Response to "Letter to the Editor: Coronavirus disease 2019 (COVID-19) markedly increased mortality in patients with hip fracture: A systematic review and meta-analysis".

The pooled prevalence of COVID-19 of 9% [95% CI: 7%–11%] in the manuscript is referring to the fixed effect, while the prevalence of COVID-19 of 16% 995% CI: 8%–24%) is referring to the random effect. The use of random effect is more accurate than fixed effect.

Regarding the prevalence of 13.8% (76 COVID-19 positive patients from a pooled cohort of 552 hip fracture patients), this figure represents a rough estimate of prevalence. However, in a meta-analysis, data were assigned a weighted per study rather than simply divide the number of positive cases per total cohort.

Regarding the rate of COVID-19 by sex, male subjects were obviously shown to have greater mortality rate than female subjects. Being females increases their risk of developing osteoporosis, which is one of the risk factor that may explain the mechanism of fracture. In contrary, the male population may require high-energy trauma or the presence of pathologies to suffer a fracture, therefore they may possess comorbidities or accompanying pathologies that put them at increased risk of death. We did not perform sex-related meta-analysis, considering that males were clearly have a higher prevalence and mortality rate than females. Additionally, we did not have individual patient data and the number of studies was too small for the study level to conduct meta regression.