Are MRSA infections more costly?

How much extra cost, morbidity and mortality are attributable to antibiotic resistance?  The conventional wisdom is: “a lot”.  However, those most likely to develop serious infections with resistant pathogens are usually much sicker than those infected with susceptible bugs.  I’m not sure that our traditional ways of “adjusting” for these differences are adequate.  Nonetheless, the most extreme estimates of worse outcomes are always cited (including by me!).  Len Mermel’s group in Rhode Island have an interesting paper in this month’s issue of ICHE that points out how difficult it can be to adjust for differences in population characteristics when comparing cohorts infected with susceptible versus resistant pathogens.  They examined 182 patients with S. aureus bloodstream infection, comparing those with MRSA versus MSSA infections.  Using standard multivariable regression analysis, hospital costs and lengths of stay were higher for the MRSA cohort.  However, when they used a propensity scoring method, there were no differences noted in costs or lengths of hospital stay.