Wilson's disease in Spain: validation of sources of information used by the Rare Diseases Registries

Abstract

OBJECTIVE: To evaluate the sources of information used by the Regional Population-based Registries of Rare Diseases (RRD) for Wilson's Disease identification in Spain; to calculate its prevalence and mortality; and to describe the sociodemographic characteristics of those affected. METHOD: Cross-sectional epidemiological study, period 2010-2015. Possible cases were identified by codes 275.1 (ICD-9-CM), E83.0 (ICD-10) and 905 (ORPHAcode) in: 15 participating RRD and the Rare Disease Patients Registry of the Carlos III Health Institute. The diagnoses were confirmed through a clinical documentation review. The positive predictive value (PPV) of the sources of information used by RRD and their combinations were obtained. The prevalence, mortality and the distribution of sociodemographic characteristics were calculated. RESULTS: The Hospital Discharge Database (HDD) was the most used source by the RRD (PPV=39.4%), followed by the Orphan Drugs Registry (ODR) (PPV=81.9%). The Clinical History of Primary Care (PC) obtains PPV=55.9%. The combinations with highest PPV were the ODR with HDD (PPV=95.8%) and the ODR with PC (PPV=92.9%). 514 cases were confirmed, 57.2% men, with a median age of diagnosis of 21.3 years. The prevalence was 1.64/100,000 inhabitants in 2015 and mortality rate was 3.0%, being both higher in men. CONCLUSIONS: Incorporation of ODR and PC into the RRD is recommended, as its combination and ODR with HDD could be used as an automatic validation criterion for Wilson's disease. The prevalence obtained was similar to that of countries close to Spain.