Severe sepsis in the UK and the case volume-outcome association

The association between case volume and outcome in healthcare was first described more than 30 years ago.1 Since then, multiple studies have confirmed that for many high risk surgical conditions, larger hospital case loads are associated with better patient outcomes.2 More recently, researchers have shown volume-outcome associations for high risk medical conditions as well, including mechanical ventilation for acute respiratory failure3 and severe sepsis,4 5 6 the critical illness syndrome characterised by infection, inflammation, and systemic organ failure.

However, new data suggest that volume-outcome relations in intensive care are not universal. In a linked study (doi:10.1136/bmj.e3394), Shahin and colleagues report equivalent outcomes for patients with severe sepsis who were treated in low volume and high volume critical care units in the United Kingdom.7 Similar outcomes were found among patients who needed mechanical ventilation and patients with the highest severity of illness, subgroups of patients for whom a volume-outcome association is most likely to …