Document Type : Research Article


Shiraz Nephro-Urology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran


Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a highly contagious disease, which led to a pandemic health emergency. However, age distribution and sex, regarding factors affecting the severity of COVID-19, are controversial. Therefore, this study is designed to investigate the effect of gender difference on the severity of COVID-19 infection in the studied age groups.
Methods: Patients with COVID-19 of Valiasr Hospital (Khorrambid, Fars, Iran) from February 20, 2020, to February 20, 2021, are included in this retrospective study. The inclusion criteria were the age of above 15 years old and being residents of Khorrambid. COVID‐19 severity was classified as mild and moderate/severe according to the WHO standards. The obtained demographical and clinical data from the patient registry forms were analyzed using SPSS-24; P value <0.05 was considered as the level of significance. Chi-square and independent t-test were used to assess the variables.
Results: Herein, 218 patients were recruited with a mean age of 45.6±17.2 and a relatively equal distribution of men and women population. Out of this population, 23.8% had comorbid diseases, 48.2% had mild, and 51.8% had moderate/severe infections. Our results indicated that male gender and the age range of 25-64 years in men are the most important risk factors associated with the disease severity (P<0.0001).
Conclusions: The current study revealed that the leading risk factor of the disease severity was higher age (≥65 years) in the studied women. Meanwhile, in the men group, this factor was the age range of 25-64 years. These results suggest that further research is required to identify the possible impacts of gender and age on various aspects of the ongoing epidemic.


1. Huang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020;395(10223):497-506. doi: 10.1016/S0140-6736(20)30183-5. PubMed PMID: 31986264; PubMed Central PMCID: PMCPMC7159299. ## 2. Zhou F, Yu T, Du R, Fan G, Liu Y, Liu Z, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet. 2020;395(10229):1054-1062. doi: 10.1016/S0140-6736(20)30566-3. PubMed PMID: 32171076; PubMed Central PMCID: PMCPMC7270627. ## 3. Zhu N, Zhang D, Wang W, Li X, Yang B, Song J, et al. A novel coronavirus from patients with pneumonia in China, 2019. N Engl J Med. 2020;382(8):727-733. doi: 10.1056/NEJMoa2001017. PubMed PMID: 31978945; PubMed Central PMCID: PMCPMC7092803. ## 4. Cheng Y, Luo R, Wang K, Zhang M, Wang Z, Dong L, et al. Kidney disease is associated with in-hospital death of patients with COVID-19. Kidney Int. 2020;97(5):829-838. doi: 10.1016/j.kint.2020.03.005. PubMed PMID: 32247631; PubMed Central PMCID: PMCPMC7110296. ## 5. Chen N, Zhou M, Dong X, Qu J, Gong F, Han Y, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study. Lancet. 2020;395(10223):507-513. doi: 10.1016/S0140-6736(20)30211-7. PubMed PMID: 32007143; PubMed Central PMCID: PMCPMC7135076. ## 6. Chan JF-W, Yuan S, Kok K-H, To KK-W, Chu H, Yang J, et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet. 2020;395(10223):514-523. doi: 10.1016/S0140-6736(20)30154-9. PubMed PMID: 31986261; PubMed Central PMCID: PMCPMC7159286. ## 7. Naicker S, Yang C-W, Hwang S-J, Liu B-C, Chen J-H, Jha V. The Novel Coronavirus 2019 epidemic and kidneys. Kidney Int. 2020;97(5):824-828. doi: 10.1016/j.kint.2020.03.001. PubMed PMID: 32204907; PubMed Central PMCID: PMCPMC7133222. ## 8. Jin J-M, Bai P, He W, Wu F, Liu X-F, Han D-M, et al. Gender Differences in Patients With COVID-19: Focus on Severity and Mortality. Front Public Health. 2020;8:152. doi: 10.3389/fpubh.2020.00152. PubMed PMID: 32411652; PubMed Central PMCID: PMCPMC7201103. ## 9. Centers for Disease Control and Prevention Coronavirus Disease 2019 (COVID-19); 2022. Available from: ## 10. Karimi Z, Masjedi F, Malekmakan L, Doostkam A, Roozbeh J, Ghahramani N. Potential Mechanisms of the SARS-CoV-2-induced AKI Progression to CKD: A Forward-Looking Perspective. Iran J Kidney Dis. 2021;15(4):243-255. PubMed PMID: 34278995. ## 11. Capuano A, Rossi F, Paolisso G. Covid-19 Kills More Men Than Women: An Overview of Possible Reasons. Front Cardiovasc Med. 2020;7:131. doi: 10.3389/fcvm.2020.00131. PubMed PMID: 32766284; PubMed Central PMCID: PMCPMC7380096. ## 12. Liu R, Han H, Liu F, Lv Z, Wu K, Liu Y, et al. Positive rate of RT-PCR detection of SARS-CoV-2 infection in 4880 cases from one hospital in Wuhan, China, from Jan to Feb 2020. Clin Chim Acta. 2020;505:172-175. doi: 10.1016/j.cca.2020.03.009. PubMed PMID: 32156607; PubMed Central PMCID: PMCPMC7094385. ## 13. Fisman DN, Greer AL, Brankston G, Hillmer M, O'Brien SF, Drews SJ, et al. COVID-19 Case Age Distribution: Correction for Differential Testing by Age. Ann Intern Med. 2021;174(10):1430-1438. doi: 10.7326/m20-7003. PubMed PMID: 34399059; PubMed Central PMCID: PMCPMC8381772. ## 14. Caini S, Spreeuwenberg P, Kusznierz GF, Rudi JM, Owen R, Pennington K, et al. Distribution of influenza virus types by age using case-based global surveillance data from twenty-nine countries, 1999-2014. BMC Infect Dis. 2018;18(1):269. doi: 10.1186/s12879-018-3181-y. PubMed PMID: 29884140; PubMed Central PMCID: PMCPMC5994061. ## 15. Jansen A, Chiew M, Konings F, Lee CK, Ailan L. Sex matters - a preliminary analysis of Middle East respiratory syndrome in the Republic of Korea, 2015. Western Pac Surveill Response J. 2015;6(3):68-71. doi: 10.5365/wpsar.2015.6.3.002. PubMed PMID: 26668769; PubMed Central PMCID: PMCPMC4675154. ## 16. Fenollar-Cortés J, Jiménez Ó, Ruiz-García A, Resurrección DM. Gender Differences in Psychological Impact of the Confinement During the COVID-19 Outbreak in Spain: A Longitudinal Study. Front Psychol. 2021;12:682860. doi: 10.3389/fpsyg.2021.682860. PubMed PMID: 34248784; PubMed Central PMCID: PMCPMC8264415. ## 17. Cao B, Wang Y, Wen D, Liu W, Wang J, Fan G, et al. A Trial of Lopinavir-Ritonavir in Adults Hospitalized with Severe Covid-19. N Engl J Med. 2020;382(19):1787-1799. doi: 10.1056/NEJMoa2001282. PubMed PMID: 32187464; PubMed Central PMCID: PMCPMC7121492. ## 18. Age Categories, Life Cycle Groupings Canada: Statistics Canada; 2017. Available from: ## 19. Wang D, Hu B, Hu C, Zhu F, Liu X, Zhang J, et al. Clinical Characteristics of 138 Hospitalized Patients With 2019 Novel Coronavirus–Infected Pneumonia in Wuhan, China. JAMA. 2020;323(11):1061-1069. doi: 10.1001/jama.2020.1585. PubMed PMID: 32031570; PubMed Central PMCID: PMCPMC7042881. ## 20. Pan L, Mu M, Yang P, Sun Y, Wang R, Yan J, et al. Clinical Characteristics of COVID-19 Patients With Digestive Symptoms in Hubei, China: A Descriptive, Cross-Sectional, Multicenter Study. Am J Gastroenterol. 2020;115(5):766-773. doi: 10.14309/ajg.0000000000000620. PubMed PMID: 32287140; PubMed Central PMCID: PMCPMC7172492. ## 21. To KK-W, Tsang OT-Y, Leung W-S, Tam AR, Wu T-C, Lung DC, et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study. Lancet Infect Dis. 2020;20(5):565-574. doi: 10.1016/S1473-3099(20)30196-1. PubMed PMID: 32213337; PubMed Central PMCID: PMCPMC7158907. ## 22. Lian J, Jin X, Hao S, Jia H, Cai H, Zhang X, et al. Epidemiological, clinical, and virological characteristics of 465 hospitalized cases of coronavirus disease 2019 (COVID-19) from Zhejiang province in China. Influenza Other Respir Viruses. 2020;14(5):564-574. doi: 10.1111/irv.12758. PubMed PMID: 32397011; PubMed Central PMCID: PMCPMC7273099. ## 23. Chen J, Qi T, Liu L, Ling Y, Qian Z, Li T, et al. Clinical progression of patients with COVID-19 in Shanghai, China. J Infect. 2020;80(5):e1-e6. doi: 10.1016/j.jinf.2020.03.004. PubMed PMID: 32171869; PubMed Central PMCID: PMCPMC7102530. ## 24. Richardson S, Hirsch JS, Narasimhan M, Crawford JM, McGinn T, Davidson KW, et al. Presenting Characteristics, Comorbidities, and Outcomes Among 5700 Patients Hospitalized With COVID-19 in the New York City Area. JAMA. 2020;323(20):2052-2059. doi: 10.1001/jama.2020.6775. PubMed PMID: 32320003; PubMed Central PMCID: PMCPMC7177629. ## 25. Medetalibeyoğlu A, Şenkal N, Çapar G, Köse M, Tükek T. Characteristics of the initial patients hospitalized for COVID-19: a single-center report. Turk J Med Sci. 2020;50(5):1436-1439. doi: 10.3906/sag-2004-98. PubMed PMID: 32490641; PubMed Central PMCID: PMCPMC7491264. ## 26. Nikpouraghdam M, Jalali Farahani A, Alishiri G, Heydari S, Ebrahimnia M, Samadinia H, et al. Epidemiological characteristics of coronavirus disease 2019 (COVID-19) patients in IRAN: A single center study. J Clin Virol. 2020;127:104378. doi: 10.1016/j.jcv.2020.104378. PubMed PMID: 32353762; PubMed Central PMCID: PMCPMC7172806. ## 27. Shahriarirad R, Khodamoradi Z, Erfani A, Hosseinpour H, Ranjbar K, Emami Y, et al. Epidemiological and clinical features of 2019 novel coronavirus diseases (COVID-19) in the South of Iran. BMC Infect Dis. 2020;20(1):427. doi: 10.1186/s12879-020-05128-x. PubMed PMID: 32552751; PubMed Central PMCID: PMC7301075. ## 28. Bhattacharjee S, Banerjee M, Pal R. ABO blood groups and severe outcomes in COVID-19: A meta-analysis. Postgrad Med J. 2022;98(e2):e136-e137. doi: 10.1136/postgradmedj-2020-139248. PubMed PMID: 35232874. ## 29. Zhu J, Ji P, Pang J, Zhong Z, Li H, He C, et al. Clinical characteristics of 3062 COVID-19 patients: A meta-analysis. J Med Virol. 2020;92(10):1902-1914. doi: 10.1002/jmv.25884. PubMed PMID: 32293716; PubMed Central PMCID: PMCPMC7262119. ## 30. Xu YH, Dong JH, An WM, Lv XY, Yin XP, Zhang JZ, et al. Clinical and computed tomographic imaging features of novel coronavirus pneumonia caused by SARS-CoV-2. J Infect. 2020;80(4):394-400. doi: 10.1016/j.jinf.2020.02.017. PubMed PMID: 32109443; PubMed Central PMCID: PMCPMC7102535. ## 31. Wang X, Fang J, Zhu Y, Chen L, Ding F, Zhou R, et al. Clinical characteristics of non-critically ill patients with novel coronavirus infection (COVID-19) in a Fangcang Hospital. Clin Microbiol Infect. 2020;26(8):1063-1068. doi: 10.1016/j.cmi.2020.03.032. PubMed PMID: 32251842; PubMed Central PMCID: PMCPMC7195539. ## 32. Huang X, Wei F, Hu L, Wen L, Chen K. Epidemiology and Clinical Characteristics of COVID-19. Arch Iran Med. 2020;23(4):268-271. doi: 10.34172/aim.2020.09. PubMed PMID: 32271601. ## 33. Hassan SA, Sheikh FN, Jamal S, Ezeh JK, Akhtar A. Coronavirus (COVID-19): A Review of Clinical Features, Diagnosis, and Treatment. Cureus. 2020;12(3):e7355. doi: 10.7759/cureus.7355. PubMed PMID: 32328367; PubMed Central PMCID: PMCPMC7170025. ## 34. Bhopal SS, Bhopal R. Sex differential in COVID-19 mortality varies markedly by age. Lancet. 2020;396(10250):532-533. doi: 10.1016/S0140-6736(20)31748-7. PubMed PMID: 32798449; PubMed Central PMCID: PMCPMC7426105. ## 35. National Institute for Demographic Studies. Demographics of COVID-19 deaths: data and metadata. Available from: 36. Acheampong DO, Barffour IK, Boye A, Aninagyei E, Ocansey S, Morna MT. Male predisposition to severe COVID-19: Review of evidence and potential therapeutic prospects. Biomed Pharmacother. 2020;131:110748. doi: 10.1016/j.biopha.2020.110748. PubMed PMID: 33152916; PubMed Central PMCID: PMCPMC7480230. ## 37. Haghpanah A, Masjedi F, Alborzi S, Hosseinpour A, Dehghani A, Malekmakan L, et al. Potential mechanisms of SARS-CoV-2 action on male gonadal function and fertility: Current status and future prospects. Andrologia. 2021;53(1):e13883. doi: 10.1111/and.13883. PubMed PMID: 33108833; PubMed Central PMCID: PMCPMC7645932. ## 38. Haghpanah A, Masjedi F, Salehipour M, Hosseinpour A, Roozbeh J, Dehghani A. Is COVID-19 a risk factor for progression of benign prostatic hyperplasia and exacerbation of its related symptoms?: a systematic review. Prostate Cancer Prostatic Dis. 2022;25(1):27-38. doi: 10.1038/s41391-021-00388-3. PubMed PMID: 34007019; PubMed Central PMCID: PMCPMC8129694. ##