INDOLENT SYSTEMIC MASTOCYTOSIS IN FRANCE: A FIRST ESTIMATION OF THE ANNUAL MEDICAL AND SOCIOECONOMIC BURDEN
Author(s)
Charles-Antoine Schwerer, MSc1, Pierre-Guive Yazdani, MSc1, Cristina Bulai Livideanu, MD, PhD2, Julien Rossignol, MD, PhD3.
1Asterès, Paris, France, 2Hôpital Larrey, Toulouse, France, 3Hôpital Necker Enfants Malades, Paris, France.
1Asterès, Paris, France, 2Hôpital Larrey, Toulouse, France, 3Hôpital Necker Enfants Malades, Paris, France.
OBJECTIVES: Indolent systemic mastocytosis (ISM) is a rare, chronic disease that impairs the quality of life of most patients and whose prevalence is increasing in France. As no health economic study has yet been conducted in Europe, this study estimates the annual medical and socioeconomic costs of ISM in France, including patients in diagnostic wandering.
METHODS: A cost-of-illness model was developed from a systematic literature review and expert interviews. ISM prevalence was estimated by combining French diagnosed prevalence (Rossignol et al., 2025: 4.5 per 100,000 adults) with a diagnostic wandering population derived from the gap with Danish registry data (Jorgensen et al., 2025: 27.0 per 100,000), yielding 13,400 adults in France: 3,100 diagnosed and 10,300 in diagnostic or therapeutic wandering. Direct medical costs included consultations, diagnostic tests, and drug treatments, valued using 2025 French official tariffs; hospitalizations were excluded for lack of robust data. Socioeconomic costs included labour market exits, reduced working time, early retirement, and disability; absenteeism and presenteeism were excluded. Costs were allocated across patients, employers using a cumulative friction cost method, and public payers.
RESULTS: Total annual ISM burden in France was estimated at ~€150M, of which 83% was socioeconomic and 17% direct medical. Direct medical costs ranged from €15M to €32M depending on drug utilization assumptions. Socioeconomic costs were driven by labour market exits: patients bore €64M in lost income, public bodies €50M in increased expenditure, and employers €10M in cumulative friction costs. For patients with disrupted work trajectories, the annual socioeconomic cost reached €23,300.
CONCLUSIONS: ISM generates a substantial economic burden in France, dominated by socioeconomic impacts, with diagnostic wandering accounting for 78% of total costs. These findings highlight the economic relevance of reducing diagnostic delay and improving disease management pathways. This estimate is conservative, as hospitalizations, absenteeism, presenteeism, quality-of-life impacts, and patient out-of-pocket expenditures were excluded.
METHODS: A cost-of-illness model was developed from a systematic literature review and expert interviews. ISM prevalence was estimated by combining French diagnosed prevalence (Rossignol et al., 2025: 4.5 per 100,000 adults) with a diagnostic wandering population derived from the gap with Danish registry data (Jorgensen et al., 2025: 27.0 per 100,000), yielding 13,400 adults in France: 3,100 diagnosed and 10,300 in diagnostic or therapeutic wandering. Direct medical costs included consultations, diagnostic tests, and drug treatments, valued using 2025 French official tariffs; hospitalizations were excluded for lack of robust data. Socioeconomic costs included labour market exits, reduced working time, early retirement, and disability; absenteeism and presenteeism were excluded. Costs were allocated across patients, employers using a cumulative friction cost method, and public payers.
RESULTS: Total annual ISM burden in France was estimated at ~€150M, of which 83% was socioeconomic and 17% direct medical. Direct medical costs ranged from €15M to €32M depending on drug utilization assumptions. Socioeconomic costs were driven by labour market exits: patients bore €64M in lost income, public bodies €50M in increased expenditure, and employers €10M in cumulative friction costs. For patients with disrupted work trajectories, the annual socioeconomic cost reached €23,300.
CONCLUSIONS: ISM generates a substantial economic burden in France, dominated by socioeconomic impacts, with diagnostic wandering accounting for 78% of total costs. These findings highlight the economic relevance of reducing diagnostic delay and improving disease management pathways. This estimate is conservative, as hospitalizations, absenteeism, presenteeism, quality-of-life impacts, and patient out-of-pocket expenditures were excluded.
Conference/Value in Health Info
2026-11, ISPOR Europe 2026, Vienna, Austria
Value in Health, Volume 29, Issue 12S
Code
EE407
Topic
Economic Evaluation
Topic Subcategory
Cost/Cost of Illness/Resource Use Studies, Work & Home Productivity - Indirect Costs
Disease
Rare & Orphan Diseases