PURPOSE: Many severity scores have been studied to determine mortality risk in patients with pneumonia, of which one of the most commonly used is the CURB-65 score. Hyponatremia has been shown to be independently associated with mortality in such patients. We aimed to examine the value of CURB-65 score in patients with dysnatremia.
METHODS: We performed a retrospective study of patients admitted to our ICU with a diagnosis of pneumonia between 07/2003 and 12/2009, entered in the Project Impact database. Inclusion criteria were age > 17 years and admission through emergency department. We recorded demographic data, lowest serum sodium in first 24 hours, the presence of components of the CURB-65 score, and mortality. We analyzed the data using Chi-square test and recursive partitioning analysis (RPA).
RESULTS: Of 406 patients identified, 357 had complete data. The mean values were age 63 years [51-75], sodium 137 mEq/dL [134-140], and CURB-65 score 2 [1-3]. 94 patients (26.3%) died. Using the RPA, we found that sodium values of < 135 and >145 improved homogeneity of samples. These patients were categorized as dysnatremic (DY). There were 179 patients with DY (50%): 96 with Sodium < 135, 83 with Sodium >145. A high CURB-65 (HC-65) score (>2) was associated with increased mortality (OR 1.9 [1.2-3]) (p = 0.014). DY alone was not significantly associated with mortality (p=0.118). The presence of HC-65 and DY together were more likely than either alone to be associated with increased mortality (OR 2.2 [1.3-3.8], p = 0.004).
CONCLUSION: Presence of dysnatremia and high CURB-65 score is associated with higher mortality than either alone. Mechanisms for these findings are uncertain, but may include increased ADH secretion and hyponatremia in hypovolemic patients. Hypernatremia may be a marker for subset of high-risk patients presenting with significant free water deficits. A new severity score for patients with pneumonia, incorporating dysnatremia, should be designed and validated in prospective clinical trials.
CLINICAL IMPLICATIONS: Presence of dysnatremia and high CURB-65 score in pneumonia is associated with higher mortality than either alone.
DISCLOSURE: Ankur Kalra, No Financial Disclosure Information; No Product/Research Disclosure Information