High-Density Lipoprotein Predicts Intrahospital Mortality in Influenza

<b>Background:</b> Although it is known that high-density lipoprotein (HDL) exerts important anti-inflammatory effects and that low HDL plasma concentrations represent a negative prognostic marker in bacterial infections and sepsis, not much is known about possible implications of HDL in acute viral infections such as influenza. <b>Methods:</b> We performed a retrospective, single-centre analysis of influenza patients hospitalised during the 2018/19 and 2019/20 influenza seasons and analysed the impact of HDL concentrations on inflammation and mortality. <b>Results</b>: 199 influenza patients (173 male patients) were admitted during the 2018/19 and 2019/20 influenza seasons with a mortality rate of 4.5%. HDL was significantly lower in deceased patients (median HDL 21 (IQR 19-25) vs. 35 (IQR 28-44) mg/dL; <i>p</i> = 0.005). Low HDL correlated with increased inflammation and HDL was an independent negative predictor regarding mortality after correction for age and the number of comorbidities both overall (OR = 0.890; <i>p</i> = 0.008) and in male patients only (OR = 0.891; <i>p</i> = 0.009). <b>Conclusions:</b> Low HDL upon hospital admission is associated with increased inflammation and is an independent predictor for increased mortality in male patients with influenza A.