C-reactive protein to albumin ratio as a prognostic marker in community-acquired pneumonia mortality

Year 2025, Volume: 16 Issue: 1, 180 - 185, 25.03.2025

İzzet Ustaalioğlu , Özge Kibici

https://doi.org/10.18663/tjcl.1640626

Abstract

Aim: This study aimed to evaluate the prognostic value of the C-reactive protein-to-albumin ratio (CAR) in predicting 30-day mortality among patients diagnosed with community-acquired pneumonia (CAP) presenting to the emergency department (ED).
Material and Methods: A retrospective study was conducted on 312 patients diagnosed with CAP who presented to the ED of a tertiary care hospital between January 1, 2022, and January 1, 2024. Demographic, clinical, and laboratory data were collected, including C-reactive protein (CRP) and albumin levels. CAR was calculated by dividing CRP levels (mg/dL) by albumin levels (g/L). The primary outcome was 30-day mortality. The prognostic performance of CAR was evaluated using receiver operating characteristic (ROC) curve analysis.
Results: Of the 312 patients included, 87 (27.9%) died within 30 days. The deceased group had significantly higher CAR values compared to survivors (1.18 ± 0.62 vs. 0.52 ± 0.25, p < 0.001). CAR demonstrated excellent discriminatory power for predicting 30-day mortality, with an area under the curve (AUC) of 0.837 (95% CI: 0.791–0.876, p < 0.001). At a cut-off value of >0.77, CAR achieved a sensitivity of 75.9% and a specificity of 86.7%. Deceased patients also exhibited significantly lower systolic and diastolic blood pressures, oxygen saturation, and albumin levels, along with higher CRP levels and respiratory rates. Comorbidities such as stroke and congestive heart failure were more prevalent in the deceased group compared to survivors.
Conclusion: The C-reactive protein-to-albumin ratio is a reliable prognostic marker for predicting 30-day mortality in CAP patients presenting to the ED. Its ease of calculation and strong discriminatory power make CAR a valuable tool for risk stratification and clinical decision-making. Prospective studies are warranted to confirm these findings in diverse populations.

Keywords

albumin, community-acquired pneumonia, C-reactive protein, C-reactive protein-to-albumin ratio, mortality.

Toplum kökenli pnömonide mortaliteyi öngören bir belirteç olarak C-reaktif protein/albumin oranı

Abstract

Amaç: Bu çalışma, acil servise (AS) başvuran toplum kökenli pnömoni (TKP) tanısı almış hastalarda C-reaktif protein/albumin oranının (CAR) 30 günlük mortaliteyi öngörmedeki prognostik değerini değerlendirmeyi amaçlamaktadır.
Gereç ve Yöntemler: Bu retrospektif çalışma, 1 Ocak 2022 ile 1 Ocak 2024 tarihleri arasında üçüncü basamak bir hastanenin AS’ine başvuran ve TKP tanısı konulan 312 hastayı içermektedir. Demografik, klinik ve laboratuvar verileri, C-reaktif protein (CRP) ve albumin düzeyleri dahil olmak üzere toplanmıştır. CAR, CRP düzeyinin (mg/dL) albumin düzeyine (g/L) bölünmesiyle hesaplanmıştır. Birincil sonuç, 30 günlük mortalite olarak belirlenmiştir. CAR'ın prognostik performansı, ROC eğrisi (receiver operating characteristic) analizi kullanılarak değerlendirilmiştir.
Bulgular: Çalışmaya dahil edilen 312 hastanın 87’si (%27,9) 30 gün içinde hayatını kaybetmiştir. Hayatta kalamayan hastalar, sağ kalanlara kıyasla anlamlı derecede yüksek CAR değerlerine sahipti (1,18 ± 0,62'ye karşı 0,52 ± 0,25, p < 0,001). CAR, 30 günlük mortaliteyi öngörmede mükemmel ayırt edici güce sahipti (Eğri altındaki alan (AUC): 0,837, %95 GA: 0,791–0,876, p < 0,001). >0,77 eşik değeri kullanıldığında, CAR %75,9 duyarlılık ve %86,7 özgüllük gösterdi.Hayatta kalamayan hastalar ayrıca daha düşük sistolik ve diyastolik kan basıncına, oksijen satürasyonuna ve albumin düzeylerine sahipken, daha yüksek CRP düzeyleri ve solunum hızları gösterdi. Ayrıca, inme ve konjestif kalp yetmezliği gibi komorbiditeler hayatta kalamayan hastalarda sağ kalanlara kıyasla daha yaygındı.
Sonuç: C-reaktif protein/albumin oranı (CAR), TKP hastalarında 30 günlük mortaliteyi öngörmede güvenilir bir prognostik belirteçtir. Kolay hesaplanabilirliği ve güçlü ayırt edici gücü nedeniyle, CAR risk sınıflandırması ve klinik karar verme süreçlerinde değerli bir araç olabilir. Bu bulguların farklı popülasyonlarda doğrulanması için prospektif çalışmalara ihtiyaç duyulmaktadır.

Keywords

Albumin, community-acquired pneumonia, C-reactive protein, C-reactive protein-to-albumin ratio, mortality.

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