Impact of stroke-associated infection on long-term survival: a cohort study

Abstract

Background and objective: The effects of stroke-associated infection (SAI) on long-term survival are unclear. We performed a prospective evaluation to explore risk factors of SAI, and compared survival status over the 3 years following stroke onset between those who experienced SAI and those who did not.

Methods: Consecutive patients with acute stroke admitted to a stroke unit between April 2005 and December 2006 were invited to participate. We prospectively collected data on demographics, pathological and clinical stroke subtype, stroke severity, and neurological and functional consequences, and abstracted additional data on occurrence and timing of SAI in hospital from medical notes. Survival status 3 years after stroke onset was obtained.

Results: We recruited 413 acute stroke patients, 161 (39%) experienced SAI. After excluding patients with infection at onset, patients with intracerebral haemorrhage (p=0.014), dysphagia (p=0.003) and urinary incontinence/catheterisation (p=0.000) were at higher risk of infection after controlling for case mix. The risk of death in hospital was greater following an SAI (HR 3.56; 95% CI 1.94 to 6.53; p=0.000), as was risk of death calculated over the whole 3-year follow-up period among those acquiring SAI within 2 weeks of onset (HR 1.66; 95% CI 1.14 to 2.40; p=0.031).

Conclusions: SAIs have long-lasting effects on patient survival. This serves to emphasise the importance of immediate access to organised stroke unit care for people with acute stroke, with active physiological monitoring and protocols for early detection and treatment of SAIs.