Study design and preliminary results from the pilot phase of the PraKtis study: self-reported diagnoses of selected skin diseases in a representative sample of the Italian population

Abstract

Background: Few data are available on the prevalence of common skin disorders like actinic keratoses in the general population. Such data are mostly needed to better define health needs and to organize medical services. The Prevalence of Actinic Keratoses in the Italian Population Study (PraKtis) was designed to estimate the point prevalence of actinic keratoses and related disorders, e.g. photoaging, in a representative sample of the Italian population. Within the study, information on the history of relevant dermatological diagnoses was also collected.

Methods: The study was conducted in collaboration with DOXA, the Italian branch of the Gallup International Association. A representative sample of people aged 45 years or older was selected by picking them from the electoral rolls according to a stratified random sampling design involving a replacement procedure. A total of 180 interviewers specifically trained to collect data on skin diseases and to take photographs of representative lesions on the face and upper limbs, contacted and interviewed the sampled subjects and performed a face-to-face computer-assisted interview. A final sample of about 12000 subjects was foreseen.

Results: The pilot phase of the study was conducted between January 1 and June 30, 2003. A total of 3660 subjects were recruited and interviewed. Overall, an estimated 37% of Italian people reported having ever undergone a dermatological consultation in the past. An estimated 29% reported having ever received a specific dermatological diagnosis by a physician. The frequency of specifically enquired diagnoses, weighted according to the distribution of the Italian population, was as follows: atopic dermatitis 4.7%, other eczematous dermatitides 4.3%, urticaria 4.3%, psoriasis 3.1%, skin tumors 1.6%, vitiligo 0.7% and actinic keratoses 0.3%.

Conclusion: Skin diseases are frequently reported. The prevalence of actinic keratoses according to self-reported diagnoses was lower than expected based on prevalence data obtained by directly examining people. These discrepancies may be due to underreporting and/or unawareness of lesions by affected people. More precise estimates will be obtained by direct examination of sampled people.