Risk Factors and Mortality of Elderly Patients with Hospital-Acquired Pneumonia of Carbapenem-Resistant Klebsiella pneumoniae Infection

Abstract

Purpose Hospital-acquired pneumonia (HAP) caused by carbapenem-resistant K. pneumoniae (CRKP), especially in elderly patients, results in high morbidity and mortality. Studies on risk factors, mortality, and antimicrobial susceptibility of CRKP pulmonary infection among elderly patients are lacking. Patients and Methods A retrospective case–control study was conducted from January 2019 to December 2021. The elderly inpatients (≥65 years) who were diagnosed with HAP caused by K. pneumoniae were enrolled. Clinical data were collected. Univariate and multivariate logistic regression analyses were used to identify risk factors. Propensity score matching was used to minimize the effect of potential confounding variables. Kaplan–Meier analysis was used to compare survival. Results A total of 115 patients with CRKP infection and 78 patients with carbapenem-susceptible K. pneumoniae (CSKP) infection were recruited. There were four independent risk factors for CRKP infection: history of intensive care unit (ICU) stays from hospital admission to positive respiratory specimen culture for K. pneumoniae (odds ratio (OR)=2.530), Charlson comorbidity index score ≥3 (OR = 2.420), prior exposure to carbapenems (OR = 5.280), and prior K. pneumoniae infection or colonization in the preceding 3 years (OR = 18.529). The all-cause 30-day mortality was 22.3%, the mortality of CRKP and CSKP infection was 28.7% and 12.8%, respectively. Independent risk factors for mortality included: older age (OR = 1.107), immunocompromised patients (OR = 8.632), severe pneumonia (OR = 51.244), quick Sepsis-related Organ Failure Assessment (qSOFA) score ≥2 (OR = 6.187), exposure to tigecycline before infection (OR = 24.702), and prolonged ICU stay (OR = 0.987). Thirty-day mortality was significantly lower in patients receiving ceftazidime-avibactam (CAZ-AVI) containing regimens than patients receiving polymyxin B sulfate (PB) containing regimens (P = 0.048). qSOFA score had a good prognostic effect [area under receiver operating characteristic curve (AUROC) of 0.838]. Conclusion Active screening of CRKP for the high-risk populations, especially elderly patients, is significant for early detection and successful management of CRKP infection.

Risk Factors and Outcomes of Community-Acquired Carbapenem-Resistant Klebsiella pneumoniae Infection in Elderly Patients

“…Notably, past studies regarding CRKP infection in elderly patients mainly focused on hospital-acquired issues, whereas approximately 0.04–29.5% of carbapenem-resistant pathogens were reported to be of community-origin, and the trend is continually rising [ 20 ]. Our study provides evidence that patients with community-acquired CRKP infection may present similar hospital-acquired clinical characteristics and outcomes and reminds clinicians of the threat of community-acquired resistant-pathogens [ 10 , 11 , 13 ].…”

“…Previous studies of CRKP infection in elderly patients have mainly focused on its association with mortality risk [ 10 , 11 ]. Our study highlights that the patients with CRKP infection also had a significantly higher risk of other adverse outcomes, including ICU care, respiratory failure, and septic shock, which correlated with disease severity (i.e., SOFA score).…”

“…K. pneumoniae is one of the most common causative microorganisms in elderly patients with infections, especially in patients with respiratory tract and bloodstream infections [ 10 , 11 ]. Moreover, higher morbidity and mortality rates were observed for infections sustained by multidrug resistant strains, due to the reduced therapeutic options [ 11 ].…”

“…K. pneumoniae is one of the most common causative microorganisms in elderly patients with infections, especially in patients with respiratory tract and bloodstream infections [ 10 , 11 ]. Moreover, higher morbidity and mortality rates were observed for infections sustained by multidrug resistant strains, due to the reduced therapeutic options [ 11 ]. Elderly patients not only have a higher risk of infectious disease, but are also easily colonized by multi-drug resistant strains, particularly those caused by K. pneumoniae in those with multiple comorbidities [ 12 ].…”

“…Elderly patients not only have a higher risk of infectious disease, but are also easily colonized by multi-drug resistant strains, particularly those caused by K. pneumoniae in those with multiple comorbidities [ 12 ]. Extensive studies have focused on the risk factors for hospital-acquired CRKP infection in elderly patients in recent years, revealing that prior antibiotic administration (e.g., cephalosporin, fluoroquinolone, and carbapenems), comorbidities (e.g., diabetes mellitus, malignancy, and cardiovascular disease), and medical interventions (e.g., mechanical ventilation and central venous catheter insertion) were common risk factors [ 11 , 13 ]. Notably, few studies have investigated the risk factors and outcomes of community-acquired CRKP in this frail population.…”