Attributable rates of infections due to Indwelling Device use in Skilled Nursing Facilities

Background: Indwelling devices such as urinary catheters and feeding tubes increase the risk of infections. 

Objective: To estimate the proportion of incident infections attributable to indwelling devices in skilled nursing facility (SNF) residents.

Methods: We enrolled residents with indwelling devices and their randomly selected controls from 7 SNFs in SE MI.  Monthly data on infections were obtained by research staff. Infections were defined by clinical notes documenting an infection followed by prescription of an antibiotic to treat that infection. We calculated attributable risk to measure the excess rate of infections in those with indwelling devices compared to those without a device. We also calculated attributable proportion by calculating the proportion of infections among the exposed group that could be prevented by removing indwelling devices.

Results: 177 residents were enrolled; 88 in device group & 89 in control group with a follow-up of 912 person-months (267 person-months in device group, 645 person-months in control group). A total of 187 infections were detected with an incidence rate 78/100 person-mo in device-group and 41/100 person-mo in control group (p < 0.001) with an incidence rate ratio of 1.89 (95% CI: 1.5,2.4).  The attributable risk or excess infections among residents with indwelling devices was 37 per 100 person-mo. The attributable proportion was 47% (95% CI: 31,58).

Conclusions: Our data quantifies the risk of infections in SNF residents with indwelling devices and shows that approximately half of all infections in patients with indwelling devices can be eliminated if they did not use those devices. Our data emphasizes the need to reduce the use of indwelling devices in SNF residents.