OBJECTIVES. Primary aim of the study was to estimate the epidemiology of patients diagnosed with mycosis fungoides (MF) or Sézary syndrome (SS) in Italian real-world settings. Secondary aim was to evaluate among MF/SS-patients the healthcare costs with the perspective of the Italian National Health Service.

METHODS. A retrospective observational study was performed using administrative data from a sample of Italian settings, including approximately 4million health-assisted individuals. Patients presenting discharge diagnoses for MF(ICD-9-CM code=202.1) or SS (ICD-9-CM code=202.2) during 01/01/2009—31/12/2018(study period) were included. The first discharge date was defined index date. Incidence rate of new diagnoses was calculated for each year of the study period. Incident patients were stratified by age and gender. Prevalence of MF/SS diagnosis was evaluated for the last year of study (2018) stratified by gender. Cost analysis focused on patients alive in years 2017-2018 and included therapies, hospitalization, diagnostic tests/specialist visits.

RESULTS. Overall, 194 MF/SS patients (mean age 64.8 years, 63.4% male) were included. Incidence rate for year 2018 was 1.5/1,000,000 (0.49/1,000,000 for females and 2.56/1,000,000 for males) health-assisted subjects. Considering all study period, incidence rate of new diagnoses was found to increase with age reaching the major peak in the age range 70-79 years (13.73/1,000,000) in both female (10.24/1,000,000) and male gender (17.38/1,000,000). In all age-groups, the incidence appeared higher in males. Prevalence of diagnosed MF/SS-patients was estimated of 27.7/1,000,000 health-assisted subjects (20.5/1,000,000 for females and 35.3/1,000,000 for males). Mean annual costs per patient were €1,673.5 for therapies, €1,631.4 for hospitalizations, €736.1 for diagnostic tests/specialist visits.

CONCLUSIONS. We reported the epidemiology of MF/SS-diagnosed patients in Italian settings of clinical practice; differences from literature could be related to the methodology applied. Epidemiologic data together with healthcare direct costs of MS/SS patients herein reported could contribute to shed light on the real burden of these rare diseases.