Diagnostic delay in rare diseases in the Campania region: addressing ageing, gender disparities, and the "postcode lottery effect" to reduce the patient odyssey.

Our study assessed the time to diagnosis of rare diseases (RDs) in Campania and whether there are determinants of diagnostic delay (DD). Demographic characteristics, date of first medical contact and diagnosis, disease macro-groups, and area of residence of patients were recorded. DD was calculated as the time elapsed (in years) from the onset of symptoms to the RD diagnosis date. Based on the Rare Disease Research Consortium consensus document, a time to diagnosis more than one year was considered DD. A multilevel logistic regression was performed. Seven thousand nine hundred and nine patients were included in the analysis; 47.4% were male. The mean DD was 3.4 years and 46% of patients experienced DD. Predictors of DD were female gender (OR 0.90, 95% CI 0.80–0.98, P < .005), age at diagnosis (OR 1.36, 95% CI 1.27–1.45, P < .001), and province of residence (residence in Naples vs. others; OR 0.80, 95% CI 0.73–0.88, P < .001). Immunological, connective tissue, digestive, genitourinary system diseases, and congenital malformations showed more DD than other disorders. Nearly half of the patients with RD experienced DD. The main determinants of DD were female sex, older age at diagnosis.