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

Summary

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.

Introduction

Healthcare-associated infections are common and important causes of illness among elderly residents in long-term care facilities. Prevalence surveys from Norway have shown that at any given time, one in 17 residents (around 6%) had either urinary tract, lower respiratory tract, skin or surgical site infection.¹ Other countries have reported prevalences from 5 to 16%.2, 3, 4, 5, 6 In North America, incidence rates have varied between 1.8 and 13.5 infections per 1000 resident days.⁷

Over the last few years, increased attention has been given to infection control in long-term care facilities. It is clear that the magnitude of the infection problem is comparable to that in acute care hospitals. In addition, residents and staff move between long-term care facilities and hospitals, bringing with them nosocomial pathogens.⁸ The increasing problem of meticillin-resistant Staphylococcus aureus (MRSA) in long-term care facilities highlights the need for increased focus on infection prevention.9, 10

Long-term care facilities in Norway are freestanding, usually owned and run by the municipal authorities, and not part of acute hospitals. They provide 24 hrs nursing care and related medical services. While 14% of beds are special units for persons suffering from dementia, about 11% of beds are allocated for short-term stay only.¹¹ In 2003 there were 1000 long-term care facilities with a total capacity of 41 718 beds in Norway, twice as many as in 1984. Of those living in a long-term care facility, 77% were aged >80 years.12, 13, 14 Most residents have complex medical problems, which may further increase susceptibility to infection.

The main objectives of this study were to measure the incidence of healthcare-associated infection in long-term care facilities and to assess the risk factors in order to improve the knowledge base for infection control measures.