Though 28-49% of severe sepsis hospitalizations have been described to be culture negative, there is very limited data on epidemiology and outcomes of those with culture negative severe sepsis (CNSS). The objectives of this study were to investigate the proportion and trends of CNSS, and its association with mortality.
Using Nationwide Inpatient Sample database from 2000-2010 we identified adults hospitalized with severe sepsis. Those without any specific organism codes were identified as with CNSS. We examined the proportion of CNSS hospitalizations and rates of mortality associated with it. We also assessed the independent effect of CNSS on mortality.
Of 6,843,279 admissions with severe sepsis 3,226,406 (47.1% ) were culture negative. The age-adjusted proportion of CNSS has increased from 33.9% in 2000 to 43.5% in 2010 (p<0.001). Those with CNSS had more co-morbidities, acute organ dysfunctions (respiratory, cardiac, hepatic and renal) and in-hospital mortality (34.6% vs. 22.7%; p<0.001) though acute kidney injury requiring dialysis is less (5.3% vs. 6.1%; p<0.001). CNSS was an independent predictor of mortality in those with severe sepsis (OR 1.75; 95% CI: 1.72-1.77).
CNSS among hospitalized patients is common, and its proportion is on the rise. CNSS is associated with greater acute organ dysfunctions and mortality. Being culture negative is an independent predictor of death.