Category: Clinical Stones: Medical Management
Introduction & Objective :
Increased fluid intake has been shown as the single most effective dietary change to decrease stone events. However, patient compliance with this recommendation is unknown. Twenty-four hour (24h) urine collections often represent patient’s best efforts at increased hydration due to the Hawthorne effect. We assessed compliance rates and demographic and clinical variables associated with 24h urine volume (UV) in patients with urolithiasis following dietary counseling.
Patients with a history of stone formation and sequential (2+) 24h urine collections were retrospectively identified. Inadequate collections with 24-hour urine creatinine under 600 mg/day and >20% variation from previous collections were excluded. All patients received dietary counseling, including increasing fluid intake achieve a goal urine volume of >2L/day. The total urine volume was assessed via 24h urine collection to assess compliance. Multivariable logistic regression modeling was used to identify independent predictors of patient compliance.
A total of 2,759 24-hour urines were analyzed in 573 patients. The median baseline urine volume was 1.7 L (IQR 1.3 – 2.3 L) and only 207 (36.1%) 24h urines reported a urine volume >2L and 118 (20.6%) of 24h urines reported a urine volume >2.5L. The compliance rate of obtaining urine volume of >2L was 52.0% and 32.5% for >2.5L at median follow up 351 (IQR 194-414) days from prior collection. 46.8% of patients had a decrease in urine volume at follow up. Only 11% of collections had an increase of 1L. On multivariate analysis, thiazide use (p=0.004) and bowel disease (p=0.049) were associated with greater odds of compliance with urine volume >2L. DM (p=0.003) and time between collections (p2L urine volumes. Age, gender, BMI, and summer collection time did not correlate with compliance.
24-hour urine collection compliance with recommendations for increased fluid intake remains low and compliance estimates are likely lower on a regular basis. Patients with diabetes or long time between collections were predictive of the lowest compliance. Patients at highest risk can be targeted for additional education or interventions to increase fluid intake to prevent future stone events.
Sara Best– Associate Professor, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
Kimberly Maciolek– Madison, Wisconsin
Kristina Penniston– Senior Scientist, University of Wisconsin School of Medicine and Public Health, Department of Urology, Madison, Wisconsin
University of Wisconsin School of Medicine and Public Health
University of Wisconsin School of Medicine and Public Health, Department of Urology
Kristina Penniston is a scientist and registered dietitian nutritionist in Madison, Wisconsin. Dr. Penniston earned her PhD in nutritional science from the University of Wisconsin-Madison. She completed a dietetic internship at the University of Wisconsin Hospital and Clinics and is a certified dietitian member and fellow of the Academy of Nutrition and Dietetics. Dr. Penniston has provided clinical nutrition services to patients with kidney stones and other urologic diseases, such as urologic cancer and benign urologic conditions, for 20 years. Dr. Penniston's research in the Department of Urology at the University of Wisconsin School of Medicine and Public Health focuses on prevention of kidney stones. Specifically, her research aims to develop and test dietary interventions that prevent or ameliorate recurrent stones; promote patients' self-efficacy in managing their stone disease; and understand and improve patients’ health-related quality of life. Dr. Penniston has developed a porcine model of dietary-induced calcium oxalate urolithiasis as a platform for studying dietary influences on stone formation. She also helped to develop the Wisconsin Stone Quality of Life questionnaire, a stone-specific instrument to assess patients' health-related quality of life. Dr. Penniston is a member of the American Urological Association and is a former research scholar (2008-2010). She has been a member of the Research on Calculus Kinetics (ROCK) Society since 2008 and was elected in 2018 as secretary/treasurer. Dr. Penniston publishes regularly in urologic and nutrition journals.