Accuracy of death certificates for amyotrophic lateral sclerosis varies significantly from north to south of Italy: implications for mortality studies.
ABSTRACT 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.
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 ALS according to the Scottish Motor Neuron Disease Research Group diagnostic criteria were included. DCs were obtained from the vital statistic bureau. True positive rates (TPRs) and 95% confidence intervals (CIs) for proportions were calculated for northern and southern Italy separately. Multiple logistic regression analysis was performed according to gender, age at onset, age and year of death, and interval between onset and death.
We found 651 patients affected by definite/probable ALS; 573 of them had died by December 31, 1996. DCs were available for 566 subjects (411 from northern Italy and 155 from southern Italy). TPR was 66.7% (95% CI 61.9-71.2) for northern Italy and 51.6% (95% CI 43.5-59.7) for southern Italy (chi(2) = 10.9, p = 0.001). Logistic regression analysis showed an association between a lower accuracy of DCs and the interval between onset of symptoms and death. TPR calculations considering different death periods (1970-1982 and 1983-1996) showed comparable rates of accuracy over time.
Mortality statistics based on official death records do not accurately reflect interregional mortality for ALS in Italy.
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ABSTRACT: The El Escorial diagnostic criteria are the most commonly used in clinical studies and therapeutic trials in patients with amyotrophic lateral sclerosis (ALS). The accuracy of the El Escorial criteria was tested in clinical practice, but the reliability is unknown when the diagnosis of ALS must be assessed on the basis of medical records. To assess the reliability of the El Escorial criteria for the diagnosis of ALS in different settings. Semistructured forms were used to include the main diagnostic information on 20 patients with definite (n = 6), probable (n = 6), possible (n = 6), and suspected ALS (n = 2) and 19 patients with clinical conditions considered in the differential diagnosis. Agreement was tested by comparing the diagnosis made by the attending physician (the 'gold standard') with that of 4 raters with different backgrounds: a teaching neurologist with research and practical experience in the field of motor neuron disorders, a neurologist with specific interest in motor neuron disorders and neurophysiological background, a neurophysiologist, and a general neurologist with only occasional ALS patients. Sources of disagreement were discussed and the agreement was tested further on the medical records of 98 additional cases taken from an ongoing ALS registry. Eight additional cases (ALS: 4; other conditions: 4) were examined directly by the 4 raters. The interrater agreement on the medical records was poor (overall kappa 0.05-0.29). When the differential diagnosis was made between ALS (all diagnostic levels) and other conditions, interrater agreement was at best modest, with moderate variations when raters were compared in pairs (kappa 0.03-0.58) and when each rater was compared with the physician (kappa 0.27-0.51). Agreement was higher after direct examination of the patients (kappa 0.33-1) and increased significantly on the medical records after training (overall kappa 0.52-0.79). However, concordance was low (overall kappa 0.08-0.36), even after training, at the lowest diagnostic level (definite to suspected ALS vs. other conditions). The El Escorial criteria are a poor diagnostic indicator when patients' records are examined. Although medical education significantly improves the reliability of the criteria, concordance is still modest when the diagnosis includes suspected ALS.Neuroepidemiology 01/2002; 21(6):265-70. · 2.37 Impact Factor
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ABSTRACT: Recent surveys indicate a decreasing north-to-south gradient in the mortality and incidence rates of amyotrophic lateral sclerosis (ALS) in Italy, possibly indicating a different susceptibility to ALS in these populations. Piemonte, a region of northwestern Italy, experienced a considerable migration from other regions in Italy between 1940 and 1975; we therefore analyzed the effects of place of birth and migration upon the risk of developing ALS. Data on all ALS cases occurring in Piemonte during the period 1971-1990 were collected. Standardized incidence ratios (SIRs) for patients born outside Piemonte were calculated, using the Piemonte-born population as reference. A total of 962 ALS cases were identified during the study period, corresponding to a mean annual crude incidence rate of 1.37/100,000 population (95% confidence interval, 1.29-1.46). The SIRs of patients born in three southern Italian regions and of foreign-born persons were significantly higher than those of persons born in Piemonte and or other regions in Italy, and increased with age. This observation may be explained by an interaction between environmental and genetic factors or by selective migration.Journal of Neurology 04/1999; 246(3):175-80. · 3.58 Impact Factor
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ABSTRACT: The aim was to determine the reliability of official mortality statistics in estimating long term trends of amyotrophic lateral sclerosis (ALS) in Italy. The study was a mortality follow up of cases of ALS. Piedmond Region, northern Italy. Cases of ALS were identified from multiple sources between 1966 and 1985. Cause of death was determined for the cases who died between 1970 and 1985. Death certificates were obtained in 488 out of 510 cases (95.7%). ALS was mentioned in 365 (74.8%) of cases. The most frequent erroneous diagnoses were multiple sclerosis and malignant tumours. Demographic variables, such as sex, age at death, province of death, and calendar year of death, did not influence the percentage of true positive cases significantly. The death certificate diagnosis of ALS appears to be adequate for use in descriptive and analytical epidemiology.Journal of Epidemiology & Community Health 11/1992; 46(5):517-8. · 3.39 Impact Factor