Screening patients to assess renal function before administering gadolinium chelates: Assessment of the Choyke questionnaire

OBJECTIVE. The purpose of our study was to determine the efficacy of using the Choyke questionnaire to stratify the potential risk for nephrogenic systemic fibrosis (NSF) before a gadolinium-enhanced MRI examination and to compare the economic impact of such an approach with universal blood sampling before gadolinium-enhanced MRI. MATERIALS AND METHODS. We retrospectively reviewed the records of 1,086 consecutive outpatients referred for gadolinium-enhanced MRI. For inclusion, patients were required to have an estimated glomerular filtration rate (eGFR) result within 30 days before gadolinium-enhanced MRI and a completed Choyke questionnaire, first when the order was placed and again at the point of service. Questionnaire results were dichotomized into "No" (all no responses in both questionnaires) or "Yes" (one or more yes responses in either questionnaire) response groups for comparison with the corresponding eGFR. An economic impact assessment for using the questionnaire to identify "at risk" patients was performed using a decision-analytic model. RESULTS. Entry criteria were met in 665 of 1,086 (61.2%) patients. Zero patients in the No (n = 287) and seven in the Yes (1.9%) group (n = 378) had an eGFR of less than 30 mL/min/1.73 m². Using the 100% sensitivity achieved in identifying higher risk patients (seven patients; 95% CI, 59-100%), the questionnaire could save $4.52 per patient. At the lower boundary of the 95% CI for sensitivity, the savings incurred would come at the expense of administering gadolinium to 0.4% of patients with an eGFR less than 30 mL/min/1.73 m². CONCLUSION. The Choyke questionnaire effectively stratifies patients for NSF risk before gadolinium-enhanced MRI, offering potential cost savings and streamlined care.