Trends in US hospital stays for Streptococcus pneumoniae-associated hemolytic uremic syndrome

Abstract

Background: Hemolytic uremic syndrome (HUS) is usually associated with diarrheal illness but can also occur in children with Streptococcus pneumoniae infection (SpHUS), particularly those with complicated pneumonia. Based on recent reports that hospital discharges for complicated pneumococcal pneumonia are increasing in US children, we studied whether discharges for SpHUS might also be increasing.

Methods: We used the Kids' Inpatient Database samples from 1997, 2000, 2003, 2006 and 2009 to estimate trends in US hospital discharges of children (0-18 years) for whom diagnosis codes indicated invasive pneumococcal disease, HUS, or both (SpHUS). Univariate and multivariate analyses were based on 2009 discharges.

Results: During the 5 study years, annual numbers of US hospital discharges for SpHUS approximately doubled (P = 0.025 for linear trend) and cumulatively totaled an estimated 211 discharges. In 2009, SpHUS accounted for 4.6% (95% confidence interval [CI]: 3.0%-6.7%) of HUS discharges, 0.7% (95% CI: 0.5%-1.0%) of invasive pneumococcal disease discharges and 3.0% (95% CI: 2.0%-3.9%) of discharges for complicated pneumococcal pneumonia. Discharges for SpHUS were more likely than those for other invasive pneumococcal disease to occur in children <3 years of age and to incur longer length of stay and greater hospital charges. SpHUS was independently associated with pneumococcal sepsis/bacteremia (age-adjusted odds ratio 3.8; 95% CI: 1.9-7.8) and complicated pneumonia (odds ratio 9.2; 95% CI: 4.1-20.7).

Conclusions: SpHUS is an uncommon but severe illness that primarily affects young children and is strongly associated with complicated pneumococcal pneumonia. US hospital stays for SpHUS appear to be increasing along with those for complicated pneumococcal pneumonia.