Sex-based differences in mortality among a large cohort of hospitalized patients with RT-PCR-confirmed SARS-CoV-2 infection at five different pandemic waves in Northern Iran.

The COVID-19 pandemic has highlighted significant sex-based disparities in mortality, with men often experiencing higher death rates than women. These disparities vary across regions, time, COVID-19 waves, and viral variants (e.g., Alpha, Delta, Omicron). This study aims to analyze sex-specific mortality trends across pandemic waves and COVID-19 related mortality determinants using reverse transcriptase polymerase chain reaction (RT-PCR) confirmed cases. This retrospective cohort study was conducted on a data registry consisting of 44,544 hospitalized COVID-19 patients with positive RT-PCR from 2019 to 2021. Using SPSS version 26, a multiple logistic regression model with adjustment for potential confounders was conducted to calculate the odds ratio (OR) and 95% confidence interval (95%CI) of COVID-19 related death in each variable, both in the total population and separately sorted by sex. A dose-responsive relationship between age, number of comorbidities, and death was observed in the multiple logistic regression model. Certain comorbidities such as diabetes, cancer, cardiac diseases, chronic neurological diseases, and COPD were significantly associated with death. Males were at 17% higher risk of death compared to women (OR: 1.17, 95%CI: 1.09-1.25, P < 0.001) after adjustment for confounders. Compared to the fifth peak, females had 2.35 (95%CI: 1.91-2.89), 1.34 (95%CI: 1.17-1.53), 1.08 (95%CI: 0.95-1.23), and 0.76 (95%CI: 0.65-0.89) times odds of death, whereas males had 2.50 (95%CI: 2.07-3.01), 1.20 (95%CI: 1.05-1.37), 0.98 (95%CI: 0.86-1.12), and 0.78 (95%CI: 0.66-0.91) folds odds of death in the first, second, third, and fourth peaks, respectively. Our results showed that men had higher odds of mortality overall, but there were no significant differences at each peak separately. Also, age and the number of comorbidities demonstrated a significant association with mortality, with possible dose-responsive behavior.