Patient and ward related risk factors in a multi-ward nosocomial outbreak of COVID-19: Outbreak investigation and matched case–control study

Leal, Jenine; O’Grady, Heidi M.; Armstrong, Logan; Dixit, Devika; Khawaja, Zoha; Snedeker, Kate; Ellison, Jennifer; Erebor, Joyce; Jamieson, Peter; Weiss, Amanda; Salcedo, Daniel; Roberts, Kimberley; Wiens, Karen; Croxen, Matthew A.; Berenger, Byron M.; Pabbaraju, Kanti; Lin, Yi-Chan; Evans, David; Conly, John M.

doi:10.1186/s13756-023-01215-1

Antimicrobial Resistance & Infection Control

Table 2 Patient characteristics prior to index date^a during COVID-19 outbreak

From: Patient and ward related risk factors in a multi-ward nosocomial outbreak of COVID-19: Outbreak investigation and matched case–control study

Variables	Nosocomial COVID-19 N = 39 (%)^b	Matched control N = 70 (%)^b	IRR (95%CI)	P value
Age, years, median (IQR)	76 (15.5)	73 (13)	1.04 (1.00–1.07)	0.024
Sex
Male	23 (59.0%)	49 (70.0%)	0.62 (0.36–1.04)	0.070
Underlying disease^c
Other Neurological Disorders	4 (10.3%)	2 (2.9%)	2.04 (1.12–3.74)	0.020
Fluid/Electrolyte Disorders	14 (35.9%)	10 (14.3%)	3.16 (1.57–6.37)	0.001
Elixhauser score (AHRQ)
Median (IQR)	6 (19.5)	7 (14)	1.03 (-1.05)	0.039
Mean (± SD)	9.87 (11.72)	8.38 (9.44)	1.03 (-1.05)	0.039
Laboratory findings^d
Abnormal WBC count	5 (12.8%)	13 (18.6%)	0.63 (0.31–1.30)	0.212
Abnormal Lymphocyte	18 (46.1%)	20 (28.6%)	1.82 (1.12–2.94)	0.016
Abnormal Creatinine	18 (46.1%)	24 (34.3%)	1.49 (0.94–2.35)	0.087
Abnormal Platelet	5 (12.8%)	7 (10.0%)	1.00 (0.57–1.78)	0.992
Abnormal Hemoglobin	18 (46.1%)	34 (48.6%)	0.86 (0.56–1.32)	0.492
Abnormal Neutrophil	9 (23.1%)	15 (21.4%)	1.01 (0.58–1.74)	0.984
Mobility-slightly limited or no limitations	34 (87.2%)	61 (87.1%)	1.14 (0.54–2.44)	0.726
Activity-walks occasionally or frequently	27 (69.2%)	60 (85.7%)	0.38 (0.23–0.62)	0.0001
Braden score, median (IQR)	20 (18–21)	20 (19–21)	0.97 (0.90–1.05)	0.482
Medications
Days on ACE inhibitors, mean (SD)	0.82 (1.98)	0.82 (1.85)	0.99 (0.85–1.16)	0.920
Days on angiotensin II inhibitors, mean (SD)	1.05 (2.22)	0.99 (2.20)	1.03 (0.93–1.13)	0.604
Days on angiotensin receptor blockers and neprilysin inhibitors, mean (SD)	0.11 (0.71)	0.06 (0.33)	1.29 (0.78–2.14)	0.321
Days on diuretic, mean (SD)	3.03 (3.16)	2.41 (2.83)	1.09 (1.01–1.18)	0.031
Days on immunosuppressive agents, mean (SD)	0.52 (1.84)	0.05 (0.51)	1.33 (1.10–1.60)	0.003

ACE angiotensin-converting enzyme, AHRQ Agency for Healthcare Research and Quality, CI confidence interval, IQR interquartile range, IRR incidence rate ratio, SD standard deviation
^aIndex date for cases was either the symptom onset date or first laboratory confirmation for SARS-CoV-2, whichever came first. Index date for controls was when the outbreak was declared, either 19 September 2020 or 30 September 2020
^bNumber and percentages displayed, unless otherwise indicated for continuous variables
^cOnly those comorbidities that were significantly different between cases and controls are displayed. Additional file 3 lists results for all comorbidities
^dAbnormal values based on laboratory measure values falling outside normal ranges as defined by laboratory and clinical criteria

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ISSN: 2047-2994

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