Diagnostic delay in amyotrophic lateral sclerosis: what scope for improvement?

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Abstract

The average time taken from symptom onset to diagnosis in motor neuron disease is many months and has shown no sign of improving despite the introduction of riluzole therapy. We performed a retrospective analysis of the time to diagnosis in 57 patients using a structured interview with the patients and/or their carers. In this cohort, studied in England and Wales, the mean time from onset to diagnosis was 16.2 months. An initial incorrect diagnosis, refusal to consider the diagnosis when it was suggested by the informed patient, failure to consider a neurological cause for the patient’s symptoms, and failure to make early referral to a neurologist were the major factors leading to delayed diagnosis. Bulbar symptoms were more likely to lead to correct diagnosis than limb-onset features. Ten of our patients made the diagnosis by consulting reference books or the Internet before they were informed of it by their physician.

Introduction

With the introduction of a licensed treatment [1] for amyotrophic lateral sclerosis (ALS) and with others in development or undergoing clinical trial, early diagnosis is increasingly important. This applies not only to early treatment having more impact on the disease and hence quality of life of the patient but extends to providing greater scope for inclusion in clinical trials [2]. In addition, the psychological interests of people with ALS and their families are best served by a diagnostic process which is efficient yet compassionate, lacks ambiguity, and provides an early indication of prognosis [3].

There have been previous studies in different countries which have included analysis of time to diagnosis. During the last 25 years, eight epidemiological studies have reported intervals ranging from 11 to 22 months, with little evidence that this interval is becoming shorter [4], [5], [6], [7], [8], [9], [10]. Clearly such lengthy delays in the diagnostic process are unacceptable in the context of an available therapy that prolongs life [1] and a disease with a mean life expectancy for patients of less than three years from diagnosis. Few of these studies address the question of where the delay in diagnosis lies or comment on how the diagnostic process might be improved. Belsh and Shiffman [11] studied case records of 33 patients in the USA and found an initial false negative diagnosis rate of 43%. As might be expected the time to correct diagnosis was significantly longer in these patients. The ISIS study [4] also found a 45% incorrect initial diagnosis rate. Lack of familiarity with the common clinical presentations of ALS and failure to consider the diagnosis were the most likely causes of incorrect diagnosis and, therefore, of delay [12], [13].

Necessarily, the diagnostic process cannot begin until the patient recognises the need for medical attention [2] and, because of the varied presentation of ALS, it is unlikely that this time period could be impacted upon. What happens from that point onwards should be open to influence from within the medical profession. Identification of the factors leading to diagnostic delay should enable more rapid and accurate diagnosis to be achieved. We have studied the different time periods within the diagnostic process as experienced by people with ALS in England and Wales. In this report we describe those factors that appear to lead to delay in diagnosis, outline the potential for improvement, and discuss the constraints imposed by the recognised diagnostic criteria.

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Patients and methods

We collected data retrospectively on the process leading to diagnosis in 64 people with ALS. We recruited these people and, where possible, their families through the Motor Neurone Disease Association (UK) newsletter ‘Thumbprint’. The reason for contact was explained as an investigation into the experience of people with ALS in diagnosis. Information was collected by means of a structured interview carried out by telephone, letter or e-mail with the patient and/or their carer. Six sets of data

Results

The demographics of our sample (Table 1) are similar to those of other reported ALS populations [4], [5], [6], [7], [8], [9], [10]. The median year of diagnosis was 1997 (range 1995–1999). The interviews were carried out in the summer of 1999. The mean time from symptom onset to diagnosis was 16.2 months (S.D. 11.2; range 3–50 months). The mean time from first medical contact related to ALS symptoms to diagnosis was 11.1 months (S.D. 9.8; range 2–44 months). There was no correlation between age

Discussion

The time taken for a diagnosis of ALS to be reached was rapid in some cases but in many others was very long. The average time to diagnosis in our sample of patients in England and Wales was similar to that found in several studies published in the last 25 years from the USA, Europe and South America [4], [5], [6], [7], [8], [9]. Despite the introduction of riluzole and much written in the medical press on the need for faster diagnosis there is no evidence as yet of any consistent improvement

Acknowledgements

We are most grateful to the Motor Neurone Disease Association and its members for their help in facilitating this investigation.

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