Gender differences in incidence and in-hospital outcomes of community-acquired, ventilator-associated and nonventilator hospital-acquired pneumonia in Spain

Aims We aim to compare the incidence and in-hospital outcomes of community-acquired pneumonia (CAP), ventilator-associated pneumonia (VAP) and nonventilator hospital-acquired pneumonia (NV-HAP) according to gender. Methods This was a retrospective observational epidemiological study using the Spanish National Hospital Discharge Database for the years 2016 and 2017. Results Of 277 785 hospital admissions, CAP was identified in 257 455 (41.04% females), VAP was identified in 3261 (30.42% females) and NV-HAP was identified in 17 069 (36.58% females). The incidence of all types of pneumonia was higher amongst males (CAP: incidence rate ratio [IRR] 1.05, 95% CI 1.03-1.06; VAP: IRR 1.36, 95% CI 1.26-1.46; and NV-HAP: IRR 1.16, 95% CI 1.14-1.18). The crude in-hospital mortality (IHM) rate for CAP was 11.44% in females and 11.80% in males (P = .005); for VAP IHM, the rate was approximately 35% in patients of both genders and for NV-HAP IHM, the rate was 23.97% for females and 26.40% for males (P < .001). After multivariable adjustment, in patients of both genders, older age and comorbidities were factors associated with IHM in the three types of pneumonia analysed. Female gender was a risk factor for IHM after VAP (OR 1.24; 95% CI 1.06-1.44), and no gender differences were found for CAP or NV-HAP. Conclusions Our findings show a difference between females and males, with females presenting a lower incidence of all types of pneumonia. However, female gender was a risk factor for IHM after VAP.