Abstract
Background
Objective
Methods
Results
Conclusion
Keywords
Introduction
WHO Covid 19 Briefing [Internet]. Available from: https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19-11-march-2020
Službena stranica Vlade za pravodobne i točne informacije o koronavirusu [Internet]. koronavirus.hr. [cited 2020 Apr 19]. Available from: https://www.koronavirus.hr/
ANZICS COVID-19 Guidelines [Internet]. ANZICS. [cited 2020 Jun 1]. Available from: https://www.anzics.com.au/coronavirus-guidelines/
Methods
Statistical analysis
Službena stranica Vlade za pravodobne i točne informacije o koronavirusu [Internet]. koronavirus.hr. [cited 2020 Apr 19]. Available from: https://www.koronavirus.hr/
The jamovi project. jamovi, www.jamovi.org [Internet]. 2019. Available from: www.jamovi.org
Kassambara A., Kosinski M., Biecek P. survminer: Drawing Survival Curves using “ggplot2”. [R package] [Internet]. 2019. Available from: https://CRAN.R-project.org/package=survminer.
Harrison E., Drake T., Ots R. finalfit: Quickly Create Elegant Regression Results Tables and Plots when Modelling. [R package] [Internet]. 2019. Available from: https://CRAN.R-project.org/package=finalfit
JASP [Internet]. JASP Team; 2020. Available from: https://jasp-stats.org
Results

Variable | Emergency department | External ICU | Ward | P |
---|---|---|---|---|
Age (years) | 71 (62–79) | 73 (64–79) | 72 (64–78) | 0.406 |
BMI (kg/m2) | 29.9 ± 5.2 | 29.6 ± 5.9 | 31.7 ± 6.1 | 0.088 |
Number of comorbidities | 3 (2–4) | 3 (2–4) | 3 (2–4) | 0.300 |
SARS-CoV-2 positive days | 1 (1–6)* | 5 (1–10) | 7 (4–10) | <0.001* |
CCI | 5 (3–7) | 5 (4–7) | 5 (3–6) | 0.356 |
SOFA | 4 (2–6) | 4 (2–6) | 4 (2–5) | 0.443 |
PaO2/FiO2 (mmHg) | 95 (63–180)* | 75 (60–129) | 68 (54–96) | <0.001* |
Ferritin (mg/L) | 1.34 ± 1.26 | 1.48 ± 1.28 | 1.37 ± 1.02 | 0.627 |
D-dimer (mg/L) | 3.6 (1.3–4.3) | 2.2(1.1–4.3) | 3.1 (1.4–4.3) | 0.266 |
CRP (mg/L) | 124 (72–183) | 132 (74–196) | 122 (78–175) | 0.945 |
PCT (ng/ml) | 0.58 (0.19–1.96) | 0.64 (0.26–3.39) | 0.46 (0.17–1.6) | 0.343 |
IL-6 (pg/ml) | 63 (27–147) | 69 (34–142) | 70 (30–179) | 0.873 |
Lactate (mmol/L) | 1.7 (1.3–2.1) | 1.6 (1.3–3.4) | 1.6 (1.2–2.6) | 0.277 |
GFR (ml/min/1.73 m2) | 69.5 ± 35.8 | 68.6 ± 37.0 | 76.2 ± 32.0 | 0.054 |
WBC (x109/L) | 12.6 ± 8.6 | 12.1 ± 5.9 | 12.6 ± 7.0 | 0.809 |
Neutrophil (%) | 85.1 ± 12.8 | 85.7 ± 89.2 | 87.0 ± 10.9 | 0.199 |
Lymphocyte (%) | 5.7 (3.3–9.2) | 4.7 (2.4–9.3) | 5.4 (3.4–8.6) | 0.432 |
Ventilatory support

Renal replacement therapy
Factors affecting survival
Variable | Survivors | Non-survivors | P |
---|---|---|---|
Age (years) | 65 (56–73) | 74 (67–79) | < 0.001 |
BMI (kg/m2) | 31.2 ± 6.2 | 30.1 ± 5.6 | 0.411 |
Number of comorbidities | 2 (1–4) | 3 (2–4) | 0.001 |
SARS-CoV-2 positive days | 5 (1–8) | 5 (2–9) | 0.067 |
CCI | 3 (2–5) | 5 (4–7) | < 0.001 |
SOFA | 2 (2–4) | 4 (2–6) | < 0.001 |
PaO2/FiO2 (mmHg) | 100 (70–224) | 69 (55–103) | < 0.001 |
Ferritin (mg/L) | 1.15 ± 0.98 | 1.48 ± 1.06 | 0.003 |
D-dimer (mg/L) | 2.54 ± 1.61 | 2.88 ± 3.35 | 0.013 |
CRP (mg/L) | 112 (46–171) | 129 (80–190) | 0.001 |
PCT (ng/ml) | 0.28 (0.10–0.82) | 0.69 (0.24–2.5) | < 0.001 |
IL-6 (pg/ml) | 31 (14–94) | 81 (43–187) | < 0.001 |
Lactate (mmol/L) | 1.4 (1.1–1.8) | 1.8 (1.3–3.4) | 0.016 |
GFR (ml/min/1.73 m2) | 91 (61–106) | 72 (41–92) | < 0.001 |
WBC (x109/L) | 10.4 (7.7–14) | 11.2 (8.2–16.4) | 0.030 |
Neutrophil (%) | 86.6 (80.3–90.9) | 89.7 (85.8–92.9) | < 0.001 |
Lymphocyte (%) | 6.5 (4.1–10.7) | 4.9 (2.9–8.3) | < 0.001 |
Age group < 45 | 12 (57.1%) | 9 (42.9%) | <0.001 |
Age group 45 - 65 | 78 (45.6%) | 93 (54.4%) | |
Age group 65 - 75 | 56 (24.8%) | 170 (75.2%) | |
Age group > 75 | 43 (15.7%) | 231 (84.3%) |
Factor | Survivors | Non-survivors | OR and 95% CI (univariable) | OR and 95% CI (multivariable) | |
---|---|---|---|---|---|
Ward admission | Y | 71 (17.9) | 325 (82.1) | – | – |
N | 118 (39.9) | 178 (60.1) | 0.33 (0.23–0.46, p<0.001) | 0.54 (0.26–1.13, p = 0.106) | |
Diabetes mellitus | Y | 46 (20.4) | 179 (79.6) | – | – |
N | 142 (30.5) | 323 (69.5) | 0.58 (0.40–0.85, p = 0.006) | 0.56 (0.24–1.28, p = 0.176) | |
Arterial hypertension | Y | 124 (25.2) | 368 (74.8) | – | – |
N | 64 (32.2) | 135 (67.8) | 0.71 (0.50–1.02, p = 0.063) | 2.68 (1.14–6.67, p = 0.028) | |
Congestive heart failure | Y | 24 (18.2) | 108 (81.8) | – | – |
N | 164 (29.3) | 395 (70.7) | 0.54 (0.33–0.85, p = 0.010) | 0.78 (0.24–2.37, p = 0.664) | |
Kidney failure | Y | 14 (16.1) | 73 (83.9) | – | – |
N | 174 (28.8) | 430 (71.2) | 0.47 (0.25–0.84, p = 0.014) | 1.85 (0.37–8.24, p = 0.430) | |
Age (y) | 64.3 ± 13.0 | 72.2 ± 10.6 | 1.06 (1.04–1.07, p<0.001) | 1.04 (1.00–1.09, p = 0.064) | |
CCI | 3.7 ± 2.7 | 5.4 ± 2.5 | 1.34 (1.24–1.46, p<0.001) | 1.21 (0.98–1.52, p = 0.096) | |
SOFA | 3.0 ± 1.9 | 4.8 ± 3.0 | 1.42 (1.29–1.57, p<0.001) | 1.66 (1.31–2.20, p<0.001) | |
PaO2/FiO2 (x 10 mmHg) | 16.9 ± 15.5 | 10.1 ± 9.7 | 0.96 (0.94–0.97, p<0.001) | 0.96 (0.92–1.00, p = 0.050) | |
GFR ml/min/1.73 m2 | 84.2 ± 32.0 | 67.9 ± 34.3 | 0.99 (0.98–0.99, p<0.001) | 1.00 (0.99–1.02, p = 0.497) | |
CRP (mg/L/100) | 1.2 ± 1.0 | 1.4 ± 0.8 | 1.28 (1.05–1.58, p = 0.018) | 0.89 (0.58–1.38, p = 0.598) | |
IL6 (pg/ml) | 132.8 ± 314.8 | 251.1 ± 408.7 | 1.00 (1.00–1.00, p = 0.009) | 1.00 (1.00–1.00, p = 0.430) | |
Ferritin (ng/L/100) | 11.5 ± 9.8 | 14.8 ± 12.1 | 1.03 (1.01–1.05, p = 0.004) | 1.03 (0.99–1.07, p = 0.172) | |
D-Dimer (mg/L) | 2.5 ± 1.6 | 2.9 ± 1.5 | 1.16 (1.02–1.31, p = 0.019) | 0.98 (0.77–1.25, p = 0.900) | |
WBC (x109/L) | 11.5 ± 6.1 | 12.9 ± 7.8 | 1.03 (1.00–1.06, p = 0.029) | 1.05 (0.97–1.13, p = 0.218) | |
Neutrophil (%) | 83.0 ± 14.2 | 87.3 ± 11.5 | 1.03 (1.01–1.04, p<0.001) | 1.02 (0.99–1.05, p = 0.208) | |
Lymphocyte (%) | 8.6 ± 7.1 | 6.8 ± 8.4 | 0.98 (0.96–1.00, p = 0.020) | 1.00 (0.95–1.06, p = 0.900) |


Factor | Non-survivors | Survivors | OR and 95% CI (univariable) | OR and 95% CI (multivariable) | |
---|---|---|---|---|---|
Bacterial superinfection | Y | 311 (81.2) | 72 (18.8) | – | – |
N | 192 (62.1) | 117 (37.9) | 2.63 (1.87–3.73, p<0.001) | 1.29 (0.84–1.96, p = 0.232) | |
Mechanical ventilation | Y | 467 (83.8) | 90 (16.2) | – | – |
N | 36 (26.7) | 99 (73.3) | 14.27 (9.24–22.47, p<0.001) | 11.80 (7.40–19.21, p<0.001) | |
RRT | Y | 38 (90.5) | 4 (9.5) | – | – |
N | 465 (71.5) | 185 (28.5) | 3.78 (1.49–12.74, p = 0.013) | 2.50 (0.93–8.85, p = 0.103) | |
Thrombosis | None | 458 (74.2) | 159 (25.8) | – | – |
Peripheral | 16 (80.0) | 4 (20.0) | 0.72 (0.20–2.00, p = 0.562) | 0.98 (0.25–3.06, p = 0.977) | |
CardioPulm | 23 (48.9) | 24 (51.1) | 3.01 (1.65–5.50, p<0.001) | 2.05 (0.98–4.23, p = 0.053) | |
CNS | 6 (75.0) | 2 (25.0) | 0.96 (0.14–4.22, p = 0.961) | 0.79 (0.09–4.57, p = 0.809) | |
HFNO | D | 306 (71.5) | 122 (28.5) | – | – |
N | 197 (74.6) | 67 (25.4) | 0.85 (0.60–1.20, p = 0.370) | 0.85 (0.56–1.29, p = 0.453) |

Factors associated with duration of ICU stay
Factor | HR and 95% CI (univariable) | HR and 95% CI (multivariable) | |
---|---|---|---|
Ward admission | N | 0.86 (0.62–1.18, p = 0.335) | 0.69 (0.49–0.99, p = 0.044) |
DM | N | 0.62 (0.45–0.85, p = 0.004) | 0.69 (0.46–1.03, p = 0.068) |
HA | N | 1.02 (0.73–1.42, p = 0.925) | 1.08 (0.72–1.62, p = 0.717) |
CHF | N | 0.46 (0.30–0.72, p = 0.001) | 0.55 (0.34–0.89, p = 0.015) |
CKD | N | 0.39 (0.25–0.62, p<0.001) | 0.65 (0.37–1.16, p = 0.145) |
Hematological | N | 0.84 (0.46–1.51, p = 0.552) | 1.08 (0.55–2.14, p = 0.817) |
MV | N | 0.12 (0.04–0.37, p<0.001) | 0.12 (0.04–0.39, p<0.001) |
Bacterial superinfection | N | 1.57 (1.09–2.27, p = 0.014) | 2.31 (1.52–3.51, p<0.001) |
Age group | 45–65 | – | – |
65–75 | 1.40 (0.91–2.16, p = 0.122) | 1.60 (0.95–2.70, p = 0.077) | |
<45 | 1.20 (0.47–3.08, p = 0.702) | 0.79 (0.24–2.62, p = 0.703) | |
>75 | 2.40 (1.58–3.64, p<0.001) | 3.46 (2.00–5.99, p<0.001) | |
CCI | 1.12 (1.06–1.18, p<0.001) | 1.01 (0.93–1.10, p = 0.842) | |
WBC | 1.03 (1.00–1.06, p = 0.037) | 1.02 (0.98–1.05, p = 0.306) | |
Neutrophil | 1.01 (0.99–1.02, p = 0.387) | 1.00 (0.99–1.02, p = 0.855) | |
Lymphocyte | 0.99 (0.96–1.02, p = 0.557) | 1.02 (1.00–1.05, p = 0.087) | |
GFR | 0.99 (0.99–1.00, p<0.001) | 1.00 (1.00–1.01, p = 0.334) | |
SOFA | 1.16 (1.11–1.23, p<0.001) | 1.10 (1.02–1.19, p = 0.016) | |
Ferritin | 1.02 (1.01–1.04, p = 0.002) | 1.03 (1.02–1.05, p<0.001) | |
D-Dimer | 1.10 (0.99–1.22, p = 0.068) | 1.12 (0.99–1.27, p = 0.073) | |
PCT | 1.00 (0.99–1.01, p = 0.340) | 0.99 (0.98–1.01, p = 0.228) | |
CRP | 0.98 (0.82–1.17, p = 0.819) | 0.74 (0.58–0.93, p = 0.010) | |
IL-6 | 1.08 (1.05–1.12, p<0.001) | 1.11 (1.06–1.16, p<0.001) |




Discussion
Calligaro G.L., Lalla U., Audley G., et al. The utility of high-flow nasal oxygen for severe COVID-19 pneumonia in a resource-constrained setting: a multi-centre prospective observational study. EClinicalMedicine [Internet]. 2020 Nov 1 [cited 2021 Jun 9];28. Available from: https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(20)30314-X/abstract
Calligaro G.L., Lalla U., Audley G., et al. The utility of high-flow nasal oxygen for severe COVID-19 pneumonia in a resource-constrained setting: a multi-centre prospective observational study. EClinicalMedicine [Internet]. 2020 Nov 1 [cited 2021 Jun 9];28. Available from: https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(20)30314-X/abstract
Službena stranica Vlade za pravodobne i točne informacije o koronavirusu [Internet]. koronavirus.hr. [cited 2020 Apr 19]. Available from: https://www.koronavirus.hr/
Overweight and Obesity – BMI statistics. Eurostat. [Internet]. Available from: https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Overweight_and_obesity_-_BMI_statistics
Weekly new hospital admissions for COVID-19 per million. [Internet]. Available from: https://ourworldindata.org/grapher/weekly-hospital-admissions-covid-per-million?country=DEU∼FRA∼ITA∼ESP∼NLD∼BEL∼HRV∼CYP∼CZE∼DNK∼EST∼GRC∼ISL∼IRL∼LVA∼MLT∼NOR∼SVN
Conclusion
Declaration of Competing Interest

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