High Mean Platelet Volume Associates with In-Hospital Mortality in Severe Pneumonia Patients
Jieru Chen, Yihao Li, Yingsi Zeng, Yu Tian, Yueqiang Wen, Zebin Wang
Abstract
Background . Although mean platelet volume (MPV) appears to be associated with poor outcome of pneumonia, the relationship between MPV and in-hospital mortality is unclear in severe pneumonia (SP) patients. Methods . In this retrospective cohort study, 115 SP patients from June 1st, 2016, to September 29th, 2019, were included and divided into two groups. The primary outcome was in-hospital mortality. The receiver operating characteristic (ROC) curve was performed to assess the predictive ability for in-hospital mortality. Kaplan-Meier cumulative incidence curves were applied to observe the incidence of mortality. Multivariable Cox regression analyses were used to evaluate the hazard ratios (HRs). Besides, a formal test for interaction was investigated to analyze the relationship between MPV and sex. Results . During the course of hospitalization, 63 cases of mortality were recorded. ROC analysis suggested that MPV had a modest power for predicting in-hospital mortality (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mtext>AUC</mml:mtext><mml:mo>=</mml:mo><mml:mn>0.723</mml:mn></mml:math>, 95% CI: 0.628-0.818, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mi>P</mml:mi><mml:mo><</mml:mo><mml:mn>0.001</mml:mn></mml:math>). Yet the cutoff value of MPV was 10.5 (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mtext>sensitivity</mml:mtext><mml:mo>=</mml:mo><mml:mn>73.02</mml:mn></mml:math>%; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mtext>specificity</mml:mtext><mml:mo>=</mml:mo><mml:mn>73.08</mml:mn></mml:math>%). Compared to the low-MPV group, the high-MPV group had significantly increased in-hospital mortality (log-rank <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M5"><mml:mtext>test</mml:mtext><mml:mo>=</mml:mo><mml:mn>13.501</mml:mn></mml:math>, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M6"><mml:mi>P</mml:mi><mml:mo><</mml:mo><mml:mn>0.001</mml:mn></mml:math>), while the adjusted Cox model indicated that the high-MPV group was associated with an elevated risk of in-hospital mortality (HR: 2.267, 95% CI: 1.166-4.406, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M7"><mml:mi>P</mml:mi><mml:mo>=</mml:mo><mml:mn>0.016</mml:mn></mml:math>). Moreover, analyses of in-hospital mortality suggested a significant interaction between optimal MPV level and sex (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M8"><mml:mi>P</mml:mi><mml:mo>=</mml:mo><mml:mn>0.011</mml:mn></mml:math>). In a multivariate Cox model which included females only, a high MPV level was associated with increased risk of in-hospital mortality (HR: 11.387, 95% CI: 1.767-73.380, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M9"><mml:mi>P</mml:mi><mml:mo>=</mml:mo><mml:mn>0.011</mml:mn></mml:math>). Conclusion . High MPV level is an independent risk factor for in-hospital mortality in patients with SP.