Journal Article

Psychometric evaluation of the Indolent Systemic Mastocytosis Symptom Assessment Form (ISM-SAF©) and determination of a threshold score for moderate symptoms

Boral, Anthony L., Severson, Kas, Mar, Brenton, Shields, Alan L., Green, Tanya, Akin, Cem, Taylor, Fiona, Padilla, Brad, Siebenhaar, Frank, Lamoureux, Roger E.

2023

Overview

Background The Indolent Systemic Mastocytosis Symptom Assessment Form (ISM-SAF) (©Blueprint Medicines Corporation), a 12-item daily diary that assesses 11 signs and symptoms of indolent systemic mastocytosis (ISM) and smoldering systemic mastocytosis (SSM), was psychometrically evaluated among patients with ISM. Additionally, thresholds of the ISM-SAF total symptom score (TSS) to distinguish patients with moderate to severe symptoms from those with mild symptoms were evaluated. Methods The ISM-SAF was completed daily as an electronic diary in a prospective, observational study utilizing an online survey of patients with ISM in the United States. Descriptive statistics, psychometric analyses, and analyses to estimate ISM-SAF TSS clinical cutoff values were conducted. Results A total of 103 patients (81.6% female; mean age = 50.2 [± 12.6]) with a self-reported diagnosis of ISM or SSM (58 of whom also had a medically documented diagnosis) contributed to the analyses. Psychometric analysis supported the trustworthiness of the biweekly TSS, which was reliable ( α  > 0.8, ICC > 0.9), construct-valid, and able to distinguish among clinically distinct groups as specified by the Patient Global Impression of Severity, 12-item Short-Form Health Survey, and Mastocytosis Quality of Life Questionnaire ( p  < 0.01). A biweekly ISM-SAF TSS from 21 to 28 begins to distinguish the moderately to severely symptomatic ISM/SSM patients from mildly symptomatic patients. Conclusion The biweekly TSS of ISM-SAF was reliable, construct-valid, and able to distinguish among clinically distinct groups. A cut-off value of 28 is a conservative threshold that can be used for screening purposes in future clinical studies to identify patients with at least a moderate severity of ISM symptoms.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Analysis / Care and treatment / Diagnosis / Diarrhea / Documentation / FDA approval / Female / Gene mutations / Genetic aspects / Haematology / Health aspects / Human Genetics / Humans / Indolent systemic mastocytosis / Instrument development / Male / Mast cell disease / Mastocytosis / Mastocytosis, Systemic - diagnosis / Medical research / Medicine / Medicine & Public Health / Medicine, Experimental / Middle Aged / Patient-reported outcomes / Patients / Pharmacology/Toxicology / Prospective Studies / Psychometric evaluation / Psychometrics / Qualitative research / Quality of Life / Quantitative psychology / Questionnaires / Rare diseases / Self report / Statistical analysis / Surveys / Symptom Assessment / Validity