Comparative analysis of the prognostic significance of the CURB-65 and CRB-65 scores and their modifications in hospital mortality assessment in patients with community-acquired pneumonia

Background. Mortality associated with community-acquired pneumonia (CAP) continues to be a crucial health problem worldwide. Correct assessment of CAP severity and the level of care is pivotal in the disease outcome.

Aim. To evaluate the prognostic value of the CURB-65 and CRB-65 scores and their modifications in determining the risk of in-hospital mortality in patients with CAP.

Materials and methods. The retrospective study included 1,412 patients with CAP aged over 18 years. In a population of 1,020 patients, which was subsequently split into test (n = 676) and training (n = 344) samples in the ratio 2 : 1, we compared the predictive value of the CURB-65 (confusion, urea > 7 mmol / l, respiratory rate ≥ 30 / min, low blood pressure (BP), and age ≥ 65 years) and CRB-65 (confusion, respiratory rate ≥ 30 / min, low blood pressure (BP), and age ≥ 65 years) scores in identifying patients at high risk of in-hospital death. The specified scoring systems were modified by changing the cut-offs for each criterion to increase their accuracy. For comparison, we used the ROC analysis with the calculation of the area under the curve (AUC).

Results. The modified CURB-65 score with new cut-off values (age > 72 years, respiratory rate > 21 / min, urea level > 9.5 mmol / l, systolic blood pressure ≤ 105 mm Hg, and diastolic blood pressure ≤ 65 mm Hg) was more accurate than the original one in predicting death and was named CURB-72. The AUC for CURB-72 and CURB-65 was 0.946 (95% confidence interval (CI): 0.916–0.967) and 0.905 (95% CI: 0.869–0.934), respectively (p = 0.0034). The modified CRB-65 (CRB-72) score also outperformed the original model, but showed no statistically significant difference. While comparing the modified scoring systems, the new CURB-72 score surpassed the CRB-72 score and demonstrated maximum accuracy in identifying CAP patients at risk of in-hospital mortality (p = 0.0347).

Conclusion. The modified CURB-65 (CURB-72) and CRB-65 (CRB-72) scores demonstrated potential for assessing the prognosis of CAP and are superior to classical scoring systems. CURB-72 showed the highest sensitivity and specificity.

1. Prina E., Ranzani O.T., Torres A. Community-acquired pneumonia. Lancet. 2015;386(9998):1097–1108. DOI: 10.1016/S0140-6736(15)60733-4.

2. Torres A., Cillóniz C., Blasi F., Chalmers J.D., Gaillat J., Dartois N. et al. Burden of pneumococcal community-acquired pneumonia in adults across Europe: A literature review. Respiratory Medicine. 2018;137:6–13. DOI: 10.1016/j.rmed.2018.02.007.

3. GBD 2016 Lower Respiratory Infections Collaborators. Estimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory infections in 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Infect. Dis. 2018;18(11):1191–1210. DOI: 10.1016/S1473-3099(18)30310-4.

4. Всемирная организация здравоохранения. 10 основных причин смерти. Всемирная организация здравоохранения: Женева, Швейцария, 2019 г. URL: https://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death (дата обращения: 01.12.2023).

5. Fine M.J., Auble T.E., Yealy D.M., Hanusa B.H., Weissfeld L.A., Singer D.E. et al. A prediction rule to identify low-risk patients with community-acquired pneumonia. The New England Journal of Medicine. 1997;336(4):243–250. DOI: 10.1056/NEJM199701233360402.

6. Lim W.S., van der Eerden M.M., Laing R., Boersma W.G., Karalus N., Town G.I. et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax. 2003;58(5):377–382. DOI: 10.1136/thorax.58.5.377.

7. Рачина С.А., Дехнич Н.Н., Козлов Р.С., Бобылев А.А., Батищева Г.А., Гордеева С.А. и др. Оценка тяжести внебольничной пневмонии в реальной клинической практике в многопрофильных стационарах Российской Федерации. Пульмонология. 2016;26(5):521–528. DOI: 10.18093/0869-0189-2016-26-5-521-528.

8. Serisier D.J., Williams S., Bowler S.D. Australasian respiratory and emergency physicians do not use the pneumonia severity index in community-acquired pneumonia. Respirology (Carlton, Vic.). 2013;18(2):291–296. DOI: 10.1111/j.1440-1843.2012.02275.x.

9. Ilg A., Moskowitz A., Konanki V., Patel P.V., Chase M., Grossestreuer A.V. et al. Performance of the CURB-65 Score in predicting critical care interventions in patients admitted with community-acquired pneumonia. Annals of Emergency Medicine. 2019;74(1):60–68. DOI: 10.1016/j.annemergmed.2018.06.017.

10. Hincapié C., Ascuntar J., León A., Jaimes F. Community-acquired pneumonia: comparison of three mortality prediction scores in the emergency department. Colombia Medica (Cali, Colombia). 2021;52(4):e2044287. DOI: 10.25100/cm.v52i4.4287.

11. Ebell M.H., Walsh M.E., Fahey T., Kearney M., Marchello C. Meta-analysis of Calibration, Discrimination, and Stratum-Specific Likelihood Ratios for the CRB-65 Score. Journal of General Internal Medicine. 2019;34(7):1304–1313. DOI: 10.1007/s11606-019-04869-z.

12. Al Hussain S.K., Kurdi A., Abutheraa N., Al Dawsari A., Sneddon J., Godman B. et al. Validity of Pneumonia Severity Assessment Scores in Africa and South Asia: A Systematic Review and Meta-Analysis. Healthcare (Basel, Switzerland). 2021;9(9):1202. DOI: 10.3390/healthcare9091202.

13. Fernandes L., Arora A.S., Mesquita A.M. Role of semi-quantitative serum procalcitonin in assessing prognosis of community acquired bacterial pneumonia compared to PORT PSI, CURB-65 and CRB-65. Journal of Clinical and Diagnostic Research: JCDR. 2015;9(7):OC01–OC4. DOI: 10.7860/JCDR/2015/12468.6147.

14. Chalmers J.D., Singanayagam A., Akram A.R., Mandal P., Short P.M., Choudhury G. et al. Severity assessment tools for predicting mortality in hospitalised patients with community-acquired pneumonia. Systematic review and meta-analysis. Thorax. 2010;65(10):878–883. DOI: 10.1136/thx.2009.133280.

15. Li H.Y., Guo Q., Song W.D., Zhou Y.P., Li M., Chen X.K. et al. CUR-65 Score for community-acquired pneumonia predicted mortality better than CURB-65 score in low-mortality rate settings. The American Journal of the Medical Sciences. 2015;350(3):186–190. DOI: 10.1097/MAJ.0000000000000545.

16. Guo Q., Li H.Y., Song W.D., Li M., Chen X.K., Liu H. et al. Updating cut-off values of severity scoring systems for community-acquired pneumonia to orchestrate more predictive accuracy. Annals of Medicine. 2023;55(1):62202414. DOI: 10.1080/07853890.2023.2202414.