Routine Laboratory Testing Every 4 Versus Every 6 Weeks for Patients on Maintenance Hemodialysis: A Quality Improvement Project

Abstract

Rationale & Objective: Few data exist revealing how the frequency of routine blood work for patients on maintenance hemodialysis therapy affects patient outcomes and the costs of care. Our objective was to determine the effect of changing the frequency of blood work from 4- to 6-week intervals on the achievement of anemia and chronic kidney disease–mineral and bone disorder (CKD-MBD) targets. Study Design: Retrospective interrupted time series from June 1, 2012, to December 31, 2015. Setting & Participants: Tertiary hospital in Ontario, Canada, that provides maintenance hemodialysis therapy to 350 to 400 adult patients. Quality Improvement Activities: Institution-wide switch of the interval for routine blood work from 4 to 6 weeks on March 24, 2014. Outcomes: Achievement of recommended hemoglobin and phosphate level targets. Cost savings attributable to a change in frequency of blood work for hemoglobin, ferritin, iron saturation, calcium, and phosphate comparing 252-day periods under each testing frequency condition. Analytical Approach: Statistical process control to analyze variation in the clinical outcomes. Results: The proportion of patients who achieved hemoglobin (10-12 g/dL) and phosphate (2.5-4.6 mg/dL) targets remained stable (average of 60% and 46%, respectively), with no measurements beyond 3 standard deviations from the mean. The hemodialysis unit mortality rate also remained stable (average of 2% per month). Reducing blood work frequency to every 6 weeks was associated with a saving of $85 per patient-year, corresponding to a program-wide savings of $35,000. Limitations: No case-mix adjustment due to use of aggregate hemodialysis unit data, and absence of data for hospitalizations and transfusions limiting assessment of the full cost of patient care. Conclusions: After switching the frequency of routine blood work from 4- to 6-week intervals, performance on anemia and CKD-MBD targets did not change and the reduction in blood work was associated with laboratory cost savings. Reducing the frequency of blood work may represent an opportunity for hemodialysis providers to devote greater efforts toward other care elements that better improve patient outcomes.