Healthcare-associated infection among residents of long-term care facilities: a cohort and nested case-control study.

Knowledge of infection control measures in nursing homes is limited. This study aimed to assess the incidence of, and potential risk factors for, healthcare-associated infection in long-term care facilities in Norway. Incidence of healthcare-associated infection was recorded prospectively in six long-term care facilities located in two major cities in Norway between 1 October 2004 and 31 March 2005. For each resident with an infection we aimed for two controls in a nested case-control study to identify potential risk factors. Incidence of infection was 5.2 per 1000 resident-days. Urinary and lower respiratory tract infections were the most common. Patients confined to their beds [odds ratio (OR=2.7)], who stayed <28 days (OR=1.5), had chronic heart disease (OR=1.3), urinary incontinence (OR=1.5), an indwelling urinary catheter (OR=2.0) or skin ulcers (OR=1.8) were shown to have a greater risk for infection. Age, sex and accommodated in a two- versus single-bed room were not significant factors. Incidence of infection in nursing homes in Norway is within the range reported from other countries. This study identified several important risk factors for healthcare-associated infection. There is a need to prevent infection by implementing infection control programmes including surveillance in long-term care facilities.