Assessing sex differential in COVID-19 mortality rate by age and polymerase chain reaction test results: an Iranian multi-center study

Background Males are more likely to die from COVID-19 than females. In addition, the mortality rate among positive and suspected COVID-19 patients were reported in many studies. The aim of this study is to evaluate the sex differential effect in the COVID-19 mortality by different age groups and polymerase chain reaction (PCR) test results. Research design In a multicenter cross-sectional study from 55 hospitals in Tehran, Iran, patients were categorized as positive, negative and suspected cases. Age group, sex and hospital wards were also assessed in the analysis. Results A total of 25481 cases (14791 males) were included in the study with a mortality rate of 12.0%. The mortality rates in positive, negative and suspected cases were 20.55%, 9.97% and 7.31%, respectively. Although the mortality in negative test group was considerable, sex was not associated with the death rate in this group. Using a Cox regression model, sex had a significant effect on the hazard of death due to COVID-19 in adult and senior male patients having positive and suspected PCR test results. However, sex was not found as significant factor for mortality in patients with a negative PCR test in different age groups. Conclusions Regardless of other risk factors, we found that the effect of sex on COVID-19 mortality varied significantly in different age groups. Therefore, appropriate strategies should be designed to protect adult and senior males from this deadly infectious disease. Furthermore, owing to the considerable death rate of COVID-19 patients with negative test results, new policies should be launched to increase the accuracy of diagnosis tests.