Albumin may prove a predictor for pneumonia outcomes

By Piriya Mahendra, medwireNews Reporter

Researchers say that assessing serum albumin levels within 24 hours of admission could be a good prognostic marker of community-acquired pneumonia (CAP).

Physicians should consider albumin levels when evaluating the severity of illness in patients with CAP, say Diego Viasus (Hospital Universitari de Bellvitge-IDIBELL, Barcelona, Spain) and co-authors in the Journal of Infection.

The research shows that reduced albumin levels could highlight CAP patients most at risk for adverse outcomes. Therefore, investigating whether treatment of CAP-associated hypoalbuminemia would improve clinical outcomes merits further investigation, explain Viasus and team.

The median value of serum albumin in 3463 hospitalized CAP patients (mean age 65.9 years) was 31 g/L. Hypoalbuminemia (albumin <30 g/L) was present in 1307 (37.7%) patients. Overall, 53 (1.5%) patients had a serum albumin level of less than 20 g/L, 336 (9.7%) between 20 and 24.9 g/L, and 918 (26.5%) between 25 and 29.9 g/L.

In addition, 1237 (35.7%) patients had a serum albumin level between 30 and 34.9 g/L, 762 (22%) between 35 and 39.9 g/L, and 157 (4.5%) over 40 g/L.

The researchers found that the lower the level of serum albumin at hospital admission, the higher the risk for complications, including bacteremia, septic shock, empyema, acute cardiac events, or nosocomial infections. Indeed, 69.8% of individuals with an albumin level of less than 20 g/L experienced these complications, compared with only 12.7% of those with an albumin level of over 40 g/L.

Furthermore, low albumin levels were significantly associated with a prolonged time to reach clinical stability (above the median of 4 days), prolonged hospital stay (above the median of 8 days), intensive care unit (ICU) admission, the need for mechanical ventilation, and 30-day mortality.

After adjusting for potential confounders in multivariate analysis, each 5-g/L reduction in serum albumin levels at admission was associated with a 1.63-fold increased risk for ICU admission and a 2.11-fold increased risk for 30-day mortality.

Receiver-operating characteristic curve analysis showed that hypoalbuminemia was a significant predictor for 30-day mortality and accurately identified patients with a high risk for complications according to the Pneumonia Severity Index and CURB-65 (confusion, urea level, respiratory rate, blood pressure, and age >64 years).

"The inclusion of hypoalbuminemia significantly improved the prognostic performance of CAP prediction rules," explain the authors.

They say that serum albumin may exert a protective effect on outcomes in CAP patients by maintaining osmotic pressure and microvascular integrity, transporting hormones such as cortisol and thyroxine, modulating acid-base balance, and inducing antioxidant and anti-apoptotic effects.

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