Factors Affecting Poor Outcomes in Hospital-Acquired Pneumonia Patients Followed in the Intensive Care Unit: A Retrospective Cohort Study

Abstract

Factors Affecting Poor Outcomes in Hospital-Acquired Pneumonia Patients Followed in the Intensive Care Unit: A Retrospective Cohort Study

Abstract

Purpose: Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are significant public health problems worldwide. The aim of this study was to determine the etiological pathogens, susceptibility distribution, and parameters that may indicate poor prognosis in patients diagnosed with HAP/VAP and followed up in the intensive care unit (ICU). Materyal-Metod: This study was designed as a retrospective cohort study. Demographic characteristics, causative microorganisms, susceptibility profiles of these pathogens, and 28-day mortality data (all-cause) of patients diagnosed with HAP and VAP who were hospitalized in the ICU were retrospectively reviewed from patient files. At the end of the 28-day period, patients were divided into survivor and non-survivor groups based on their survival status. Clinical parameters were compared between the two groups. Results: This study included 142 patients diagnosed with HAP who were followed up at ICU. Of these, 102 (71.8%) patients were diagnosed with ventilator-associated pneumonia (VAP). The median age of the cohort was 72 years (IQR: 65–79), and 73.9% were male. The frequency of concomitant malignancy (43.0% vs 25.0%, p=0.029), WBC values at the onset of pneumonia [median 15.2 (IQR: 9.8–20.9) vs 11.9 (IQR: 8.6–14.4), p=0.010], procalcitonin levels [median 0.9 [(IQR: 0.3–5.3) vs 0.3 (IQR: 0.1–1.4) p=0.003], and the frequency of bacteremia secondary to pneumonia (39.5% vs 8.9% p<0.001) were found to be statistically significantly higher in the non-survivor group compared to the survivor group. The highest carbapenem resistance was detected in K. pneumonia (95.54%). The 28-day mortality rate was 60.6%. In multivariate analysis, concomitant bacteremia was independently associated with 28-day mortality (OR: 6.98, 95% CI: 2.37–20.54, p<0.001). Conclusion: Mortality rates are high in HAP and VAP patients followed in the ICU. The development of bacteremia secondary to pneumonia is an independent risk factor for mortality.

Keywords

• hospital-acquired pneumonia
• ventilator-associated pneumonia
• mortality

References

1. Jain S, Self WH, Wunderink RG, et al.; CDC EPIC StudyTeam. Community-acquired pneumonia requiring hos-pitalization among U.S. adults. N Engl J Med 2015;373:415–427.
2. Muessig JM, Masyuk M, Nia AM, et al. Are we evertoo old? Characteristics and outcome of octogenar-ians admitted to a medical intensive care unit.Medicine 2017;96:e7776.
3. Jain V, Vashisht R, Yilmaz G, Bhardwaj A. Pneumonia pathology. Treasure Island, FL: StatPearls Publishing; 2021.
4. Kalil AC, Metersky ML, Klompas M, et al: Management of adults with hospital-acquired and ventilator-associated pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society. Clin Infect Dis 2016; 63:e61–e111.
5. Giuliano KK, Baker D, Quinn B. The epidemiology of nonventilator hospital-acquired pneumonia in the United States. Am J Infect Control 2018;46(3):322–7.
6. Herkel T, Uvizl R, Doubravska L, et al. Epidemiology of hospital-acquired pneumonia: Results of a Central European multicenter, prospective, observational study compared with data from the European region. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2016;160:448–55.
7. Schwebel C, Reignier J, Kallel H, et al. A comparison of the mortality risk associated with ventilator-acquired bacterial pneumonia and nonventilator ICU-acquired bacterial pneumonia. Crit Care Med 2018;1:346.
8. Bakhru RN, Wiebe DJ, McWilliams DJ, Spuhler VJ, Schweickert WD. An environmental scan for early mobilization practices in U.S. ICUs. Crit Care Med 2015;43(11):2360–2369.

9. Melsen WG, Rovers MM, Groenwold RH, et al. Attributable mortality of ventilator-associated pneumonia: a meta-analysis of individual patient data from randomised prevention studies. Lancet Infect Dis 2013;13(08):665–671.
10. Torres A, Niederman MS, Chastre J, et al. International ERS/ESICM/ESCMID/ALAT guidelines for the management of hospital-acquired pneumonia and ventilator-associated pneumonia: Guidelines for the management of hospital-acquired pneumonia (HAP)/ventilator-associated pneumonia (VAP) of the European Respiratory Society (ERS), European Society of Intensive Care Medicine (ESICM), European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and Asociación Latinoamericana del Tórax (ALAT). Eur Respir J 2017;50(03):1700582
11. Koulenti D, Tsigou E, Rello J. Nosocomial pneumonia in 27 ICUs in Europe: perspectives from the EU-VAP/CAP study. Eur J Clin Microbiol Infect Dis 2017;36(11):1999–2006
12. Jim Neill. Antimicrobial Resistance Tackling a crisis for the health and wealth of nations. Review on Antimicrobial Resistance Dec. 2014. available from: https://amr-review.or g/sites/default/files/AMR%20Review%20Paper%20-%20Tackling%20a%20crisis %20for%20the%20health%20and%20wealth%20of%20nations_1.pdf date:15.06.2025.
13. Diseases and Organisms in Healthcare Settings. (2019). Available from: https://www.cdc.gov/hai/organisms/organisms.ht ml. Date:20.05.2025.
14. Dickstein Y, Lellouche J, Ben Dalak Amar M, et al. Treatment Outcomes of Colistin- and Carbapenem-resistant Acinetobacter baumannii Infections: An Exploratory Subgroup Analysis of a Randomized Clinical Trial. Clin Infect Dis 2019;69:769–76.
15. Magiorakos AP, Srinivasan A, Carey RB, Carmeli Y, Falagas ME, Giske CG, et al. Multidrug-resistant, extensively drugresistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clin Microbiol Infect 2012;18:268-81.
16. Oznur E, Guzeldag S, Cakir N. Evaluating causative agents, mortality factors, and laboratory data of hospital-acquired pneumonia patients. Rev Assoc Med Bras (1992). 2021;67(12):1846-1851.
17. Zhou XY, Ben SQ, Chen HL, Ni SS. A comparison of Apache II and CPIS scores for the prediction of 30-day mortality in patients with ventilator-associated pneumonia. Int J Infect Dis. 2015:30:144-7.
18. Goto A, Ishikawa K, Komiya K. A systematic review of factors associated with poor prognosis despite appropriate antibiotics usage for pneumonia. Respir Investig. 2024;62(6):1215-1219.
19. Türk Torax Derneği Erişkinlerde Hastanede Gelişen Pnömoni Tanı ve Tedavi Uzlaşı Raporu 2018. Avaible from: https://toraks.org.tr/site/sf/books/pre_migration/4500cdf26926c6f5cc9f197b8f8dfa92639c96046aff8b9866b60be3e001a366.pdf date: 20.06.2025
20. Giacobbe DR, Battaglini D, Enrile EM, et al.: Incidence and Prognosis of Ventilator-Associated Pneumonia in Critically Ill Patients with COVID-19: A Multicenter Study. J. Clin. Med 2021; 10(4): 555.
21. Poovieng J, Sakboonyarat B, Nasomsong W. Bacterial etiology and mortality rate in community-acquired pneumonia, healthcare-associated pneumonia and hospital-acquired pneumonia in Thai university hospital. Sci Rep. 2022;12(1):9004.
22. Hoşgün D, Aydemir S. Factors affecting 90-day mortality in community and hospital acquired pneumonia patients with or without acute kidney injury. Afr Health Sci 2022;22(3):567-577.
23. Siempos II, Vardakas KZ, Kyriakopoulos CE, Ntaidou TK, Falagas ME. Predictors of mortality in adult patients with ventilator-associated pneumonia: a metaanalysis. Shock 2010;33:590–601.
24. Huang F, Shen T, Hai X, et al. Clinical characteristics of and risk factors for secondary bloodstream infection after pneumonia among patients infected with methicillin-resistant Staphylococcus aureus. Heliyon 2022;8(12):e11978.
25. Chen J, Li J, Huang F, et al. Clinical characteristics, risk factors and outcomes of Klebsiella pneumoniae pneumonia developing secondary Klebsiella pneumoniae bloodstream infection. BMC Pulm Med 2023;23(1):102.