{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T15:02:50Z","timestamp":1776870170335,"version":"3.51.2"},"reference-count":24,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2021,12,26]],"date-time":"2021-12-26T00:00:00Z","timestamp":1640476800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Medical Research Agency","award":["2020\/ABM\/ COVID19\/PTEILCHZ"],"award-info":[{"award-number":["2020\/ABM\/ COVID19\/PTEILCHZ"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Long-term analyses of demographical and clinical characteristics of COVID-19 patients can provide a better overview of the clinical course of the disease. They can also help understand whether changes in infection symptomatology, disease severity, and outcome occur over time. We aimed to analyze the demographics, early symptoms of infection, laboratory parameters, and clinical manifestation of COVID-19 patients hospitalized during the first 17 months of the pandemic in Poland (March 2020\u2013June 2021). The patients\u2019 demographical and clinical data (n = 5199) were extracted from the national SARSTer database encompassing 30 medical centers in Poland and statistically assessed. Patients aged 50\u201364 were most commonly hospitalized due to COVID-19 regardless of the pandemic period. There was no shift in the age of admitted patients and patients who died throughout the studied period. Men had higher C-reactive protein and interleukin-6 levels and required oxygenation and mechanical ventilation more often. No gender difference in fatality rate was seen, although the age of males who died was significantly lower. A share of patients with baseline SpO2 &lt; 91%, presenting respiratory, systemic and gastrointestinal symptoms was higher in the later phase of a pandemic than in the first three months. Cough, dyspnea and fever were more often presented in men, while women had a higher frequency of anosmia, diarrhea, nausea and vomiting. This study shows some shifts in SARS-CoV-2 pathogenicity between March 2020 and July 2021 in the Polish cohort of hospitalized patients and documents various gender-differences in this regard. The results represent a reference point for further analyses conducted under the dominance of different SARS-CoV-2 variants.<\/jats:p>","DOI":"10.3390\/jcm11010117","type":"journal-article","created":{"date-parts":[[2021,12,27]],"date-time":"2021-12-27T01:00:54Z","timestamp":1640566854000},"page":"117","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":28,"title":["Demographic and Clinical Overview of Hospitalized COVID-19 Patients during the First 17 Months of the Pandemic in Poland"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3394-1635","authenticated-orcid":false,"given":"Robert","family":"Flisiak","sequence":"first","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Medical University of Bia\u0142ystok, 15-089 Bialystok, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4713-0801","authenticated-orcid":false,"given":"Piotr","family":"Rzymski","sequence":"additional","affiliation":[{"name":"Department of Environmental Medicine, Poznan University of Medical Sciences, 60-806 Poznan, Poland"},{"name":"Integrated Science Association (ISA), Universal Scientific Education and Research Network (USERN), 60-806 Poznan, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0938-1084","authenticated-orcid":false,"given":"Dorota","family":"Zar\u0119bska-Michaluk","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Jan Kochanowski University, 25-369 Kielce, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Magdalena","family":"Rogalska","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Medical University of Bia\u0142ystok, 15-089 Bialystok, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5318-4945","authenticated-orcid":false,"given":"Marta","family":"Rorat","sequence":"additional","affiliation":[{"name":"Department of Forensic Medicine, Wroc\u0142aw Medical University, 50-367 Wroclaw, Poland"},{"name":"First Infectious Diseases Ward, Gromkowski Regional Specialist Hospital in Wroc\u0142aw, 51-149 Wroclaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Piotr","family":"Czupryna","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Neuroinfections, Medical University of Bia\u0142ystok, 15-089 Bialystok, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6319-9278","authenticated-orcid":false,"given":"Beata","family":"Lorenc","sequence":"additional","affiliation":[{"name":"Pomeranian Center of Infectious Diseases, Department of Infectious Diseases, 80-210 Gdansk, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Przemys\u0142aw","family":"Ciechanowski","sequence":"additional","affiliation":[{"name":"Department of Paediatrics and Infectious Diseases, Regional Hospital in Szczecin, 71-455 Szczecin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4651-6443","authenticated-orcid":false,"given":"Dorota","family":"Kozielewicz","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Faculty of Medicine, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 87-100 Torun, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7188-4881","authenticated-orcid":false,"given":"Anna","family":"Piekarska","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Medical University of \u0141\u00f3d\u017a, 90-549 Lodz, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7783-6904","authenticated-orcid":false,"given":"Maria","family":"Pokorska-\u015apiewak","sequence":"additional","affiliation":[{"name":"Department of Children\u2019s Infectious Diseases, Medical University of Warsaw, 01-201 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5678-5669","authenticated-orcid":false,"given":"Katarzyna","family":"Sikorska","sequence":"additional","affiliation":[{"name":"Department of Tropical Medicine and Epidemiology, Medical University of Gda\u0144sk, 80-210 Gdansk, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Magdalena","family":"Tudrujek","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Medical University of Lublin, 20-059 Lublin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Beata","family":"Bolewska","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Poznan University of Medical Sciences, 61-701 Poznan, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Grzegorz","family":"Angielski","sequence":"additional","affiliation":[{"name":"7th Navy Hospital, 80-305 Gdansk, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1166-4462","authenticated-orcid":false,"given":"Justyna","family":"Kowalska","sequence":"additional","affiliation":[{"name":"Department of Adults\u2019 Infectious Diseases, Medical University of Warsaw, 02-091 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4063-1646","authenticated-orcid":false,"given":"Regina","family":"Podlasin","sequence":"additional","affiliation":[{"name":"Regional Hospital of Infectious Diseases in Warsaw, 01-301 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"W\u0142odzimierz","family":"Mazur","sequence":"additional","affiliation":[{"name":"Clinical Department of Infectious Diseases in Chorz\u00f3w, Medical University of Silesia, 41-500 Katowice, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Barbara","family":"Oczko-Grzesik","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Medical University of Silesia, 40-055 Katowice, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Izabela","family":"Zaleska","sequence":"additional","affiliation":[{"name":"Department of Paediatrics and Infectious Diseases, Wroclaw Medical University, 50-367 Wroclaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Aleksandra","family":"Szymczak","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Liver Diseases and Acquired Immune Deficiencies, Wroclaw Medical University, 51-149 Wroc\u0142aw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paulina","family":"Fra\u0144czak-Chmura","sequence":"additional","affiliation":[{"name":"Department of Children\u2019s Infectious Diseases, Provincial Jan Bo\u017cy Hospital, 20-089 Lublin, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ma\u0142gorzata","family":"Sobolewska-Pilarczyk","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Faculty of Medicine, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 87-100 Torun, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9629-5680","authenticated-orcid":false,"given":"Krzysztof","family":"K\u0142os","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Allergology, Military Institute of Medicine, 04-141 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Magdalena","family":"Figlerowicz","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Child Neurology, Poznan University of Medical Sciences, 60-572 Poznan, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Piotr","family":"Leszczy\u0144ski","sequence":"additional","affiliation":[{"name":"Department of Rheumatology, Rehabilitation and Internal Medicine, Poznan University of Medical Sciences, 61-701 Poznan, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Izabela","family":"Kucharek","sequence":"additional","affiliation":[{"name":"2nd Department of Paediatrics, Centre of Postgraduate Medical Education, 02-507 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hubert","family":"Grabowski","sequence":"additional","affiliation":[{"name":"General, Endocrine and Transplant Surgery Department, Medical University of Gda\u0144sk, 80-214 Gdansk, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,12,26]]},"reference":[{"key":"ref_1","first-page":"157","article-title":"WHO Declares COVID-19 a Pandemic","volume":"91","author":"Cucinotta","year":"2020","journal-title":"Acta Bio-Med. 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