Friday, January 21, 2011

MRSA Body Count

MRSA on the Death Certificate: Questions about Accuracy

Surveillance for MRSA has hit the morgue. Investigators in Ireland published a manuscript on documentation of MRSA on death certificates. When reviewing 132 patients who had MRSA or MSSA isolated from blood cultures within 30 days of death, differences in death certificate documentation were noted. Fifteen (25.4%) of the 59 MRSA cases had MRSA documented on the death certificate while nine (12.2%) of the 74 patients with MSSA had MSSA documented on the death certificate. MRSA was more likely to be documented on the death certificate than MSSA (odds ratio: 2.46; 95% confidence interval: 1.01–6.01; P < 0.05). These findings suggest that inconsistencies exist in the way organisms are documented on death certificates and that there may be a bias to overemphasize MRSA on death certificates.

If death certificates to be used for surveillance of organism specific mortality, then methodology must be clear, definitions must be accurate (crude vs attributable mortality), and the process must be free of bias.

Most patients do not undergo autopsy and many death certificates, at least in the USA, are completed by fatigued interns, who likely do not review the case specifics in full prior to documenting the presumed cause if death. This will lead to documentation error and misclassification.

The morgue may not be the most meaningful place to track MRSA.