Infection is an important cause of hospitalization and death in patients receiving dialysis. Few studies have examined the full range of infections experienced by dialysis patients. The purpose of this study was to examine the types, rates and risk factors for infection among older persons starting dialysis.
Retrospective observational cohort study.
Setting and Participants
The cohort was assembled from the United States Renal Data System and included patients aged 65 to 100 years who initiated dialysis between 1/1/00 and 12/31/02. Exclusions included prior kidney transplant, unknown dialysis modality, or death, loss to follow-up, or transplant during the first 90 days of dialysis. Patients were followed until death, transplant, or study end 12/31/04.
Baseline demographics, co-morbidities, serum albumin and hemoglobin.
Outcomes and Measurements
Infection-related hospitalizations were ascertained using discharge ICD-9-CM codes. Hospitalization rates were calculated for each type of infection. The Wei-Lin-Weissfeld Model was used to examine risk factors for up to 4 infection-related events.
119,858 patients were included, 7,401 of whom were on peritoneal dialysis. During a median follow-up of 1.9 years, infection-related diagnoses were observed in approximately 35% of all hospitalizations. Approximately 50% of patients had at least one infection-related hospitalization. Rates (per 100 person-years) of pulmonary, soft tissue, and genitourinary infections ranged from 8.3 to 10.3 in patients on peritoneal dialysis and 10.2 to 15.3 in patients on hemodialysis. Risk factors for infection included older age, female sex, diabetes, heart failure, pulmonary disease, and low serum albumin.
Use of ICD-9-CM codes, reliance on Medicare claims to capture hospitalizations, use of the Medical Evidence Form to ascertain co-morbidities, absence of data on dialysis access.
Infection-related hospitalization is frequent in older patients on dialysis. A broad range of infections – many unrelated to dialysis access – result in hospitalization in this population.