critical n= 82) (Yes) No. (%)	204 (28.9)	40 (16.8)	43 (20.1)	76 (44.4)	45 (54.9)	0.000***
Procalcitonin>0.5ug/L (Total n= 705, Mild n= 237, Moderate n= 216, Severe n= 170, Critical n= 82) (Yes) No. (%)	13 (1.8)	1 (0.4)	6 (2.8)	2 (1.2)	4 (4.9)	0.041*
Liver Function Tests (Total n= 705, Mild n= 238, Moderate n= 214, Severe n= 171, Critical n= 82) (Yes) No. (%)
AST>40	251 (35.6)	58 (24.4)	61 (28.5)	81 (47.4)	51 (62.2)	0.000***
ALT>40	237 (33.6)	55 (23.1)	56 (26.2)	81 (47.4)	45 (54.9)	0.000***
LDH>230 U/L (Total n= 704, Mild n= 238, Moderate n= 213, Severe n= 171, Critical n= 82) (Yes) No. (%)	282 (40.1)	51 (21.4)	62 (29.1)	108 (63.2)	61 (74.4)	0.000***
Bilirubin>18.7 umol/L	44 (6.2)	6 (2.5)	9 (4.2)	11 (6.4)	18 (22.0)	0.000***
Renal function tests (Total n= 705, Mild n= 238, Moderate n= 214, Severe n= 171, Critical n= 82) (Yes) No. (%)
Creatinine>115umol/L	121 (17.2)	13 (5.5)	28 (13.1)	34 (19.9)	46 (56.1)	0.000***
Urea>6.04 mmol/L (Total n= 704, Mild n= 237, Moderate n= 214, Severe n= 171, Critical n= 82) (Yes) No. (%)	171 (24.3)	19 (8.0)	46 (21.5)	57 (33.3)	49 (59.8)	0.000***

Notes: *p < 0.05; ***p < 0.001. Reference values; WBC: 4000–1000; lymphocyte: 1500–4000; NLR: 0.78–3.53; platelet: 150–400; D.dimer: 0–0.55; ESR: 0–10; CRP: 0–0.3; ferritin: 10–291; procalcitonin: 0–0.5; AST: 10–34; ALT: 46–120; LDH: 80–230; bilirubin: 0–18.7; creatinine: 44–90; urea: 3.2–8.2.

Abbreviations: AST, aspartate transaminase; ALT, alanine transaminase; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; NLR, neutrophil-lymphocyte ratio; LDH, lactate dehydrogenase; WBC, white blood cell.

Table 4 Logistic Regression to Identify Risk Factors of Death

Demographics	Odds Ratio for Death^a	95% CI	Odds Ratio for Death^b	95% CI
Age	1.06	(1.04 – 1.08)***	1.05	(1.02 – 1.09)**
Gender
Female (Reference category)	1.00		1.00
Male	0.77	(0.39 – 1.54)	0.30	(0.11 – 0.81)*
Smoking history
No (Reference category)	1.00		1.00
Yes	0.36	(0.13 – 1.02)	0.49	(0.13 – 1.91)
BMI
BMI <30 kg/m^2 (Reference category)	1.00		1.00
BMI >30 kg/m^2	1.24	(0.59 – 2.63)	0.25	(0.06 – 1.01)
Comorbidities (not having the disease is the reference category)
Diabetes mellitus	4.82	(2.63 – 8.85)***	1.64	(0.59 – 4.54)
Hypertension	5.91	(3.24 – 10.77)***	1.63	(0.55 – 4.85)
Coronary artery disease	3.04	(1.54 – 5.99)**	1.08	(0.28 – 4.17)
End-Stage Renal Disease	6.97	(3.69 – 13.17)***	6.44	(2.20 – 18.87)**
Asthma	0.42	(0.06 – 3.13)	0.80	(0.07 – 8.82)
Congestive heart failure	3.59	(1.38 – 9.32)**	0.85	(0.17 – 4.31)
Cerebrovascular accident	10.18	(3.63 – 28.54)***	2.09	(0.37 – 11.92)
Chronic obstructive pulmonary disease	0.89	(0.11 – 6.90)	–
Chronic liver disease	11.92	(1.65 – 86.38)*	–
Cancer	23.96	(2.14 – 268.68)*	–
Vital signs upon arrival to hospital (having the normal range is the reference category)
Fever (≥ 38°C) (Yes)	1.28	(0.73 – 2.24)	1.46	(0.68 – 3.13)
Respiratory rate > 30 (Yes)	7.09	(3.66 – 13.73)***	153.90	(9.80 – 2416.60)***
SPO2<93 (Yes)	2.63	(1.46 – 4.73)**	9.92	(4.19 – 23.50)***
Heart rate>125 (Yes)	12.87	(5.74 – 28.86)***	19.82	(5.22 – 75.25)***
Outcome
Venous thromboembolism (Yes)	17.54	(6.90 – 44.61)***	12.86	(3.07 – 53.92)***
Pneumonia Radiologically(Yes)	2.35	(1.19 – 4.61)*	1.37	(0.95 – 1.98)
Complete Blood Count (having the normal range is the reference category)
WBC >10,000 (Yes)	12.36	(6.74 – 22.68)***	16.47	(6.78 – 40.00)***
WBC <4000 (Yes)	0.34	(0.10 – 1.11)	0.31	(0.07 – 1.48)
Lymphocyte count <1500 (Yes)	5.70	(3.19 – 10.17)***	10.17	(4.29 – 24.14)***
NLR (Mean (SD))	1.00	(1.00 – 1.01)	1.23	(1.15 – 1.32)***
Platelet < 150 (Yes)	5.73	(3.12 – 10.53)***	9.92	(4.01 – 24.52)***
D.dimer >0.5 (Yes)	8.47	(4.48 – 16.01)***	13.31	(5.45 – 32.49)***
Inflammatory measures (having the normal range is the reference category)
ESR>10 mm/h (Yes)	2.89	(1.54 – 5.42)**	4.08	(1.72 – 9.68)**
CRP>0.3 mg/dl (Yes)	0.90	(0.52 – 1.55)	0.84	(0.39 – 1.80)
Ferritin>400mcg/L (Yes)	3.89	(2.19 – 6.91)***	18.55	(6.89 – 49.96)***
Procalcitonin>0.5ug/L (Yes)	5.58	(1.66 – 18.77)**	8.23	(1.81 – 37.40)**
Liver Function Tests (having the normal range is the reference category)
AST>40 (Yes)	3.71	(2.07 – 6.67)***	8.85	(3.64 – 21.50)***
ALT>40 (Yes)	2.41	(1.37 – 4.24)**	4.78	(2.11 – 10.83)***
LDH>230 U/L (Yes)	6.09	(3.13 – 11.82)***	21.26	(7.61 – 59.40)***
Bilirubin>18.7 umol/L (Yes)	1.51	(1.14 – 2.00)**	15.06	(4.63 – 48.99)***
Renal function tests (having the normal range is the reference category)
Creatinine>115umol/L (Yes)	18.00	(9.46 – 34.25)***	36.33	(13.65 – 96.66)***
Urea>6.04 mmol/L (Yes)	4.48	(2.54 – 7.90)***	15.27	(6.29 – 37.07)***
Blood Groups (blood group A is the reference category)
B	0.35	(0.08 – 1.47)	0.51	(0.11 – 2.36)
AB	–	–	1.08	(0.02 – 54.95)
O	1.52	(0.77 – 2.99)	1.50	(0.57 – 3.96)

Notes: *p < 0.05; **p < 0.01; ***p < 0.001. ^aBinary logistic regression. ^bMultiple logistic regression adjusted for the following variables (age, gender, and comorbidities). Reference values; WBC: 4000–1000; lymphocyte: 1500–4000; NLR: 0.78–3.53; platelet: 150–400; D.dimer: 0–0.55; ESR: 0–10; CRP: 0–0.3; ferritin: 10–291; procalcitonin: 0–0.5; AST: 10–34; ALT: 46–120; LDH: 80–230; bilirubin: 0–18.7; creatinine: 44–90; urea: 3.2–8.2.

Abbreviations: AST, aspartate transaminase; ALT, alanine transaminase; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; NLR, neutrophil-lymphocyte ratio; LDH, lactate dehydrogenase; WBC, white blood cell.

Table 5 Linear Regression to Identify Predictors of Length of Stay

Demographics	Model a			Model b
	B	SE	ß	B	SE	ß
Age	0.07	0.02	0.145***	−0.013	0.02	−0.03
Gender
Female	0.93	0.68	−0.07	−1.21	0.66	−0.09
Smoking history
Yes	3.04	0.71	−0.16***	−1.75	1.03	−0.11
BMI
BMI >30 kg/m^2	0.12	0.77	0.01	4.27	6.70	0.04
Comorbidities (not having the disease is the reference category)
Diabetes mellitus	2.46	0.56	0.17***	0.73	0.76	0.05
Hypertension	3.07	0.58	0.20***	0.55	0.82	0.04
Coronary artery disease	3.06	0.86	0.13***	−1.00	1.21	−0.04
End-Stage Renal Disease	7.68	0.91	0.31***	−1.04	2.00	−0.03
Asthma	1.20	1.40	0.03	−0.28	2.16	−0.01
Congestive heart faliure	3.77	1.40	0.10**	−1.04	2.00	−0.03
Cerebrovascular accident	5.31	1.74	0.12**	7.82	2.18	0.17***
Chronic obstructive pulmonary disease	3.93	1.92	0.08*	3.63	3.96	0.05
Chronic liver disease	3.08	3.59	0.03	2.76	4.83	0.03
Cancer	−0.60	4.14	−0.01	−4.88	3.98	−0.06
Vital signs upon arrival to hospital
Fever (≥ 38°C) (Yes)	2.19	0.54	0.15***	1.83	0.64	0.13**
Respiratory rate > 30 (Yes)	5.15	0.90	0.21***	0.83	2.38	0.02
SPO2<93 (Yes)	1.90	0.48	0.15***	0.21	0.97	0.01
Heart rate>125 (Yes)	4.95	1.32	0.14***	0.54	1.82	0.01
Outcome
Venous thromboembolism (Yes)	5.04	1.62	0.12**	2.19	2.06	0.05
Pneumonia (Yes)	2.79	0.42	0.24***	1.19	0.44	0.13**
Complete Blood Count
WBC >10,000 (Yes)	4.02	0.72	0.21***	2.37	0.87	0.13**
WBC <4000 (Yes)	−0.38	0.79	−0.02	1.69	0.93	0.09
Lymphocyte count <1500 (Yes)	1.02	0.67	0.06	1.13	0.89	0.06
NLR (Mean (SD))	0.00	0.01	0.02	0.07	0.06	0.06
Platelet < 150 (Yes)	0.24	0.81	0.01	0.45	1.07	0.02
D.dimer >0.5 (Yes)	3.57	0.58	0.23***	2.57	0.87	0.15**
Inflammatory measures
ESR>10 mm/h (Yes)	2.09	0.54	0.15***	1.64	0.64	0.12*
CRP>0.3 mg/dl (Yes)	2.10	0.54	0.15***	2.74	0.64	0.20***
Ferritin>400mcg/L (Yes)	4.59	0.57	0.29***	3.70	0.72	0.24***
Procalcitonin>0.5ug/L (Yes)	4.46	2.00	0.08*	4.94	1.78	0.13**
Liver Function Tests
AST>40	−0.27	0.57	−0.02	−0.81	0.69	−0.06
ALT>40	−0.12	0.57	−0.01	−0.82	0.71	−0.06
LDH>230 U/L (Yes)	2.09	0.55	0.14***	2.32	0.70	0.16**
Bilirubin>18.7 umol/L	0.61	0.43	0.05	1.03	1.48	0.04
Renal function tests
Creatinine>115umol/L	4.90	0.69	0.26***	2.44	1.09	0.13*
Urea>6.04 mmol/L (Yes)	2.89	0.54	0.20***	1.69	0.91	0.10
Blood Groups
B	−1.38	0.92	−0.06	−1.03	1.12	−0.04
AB	−3.58	3.22	−0.04	2.70	4.83	0.03
O	0.52	0.74	0.03	3.43	0.95	0.17***

Notes: *p < 0.05; **p < 0.01; ***p < 0.001. Model a: Univariate linear regression. Model b: Multiple linear regression adjusted for the following variables (age, gender and comorbidities).

Abbreviations: AST, aspartate transaminase; ALT, alanine transaminase; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; NLR, neutrophil-lymphocyte ratio; LDH, lactate dehydrogenase; WBC, white blood cell; B, the average change in the dependent variable associated with a 1 unit change in the independent variable, statistically controlling for the other independent variables; SE, it is the standard deviation of its sampling distribution or an estimate of that standard deviation; ß, a statistical measure that compares the strength of the effect of each individual independent variable to the dependent variable.