Consequences of MRSA carriage in nursing home residents

A prospective cohort study with 1 year follow-up evaluated the relation between MRSA carriage and mortality, likelihood of hospitalization and functional status in residents of a nursing home for the elderly. Included were all 447 residents living in the home in early June 1994. From all patients, swabs were taken from nose, throat and perineum. Additional swabs (sputum, urine or wounds) were taken when indicated. The relative risk (RR) of dying within 6 months in MRSA carriers compared to non-carriers was 2.29 (95% CI = 1.04-5.04). This RR remained stable (1.57-2.40) after adjustment for co-variables using Mantel-Haenszel stratified analysis. After I year, the RR was reduced to 1.30 (95% CI = 0.65-2.58). Univariate survival analysis confirmed a difference in survival between carriers and non-carriers after 6 months (log-rank P = 0.04) and no difference after 1 year. Cox regression analysis resulted in a hazard ratio for dying within 6 months of 1.73 (95% CI = 0.72-4.17). No relation was found between carriage and either likelihood of hospitalization or indicators of functional status. These results are compatible with a possible relation between 6 months mortality and MRSA carriage in nursing home patients. It calls for a large scale, multicentre cohort study in order to either confirm or refute these findings.