Accuracy of Death Certificates for Motor Neuron Disease and Multiple Sclerosis in the Province of Palermo in Southern Italy

Abstract

Mortality studies based on death certificates (DCs) are relatively inexpensive and easy to conduct. Therefore, they are frequently used to evaluate variations of geographical and temporal patterns, particularly in uncommon diseases. Recent surveys of motor neuron disease (MND) and multiple sclerosis (MS) based on official mortality statistics in Italy showed a decreasing trend of mortality from northern to southern Italy. To evaluate if DCs are homogeneously recorded in Italy and whether or not they can be considered a good instrument for mortality studies, we assessed the accuracy of DCs for MND and MS in the province of Palermo, Italy, and compared our results with those reported in other studies. We searched the archives of the neurological clinic of the University of Palermo for patients affected by one of the two diseases who were residents and were diagnosed in Palermo province. We found 157 patients with definite MND and 360 with clinically definite MS. Seventy-eight out of the 157 MND patients and 43 out of the 360 MS patients had died. Considering the underlying cause of death, the true-positive rate was 48% [95% confidence interval (CI) 36–60%] for MND and 46% (95% Cl 30–62%) for MS. The rates we found for MND were lower than those reported either in Italy or worldwide. This result suggests caution in formulating gradient hypotheses for MND. Concerning MS, the rate we found was low, but similar to that found by others. This indicates that a mortality survey of MS based on DCs is unlikely to be contributory.

Accuracy of Death Certificates for Amyotrophic Lateral Sclerosis Varies Significantly from North to South of Italy: Implications for Mortality Studies

“…A recent study on ALS based on DCs in the Province of Palermo, Sicily, showed lower rates of accuracy compared with previous studies conducted in Italy and in other countries [14]. This study supports the hypothesis that mortality surveys based on official mortality records generate data that are not comparable with other surveys unless study designs and rates of accuracy of DCs are homogeneous.…”

“…The relative stability of TPRs over time has already been reported [5,7,14], which indicates that improvement of the diagnostic procedures is not accompanied by an improved accuracy of the DCs.…”

Amyotrophic Lateral Sclerosis Mortality in 1.9 Million US Cancer Survivors

“…Its most notable limitation is its reliance on death certifi cates for the cause of death in a context where the earlier cancer is a potentially competing cause of death. Although death certifi cates are less reliable than other medical records and may vary by geographic area [23], several studies, although not all [24], have determined that death certificates are reasonably accurate at identifying MND or ALS in a number of industrialized countries [25,26]. In any case, comparison rates are derived from death certifi cates as well.…”

Can Mortality Data Be Used to Estimate Amyotrophic Lateral Sclerosis Incidence?

“…These false-positive cases were, in fact, bulbar or pseudobulbar palsy, cerebrovascular disease [40] , multiple sclerosis (MS) [39] or progressive muscular atrophy [41] . The second type of study is based on morbidity data and retrieval of DC for patients with ALS known to have died [39,[42][43][44][45][46][47] (design type B in table 3 ). Estimations of true positivity rates showed variations from 95% to 49% between countries, and regional differences within a given country [45] .…”