[Show abstract][Hide abstract] ABSTRACT: Background. The El-Escorial criteria are widely used for the diagnosis of amyotrophic lateral sclerosis (ALS). Based on these criteria, the classification of the disease is made according to the level of diagnostic certainty (definite, probable, possible, suspected ALS, no ALS). The reliability of the El-Escorial criteria is unknown when the diagnosis of ALS must be assessed according to medical records, as is usually done with a registry of the disease. Methods. The reliability of the El-Escorial criteria in the hands of different investigators was tested in two subsequent steps, before and after training. First step: Using semi-structured forms, the information reported in the records of 20 patients with ALS and 19 patients with other clinical conditions (considered in the differential diagnosis) was examined separately by four neurologists (raters A through D, with decreasing clinical experience in the field of motor neuron disorders). For each patient, the raters had to make a diagnosis of ALS vs no ALS and, in patients with ALS, of definite, probable, possible and suspected ALS. The inter-rater agreement was tested on pairs of raters using the kappa statistics. Second step: To optimize the use of the El-Escorial criteria, the raters underwent training consisting in a discussion of the cases for which different diagnoses were made during the first step. The inter-rater agreement was further tested on the medical records of 98 additional cases, abstracted by the caring physicians participating in a regional registry of ALS. Results. Before training, the inter-rater agreement, measured by the weighted kappa, was poor for each pair (kappa 0.05 to 0.29). Concordance was at best modest at each diagnostic level. After training, agreement improved for each pair (kappa 0.52 to 0.88), with the lowest concordance for rater D. Agreement remained poor only at the lowest diagnostic level (ALS vs no ALS: kappa 0.08-0.36), mostly for rater D. Conclusion. The El-Escorial criteria are fairly reliable for the diagnosis of ALS according to medical records only after training and in the hands of the most experienced physicians. However, concordance is still poor when considering the lowest diagnostic level, which is relevant to the screening of early ALS cases.
No preview · Article · Nov 2002 · Neuroepidemiology
[Show abstract][Hide abstract] 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.
No preview · Article · Nov 2002 · Neuroepidemiology
[Show abstract][Hide abstract] ABSTRACT: As amyotrophic lateral sclerosis (ALS) is a rare neurological disorder, many sources must be investigated for complete case ascertainment. Hospital discharge diagnoses (HDDs) are a source of administrative data for patients hospitalized for a given disease. The accuracy of HDDs was tested, to assess whether they could be used to trace patients with amyotrophic lateral sclerosis (ALS).
All the HDDs referring to patients with motor neuron disease (MND) (ICD-9 code 335.2) were identified from primary hospital discharge diagnoses made during the years 1994-95 in six target provinces of the Lombardy region in Northern Italy (total population 2922920). The medical records of the patients were reviewed and each patient was then accepted or rejected according to whether he/she did or did not satisfy the El Escorial criteria for the diagnosis of ALS. The ALS discharge diagnoses filed in the study period in the neurology departments of all the regional hospitals were the 'gold standard'. Newly diagnosed patients registered during the year 1998 in the same provinces served for the calculation of the incidence of the disease. Sensitivity, specificity and positive predictive value were calculated. Data were presented separately for all the patients and those who were indicated as first hospital admissions.
During the study period a total of 1012122 hospital discharge records were coded in the six index provinces. The ICD-9 code 335.2 was reported in 408 of these (0.04%). These discharge diagnoses were made in 267 patients, 245 of whom were resident in Lombardy at the time of hospital admission. The hospital records of 237 cases were examined. In 95 of these the medical records showed a diagnosis other than ALS. Other motor neuron diseases were listed for 50 patients. Thirteen additional cases were traced through neurology department files. The sensitivity of the HDDs was 91.6%, the specificity 99.9%, the positive predictive value 65.4%. The corresponding values for first-hospitalized patients were 97.7, 99.9, and 37.3. The overall ALS incidence rate obtained from the HDDs was 2.1 per 100000 (95% CI 1.3-3.3). he corresponding rate calculated after exclusion of the false positives and inclusion of the false negatives was 0.8 (95% CI 0.1-2.1) and that obtained using the 1998 cases registered in the same areas was 1.6 (95% CI 0.7-2.7).
The incidence of ALS is overestimated when HDDs are used for the estimate. Nevertheless, with improved quality, administrative data could be useful for the estimate of prevalence and incidence.