Platelet/leukocyte ratio as a predictor of mortality in patients with sepsis

Background

The platelet count is an established index in the evaluation of severity in patients with sepsis, and therefore is a component of the SOFA score [1]. Furthermore, the alterations in leukocyte count are also used in the definition of SIRS. The present study aims to evaluate the accuracy of the platelet/leukocyte ratio (P/L) as a predictor of mortality in septic patients.

Materials and methods

Retrospective cohort study conducted on patients admitted to the ICU of Hospital Anchieta, Brasília, DF, Brazil, during 3 years. The patients with sepsis were divided according to P/L as follows: P/L ≥8 group (HPL) or P/L <8 (LPL). The primary outcome was mortality at 4 and 28 days. Accuracy of P/L to predict ICU mortality was measured with the area under the receiver operating characteristic curve.

Results

In the present study, 195 patients were enrolled, 41% (n = 80) with septic shock. Their mean age was 62.8 ± 21.6 years, SAPS 3 was 62.1 ± 15.0, APACHE II was 20.6 ± 8.6, and length of stay in the ICU was 9 ± 11 days. Mortality at 4 days was 10.8% (n = 21) and at 28 days was 12.3% (n = 24). The groups P/L <8 and P/L ≥8 did not present differences regarding age (59 ± 20 vs. 65 ± 22, P = 0.07) and APACHE II (22 ± 9 vs. 20 ± 9, P = 0.19). The LPL group had higher SAPS3 (68 ± 18 vs. 59 ± 13, P = 0.00). The LPL was significantly associated with mortality in 4 days (18% vs. 7%, P = 0.02) and 28 days (19% vs. 9%, P = 0.03). The area under the ROC curve of P/L for mortality at day 4 was 0.628 (95% CI 0.498 to 0.757) and at day 28 was 0.613 (95% CI 0.489 to 0.736).

Conclusions

P/L <8 at admission was associated with higher mortality in 4 and 28 days in patients with sepsis.