Estimated burden of fungal infections in Italy

Introduction
Fungal infections are a significant and increasing public health problem worldwide, that range in severity from mild superficial infections that affect a large proportion of the otherwise healthy population to life-threatening invasive diseases limited mostly to vulnerable immunosuppressed patients (1).
Patients that are at risk for fungal infections, those hospitalised with serious underlying diseases, such as those with HIV infection, haemato-oncological malignancies, recipients of immunosuppressive therapies, solid-organ or hematopoietic stem cell transplant (HSCT) recipients (2).
The incidence of fungaemia is growing and has dramatically increased within the past two decades. Such infections have been attributed to the common practice of prolonged hospitalisation of highly susceptible patients receiving advanced medical treatment; such conditions render patients more susceptible to invasive fungal infections (3,4)
The populations of patients at risk have expanded to include those with usually multiple underlying medical conditions, such as diabetes mellitus, chronic obstructive pulmonary diseases and those receiving corticosteroids (3,4)
The current number of fungal infections occurring each year in Italy is not known. The aim of this work was to estimate the burden of fungal infections in Italy, a country, with a population of 61 millions. As invasive fungal infections are not reportable, exact data are not available. For this reason, we have taken different approaches to explore the current number of invasive fungal infections. First, we have estimated fungal infections based on populations at risk, with data from published Italian or international cohort studies and clinical trials.
Material and methods
The burden of serious fungal infections was estimated for general healthy population and for specific at-risk groups, including patients affected by HIV infection, respiratory diseases (COPD, asthma and tuberculosis), solid organ or hematologic malignancy and critical illness.
Demographic data regarding Italian population were obtained from the Italian National Statistical Institute (ISTAT) (5).
Data on the HIV/AIDS population were obtained from the Epicentro-National Institute of Health (Istituto Superiore di Sanità-ISS) (6) and recent published data estimating adult HIV prevalence in Italy (7).
Tuberculosis statistics were taken from the Epicentro-National Institute of Health (ISS) (6) and World Health Organization (WHO) reports (8). COPD and asthma prevalence in Italy were obtained from the Health Examination Survey (OEC/HES) 2008-2012(9).
Solid organ cancer and haematological diseases cases were taken from Associazione Italiana Oncologia Medica (AIOM) (10) and Associazione Italiana dei Registri Tumori (AIRTUM) reports (11).
Country’s profile, populations and rates required to calculate burden of serious fungal infections are reported in Table 1.
We conducted an extensive literature review and published epidemiology papers reporting fungal infections incidence and/or prevalence in Italy were identified.
Where no national data existed, authors reviewed data from published single-center or multicentre trials and from public health institutions in Italy. Moreover, in selected cases, when Italian data were not available, we calculated Italian fungal burden based on fungal infection incidence in other European countries.
RESULTS
Country profile
Italy is a country with an estimated population of 61 million people, represented by adults ( 14 years) in up to 85% of cases. Of the general population, approximately 13 million (22%) are older than 65 years. Chronic obstructive pulmonary disease prevalence has been estimated in 3.5-5% in men and 2.3 - 3.3% in women overall among adult population, with the large majority of patients in classified as GOLD stage I. The number of HIV-infected patients ranged between 114.000 and 156.000 people, with approximately 84% of patients receiving ARV (7). Solid organ cancer prevalence is 3.037.127 cases, accounting for approximately 5% of overall population (11). The exact prevalence of patients with hematological malignancies is not available, but an estimated number of 31.300 new diagnosis per year, mainly represented by non-Hodgkin lymphoma and acute leukemia has been reported in Italian registries (11). The number of autologous and allogeneic HSCTs is available at the registry of the Gruppo Italiano Trapianto di Midollo Osseo (GITMO) and accounted in 2016 for 2905 and 1796 transplants, respectively (www.gitmo.it). Country’s profile, populations and rates required to calculate burden of serious fungal infections are reported in Table 1.
Prevalence rates previously reported used to estimate the burden of serious fungal infections are reported in Table 2.