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To evaluate the ability of the Italian Creutzfeldt-Jakob (CJD) register to detect human transmissible spongiform encephalopathy (TSE) cases we compared mortality data from the CJD register with those obtained from death certificates collected by the Italian National Census Bureau (ISTAT) between 1993 and 1999. We used the method of record linkage to compare and integrate data from these two sources. The integrated estimate of TSE deaths was 457: 183 deaths recorded by the CJD register and ISTAT, 210 cases only by the CJD register, and 64 cases only by ISTAT. The average integrated estimated mortality rate was 1.58 deaths per million people per year over the study period and peaked in 1999 at 2.13. This figure is similar to that obtained from data from the CJD register alone in the years 2000–2002. The increase in mortality rates is likely due to an improvement in case ascertainment. The misclassification of cases by ISTAT was above 50% from 1996 onward, suggesting that using only death certificates is not a reliable way to monitor TSE cases in Italy.

We report an estimate of Creutzfeldt-Jakob disease (CJD) deaths in Italy from 1982 to 1996 by using mortality data based on a retrospective review of deaths taken from the mortality data base of the Italian Census Bureau (ISTAT, years 1982–1993), and on the prospective surveillance performed by the Italian National Register of CJD (years 1993–1996). One hundred and ninety-five and 154 deaths attributed to CJD were recorded by ISTAT and the CJD register, respectively. The average annual age-adjusted mortality rate was 0.45 and 0.84 deaths per million for the period 1982–1993 and 1993–1996, respectively. The yearly increase in the number of CJD deaths was mostly due to a rise in the reported deaths among people older than 60 years. The result of the linkage between ISTAT and the CJD register shows that the integrated age-adjusted mortality rate for 1993 was about 1 case per million, similar to the rates observed in other studies and obtained by the CJD register alone in 1996. This study indicates that the data of the CJD register is accurate and therefore important for assessing eventual changes in the characteristics of the disease resulting from bovine spongiform encephalopathy or other new risk factors.