Purpose: To assess the psychometric properties of the disease-specific Hypoparathyroidism Symptom Diary (HypoPT-SD) patient-reported outcome (PRO) tool, which consists of a 7-item symptom subscale, a 4-item impact subscale, a single item for anxiety, and a single item for sadness or depression, using data from the BALANCE randomized, placebo-controlled Phase 3b/4 study (NCT03324880). Methods: Eligible patients had symptomatic hypoparathyroidism (HypoPT) at baseline and were aged 18– 85 years (inclusive). Patients received recombinant human parathyroid hormone (1– 84) or placebo. The HypoPT-SD was filled in daily; data recorded at baseline and Weeks 4, 12, and 26 (end of treatment EOT) were included in this analysis. Inter-item and item–total correlations were used to assess HypoPT-SD structure; Cronbach’s coefficient α was used to analyze the internal consistency and reliability, and intraclass correlations were used to measure test–retest reliability. Construct validity was determined using correlational analyses between HypoPT-SD scores and scores from other conceptually similar PRO tools. Ability to detect change was assessed and thresholds for meaningful within-patient change were established. Results: The psychometric analysis population (N=93) was predominantly female (88.2%) and white (96.8%), with a mean age of 48.5 years. Inter-item correlations ranged from 0.35 to 0.85 at baseline and from 0.49 to 0.93 at EOT. Item–total correlations ranged from 0.57 to 0.83 at baseline and from 0.69 to 0.88 at EOT. Cronbach’s α values at baseline were 0.90 (symptom subscale) and 0.88 (impact subscale). Intraclass correlation coefficients for both subscales in stable patients exceeded 0.70. Significant cross-sectional correlations were observed with most of the conceptually linked PRO tools analyzed, and HypoPT-SD scores were responsive to change. Potential changes of 1.5 (symptom subscale) and 0.8 (impact subscale) were determined as meaningful change thresholds for within-patient improvements. Conclusion: The HypoPT-SD is a reliable measure of key symptoms and impacts of HypoPT. Keywords: hypoparathyroidism, patient-reported outcomes, psychometric, quality of life
Wang et al. (Sun,) studied this question.