Accuracy of death certificates for amyotrophic lateral sclerosis varies significantly from north to south of Italy: Implications for mortality studies

<i>Objective:</i> To evaluate the accuracy of death certificates (DCs) for amyotrophic lateral sclerosis (ALS) in different parts of Italy. Studies based on DC diagnosis for ALS have shown a reduced mortality comparing northern with southern Italy. These data are in contrast with results from other surveys on the incidence of ALS performed in Italy and other countries. <i>Methods:</i> Archives of neurological clinics from northern (Milano, Monza, Pavia, and Bologna) and southern Italy including islands (Napoli, Sassari, Palermo, and Messina) were searched for patients discharged with a diagnosis of ALS in the period 1970–1995. Subjects affected by definite/probable A…