Analysis of risk factors in elderly patients with purple urine bag syndrome: A retrospective analysis in a medical center in northern Taiwan

Abstract

Background: Purple urine bag syndrome (PUBS), an uncommon phenomenon that turns urine tubes or bags purple or blue, can be encountered in long-term-care facilities. A thorough literature review shows that East Asia has a high incidence of PUBS. It is important to recognize the clinical features and risk factors of this phenomenon. The aim of this study is to explore the characteristics of patients with PUBS and correlate the onset of PUBS symptoms with risk factors. Materials and Methods: We reported nine cases of clinically confirmed PUBS between January 2009 and June 2013. Pertinent clinical information was collected, including age, feeding type, renal function, type of Foley catheter, urine analysis, and bacteriological data. Results: All of patients with PUBS presented with stable vital signs without evidence of clinical infection, such as fever or chills. The mean age of the patients was 86.6 ± 10.1 years, with a preponderance of females (77%). Five PUBS patients (55%) had a history of chronic renal insufficiency. Six patients (66%) had constipation. A logistic regression univariate analysis demonstrated a statistically significant urine pH in patients with PUBS [odds ratio (OR), 3.078; P = 0.036]. Risk factors, such as gender, were found to be significant using logistic regression multivariate analysis (OR, 0.031; P = 0.021). During the follow-up, all of the patients had Foley catheters re-inserted, and all of the patients received health education. Conclusion: The incidence of PUBS in the elderly population is associated with asymptomatic bacteriuria, urine pH, and gender but not renal function, type of feeding, or type of Foley catheter used. To understand PUBS and maintain urological hygiene, it is important to educate families and health care workers about PUBS and to recognize that PUBS is not regarded as a symptom of severe disease.