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

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

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

Methods: 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.

Results: 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.

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