Validation of the Pyruvate Kinase Deficiency Diary (PKDD): A Patient-Reported Outcome Measure for Pyruvate Kinase (PK) Deficiency

Introduction: Pyruvate kinase (PK) deficiency is a rare hereditary disorder characterized by chronic hemolytic anemia and long-term complications such as iron overload, osteoporosis, and pulmonary hypertension. There are no patient-reported outcome (PRO) instruments that are specific for this condition. The PK Deficiency Diary (PKDD), a disease-specific PRO, was designed as an evening diary to assess signs and symptoms for patients with PK deficiency. The seven-item instrument assesses tiredness, jaundice, bone pain, shortness of breath, and energy levels. Six of the seven items employ a numeric rating scale (NRS) ranging from 0-10 and one item uses a 5-point verbal descriptor scale. The instrument underwent psychometric validation using blinded data from the eighty patients participating in the ACTIVATE trial, a randomized, multicenter, double-blind, phase 3 trial of mitapivat, an allosteric activator of PK, in non-regularly transfused adults with PK deficiency (NCT03548220).