Outcomes of hospital-acquired SARS-CoV-2 infection in the Canadian first wave epicentre: a retrospective cohort study

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Figure 1:
Flow chart of included patients with SARS-CoV-2 infection in hospital.
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Figure 2:
Epidemic curve of patients with SARS-CoV-2 infection in hospital. Note: HA = hospital-acquired, HCW = health care worker, NHA = non-hospital-acquired, PCR = polymerase chain reaction.

Table 1:

Baseline characteristics of patients with hospital-acquired and non-hospital-acquired SARS-CoV-2 infection

Characteristic	No. (%)^* of hospital-acquired cases n = 253 (36.3%)	No. (%)^* of non-hospital-acquired cases n = 444 (63.7%)	p value
Age, yr, median (IQR)	79 (68–86)	73 (58.5–85)
Age, yr			0.003
< 75	98 (38.7)	231 (52.0)
75–84	71 (28.1)	100 (22.5)
≥ 85	84 (33.2)	113 (25.5)
Female sex	128 (50.6)	228 (51.4)	0.85
Comorbidity^†
Moderate to severe chronic kidney disease^‡	35 (13.8)	52 (11.7)	0.42
Solid tumour			< 0.001
Localized	49 (19.4)	39 (8.8)
Metastatic	28 (11.1)	14 (3.2)
Hematologic malignancy	12 (4.7)	10 (2.3)	0.07
Diabetes	87 (34.4)	156 (35.1)	0.84
COPD	60 (23.7)	65 (14.6)	0.003
Myocardial infarction	18 (7.1)	33 (7.4)	0.91
Dementia	58 (22.9)	101 (22.8)	0.96
Charlson Comorbidity Index, median (IQR)	2 (1–4)	1 (0–3)
Provenance before admission^§			< 0.001
Home	180 (71.2)	237 (53.4)
Long-term care facility	9 (3.6)	49 (11.0)
Others	62 (24.4)	160 (36.1)
Reason for admission			< 0.001
Infectious	70 (27.9)	7 (1.6)
Nervous system	38 (15.1)	7 (1.6)
Neoplasm	37 (14.7)	4 (0.9)
Gastrointestinal	21 (8.4)	9 (2.0)
Other	85 (33.9)	419 (93.9)
Deprivation index of 4 or 5^¶	150 (59.3)	243 (54.7)	0.16
Timing of diagnosis, d			< 0.001
0–6	62 (24.5)	444 (100)
7–14	91 (36.0)	0 (0)
> 14	100 (39.5)	0 (0)
Treatment with corticosteroids	46 (18.2)	66 (14.9)	0.25
Surgical procedure	37 (14.6)	13 (2.9)	0.001
ICU admission	21 (8.3)	85 (19.1)	< 0.001
ICU admission within 7 days	17 (81.0)	74 (87.1)	0.47
Mechanical ventilation	9 (3.6)	58 (13.0)	0.001

Note: COPD = chronic obstructive pulmonary disease, ICU = intensive care unit, IQR = interquartile range, RPA = Résidence privée pour ainés (private residences for older adults).
↵* Unless stated otherwise.
↵† Selected comorbidities from the Charlson Comorbidity Index.12
↵‡ Moderate to severe chronic renal disease, defined as creatinine > 265 μmol/L, as defined in the Charlson Comorbidity Index.12
↵§ Others: congregate living settings such as RPA, intermediate and family-type resources (IR-FTR), transfer from another hospital and rehabilitation.
↵¶ The deprivation index is based on patient postal code and 2016 census data. Results of various indicators are aggregated to create a deprivation index to identify a deprived population. A score from 1 (least deprived) to 5 (most deprived) is calculated, with 4 and 5 signifying being deprived and most deprived.11

Table 2:

Outcomes in patient with hospital-acquired and non-hospital-acquired SARS-CoV-2 infection

Outcomes	No. (%)^* of hospital-acquired cases n = 253 (36.3%)	No. (%)^* of non-hospital-acquired cases n = 444 (63.7%)	p value
Mortality by age, yr	99 (39.1)	115 (25.9)	0.001
< 75	29 (29.6)	23 (10.0)
75–84	33 (46.5)	37 (37.0)
≥ 85	37 (44.1)	55 (48.7)
Hospital length of stay, median (IQR)	25.0 (15–46)	8 (3.5–16)
Disposition at discharge^†			0.001
Home	74 (48.1)	197 (59.9)
Long-term care facility	32 (20.8)	73 (22.2)
Rehabilitation	26 (16.9)	20 (6.1)
Others^‡	22 (14.3)	39 (11.9)
Readmission within 90 days after discharge	24 (15.3)	13 (4.0)	0.001

Note: IQR = interquartile range, RPA = Résidence privée pour ainés (private residences for older adults).
↵* Unless stated otherwise.
↵† Disposition at discharge was calculated only for survivors (n = 154 in hospital-acquired group and n = 329 in non-hospital-acquired group).
↵‡ Others: congregate living settings such as RPA, intermediate and family-type resources (IR-FTR) and transfer to another hospital or dedicated centres for quarantine of patients with COVID-19.

Table 3:

Multivariable logistic regression of factors associated with mortality related to SARS-CoV-2 infection

Factors	OR (95% CI)
HA cases, age, yr^*
< 75	2.78 (1.44–5.38)
75–84	1.25 (0.64–2.42)
≥ 85	0.75 (0.41–1.35)
Sex
Female	0.60 (0.42–0.87)
Solid tumour^†
Localized	1.07 (0.63–1.80)
Metastatic	5.91 (2.84–12.30)
Hematologic malignancy	6.66 (2.41–18.4)
Moderate to severe chronic renal disease^‡	2.96 (1.74–5.04)
Diabetes	1.20 (0.81–1.76)
Chronic obstructive pulmonary disease	1.02 (0.64–1.62)
Myocardial infarction	0.90 (0.47–1.74)

Note: CI = confidence interval, HA = hospital-acquired, OR = odds ratio, Ref. = reference.
↵* Ref. = non-HA cases.
↵† Ref. = y.
↵‡ Defined as creatinine > 265 μmol/L.