Trends in infection-related hospital admissions and impact of length of time on dialysis among patients on long-term dialysis: a retrospective cohort study

BACKGROUND: After cardiovascular disease, infection is the second leading reason for admission to hospital among patients receiving long-term dialysis. We examined whether duration of dialysis treatment influences the rate of infection-related admission to hospital. METHODS: Using provincial administrative databases for Quebec, we built a retrospective cohort of all adults receiving long-term dialysis (hemodialysis or peritoneal dialysis) between 2001 and 2007. We evaluated rates of infection-related admission to hospital according to length of time on dialysis. RESULTS: A cohort of 9822 patients (mean age 66.3 [standard deviation ± 14.7] yr; 39.7% female) were followed for a median of 2.1 (range 1.0-3.9) years. Between 2001 and 2007, infection-related hospital admissions remained stable (from 0.20 to 0.19 per person-year; p = 0.7). All-cause hospital admission rates decreased by 22.9% (from 1.53 to 1.18 per person-year; p < 0.001), and cardiovascular-related admission rates decreased by 46.7% (from 0.45 to 0.24 per person-year; p < 0.001). The rate of infection-related admission remained stable with increasing time on dialysis (p = 0.1); however, both all-cause and cardiovascular-related admission rates decreased with length of time on dialysis (p < 0.001). Standardization of hospital admission rates by age, sex or length of time on dialysis did not change trends. INTERPRETATION: We found a stable rate of infection-related hospital admission between 2001 and 2007 among patients on long-term dialysis, independent of age, sex and length of time on dialysis. A decrease in all-cause and cardiovascular-related admission rates during the same period meant that the proportion of admissions related to infection increased. Because admissions to hospital are potentially preventable, understanding the epidemiology of infection-related admissions may inform future studies on prevention of this serious outcome.