2009 influenza A infection and acute kidney injury: incidence, risk factors, and complications

Abstract

Background: 2009 influenza A has spread globally. Respiratory complications and renal failure have been the leading causes for hospitalization and critical illness. We describe the risk factors and complications of acute kidney injury (AKI) in patients with influenza A.

Methods: Observational study of adult patients tested for influenza A. Outcome measures include AKI [AKI Network (AKIN) criteria] and mortality.

Results: From August through December 2009, 17% (89/515) of hospitalized subjects were tested positive for influenza A. The incidence of AKI (AKIN(I-III)) was 42% (37/89) in subjects with influenza A; the majority (65%, 24/37) of whom were critically ill. Risk factors for AKI included obesity, chronic kidney disease (CKD), and elevated creatine kinase. Positive influenza A status was associated with lower AKI (AKIN(I-III)) risk compared to seronegative subjects (OR 0.5, CI 0.3-0.9). Mortality in patients with influenza A and AKI requiring dialysis was 50%.

Conclusions: Obesity, CKD, and elevated creatine kinase are associated with AKI in patients with influenza A. Influenza A is not independently associated with higher incidence of AKI in hospitalized patients. AKI is an independent risk factor for mortality in patients with influenza A.