Prevalence and characteristics of nursing home-acquired infections in the aged.

Objectives: This study provides estimates of the prevalence of infections in all patients from a representative sample of 53 Maryland nursing homes; identifies risk factors for these infections; and describes diagnostic procedures carried out. Methods: The records of 4,259 patients in a stratified random sample of 53 Maryland nursing homes were reviewed for diagnostic procedures, medical, functional, and behavioral status. Infections were identified by signs, symptoms, and laboratory findings. Results: Study patients were characteristic of aged patients in US nursing homes. The prevalence of infections actually acquired in the nursing home (80% of all infections) was 4.4%. Multivariate analysis revealed that skin infections (35% of nursing home-acquired infections) were associated with skin ulcers and inversely with urine incontinence. Fevers of uncertain source (13%) were associated with bladder catheters. Symptomatic urinary infections (12%) and lower respiratory infections (12%) were associated with bedfast status, and the latter with tracheostomy and lung disease. Skin ulcers, urethral catheters, and bedfast status were markers for nursing home-acquired infection. The prevalence of infection in patients with all three markers was 32%; in patients with none, 2%. Fewer than a quarter of the four most common nursing home-acquired infections received an evaluation which met minimal diagnostic criteria established by a panel of infectious disease specialists and geriatricians. Patients with dementia, those in large homes (> 150 beds), and those in urban homes were less likely to be evaluated in a manner meeting these criteria. Conclusions: Use of three characteristics (ie skin ulcers, urethral catheters, bedfast status) to identify patients at risk for nursing home-acquired infections may allow targeted infection surveillance and prevention programs. In addition, nursing home-acquired infections are not evaluated uniformly across patients and facilities, suggesting the need to establish, through further study, guidelines for such evaluations.