Patient-Reported Burden of Indolent Systemic Mastocytosis in a Managed Care Organization

Indolent systemic mastocytosis (ISM), the most frequent subtype of systemic mastocytosis, requires better understanding.

To better understand the diagnostic journey, symptom severity, impact on quality of life and work/activities, and health care utilization of ISM.

Survey data were collected from 40 adults with documented ISM meeting World Health Organization 2016 criteria, including validated questionnaires (ISM Symptom Assessment Form [ISM-SAF] and Short Form Quality of Life Survey [SF-12v1]). Spearman correlation coefficients determined the associations between the ISM-SAF Total Symptom Score (TSS) and SF-12v1 scores. ISM burden was compared based on moderate/severe compared with mild TSS scores using Kruskal-Wallis and Fisher exact tests.

Patients were aged 56.0 ± 13.0 years, 65.0% female, 62.5% White, and 22.5% Hispanic patients. ISM diagnosis took >2 years in 40%, required ≥6 visits in 47.5%, and was considered moderately/extremely difficult in 50% of patients. Nearly half experienced symptoms daily and rated severity somewhat/significantly worsened since diagnosis. The overall TSS was 27.4 ± 16.2 (mean ± standard deviation). SF-12 Physical Component Summary (PCS) (46.7 ± 11.4) and Mental Component Summary (MCS) (47.6 ± 10.2) scores were lower than the general population score of 50. Moderate correlations (P < .001) were found between TSS and the PCS (ρ = -0.6406; P < .001) and MCS (ρ = -0.5104; P < .001). Compared with patients with mild severity (TSS < 28; n = 21), patients with moderate/severe severity (TSS ≥ 28; n = 19) evidenced significantly higher skin and gastrointestinal symptom scores (both, P ≤ .001). ISM's impact on ability to work for pay was associated with TSS (P = .004). Symptom-directed treatment had limited effect.

ISM was self-reported as a burdensome condition in half the patients that markedly affected daily living.