LETTERS TO THE EDITOR
SURVIVAL PREDICTION IN AMYOTROPHIC LATERAL SCLEROSIS We agree with Jablecki, Berry, and Leach’ that quantification of survival data would be useful to clinicians managing patients with ALS. Their paper is a first attempt at this, but there is a considerable distance to go before they can claim to be able to predict survival from one clinical observation and a disease duration based upon a patient’s memory. It is our experience that patients have considerable difficulty pinpointing the onset of symptoms in ALS. Table 4,which they suggest using to calculate survival, has considerable variability even if the onset of symptoms is accurate, which further limits its usefulness. The individual patients whose survival they predict all outlived that prediction. It is surprising that a bias exits in this direction since the rapid progress of disease that they report right before deaths would suggest a bias in the other direction. Finally, it is difficult to believe, as they suggest on page 839, that a single observation and a patient’s memory of duration is better than two successive observations of disease progression. The authors have the right idea, but more work is needed before their prediction can be reliably used. James R. Murphy, PhD Steven P. Ringel, MD Neuromuscular Section Department of Neurology School of Medicine University of Colorado Health Science Center Denver, Colorado 1 . Jablecki, CK, Berry C, Leach, J: Survival prediction in amyotrophic lateral sclerosis, Muscle Nerve 1989;129333-841.
SURVIVAL PREDICTION IN ALS: A REPLY Over the last 10 years, w e developed the method for survival prediction in ALS described in our article. During that time, this prediction technique has been used successfully to help individual patients make decisions regarding personal plans and medical care. Figure 2 (page 836) provides a detailed example of use of
the survival predictions to make clinical decisions for patient JC regarding travel, surgery, and nursing home placement. Also the method has been used to refer ALS patients to services that provide limited care for terminal patients. Because of the success of these predictions, San Diego Hospice is the one Hospice in the United States that will accept ALS patients for one year of terminal care. In fact, 19 of 20 ALS patients referred to San Diego Hospice with a predicted survival time of less than one year died within that year. An accurate prediction of ALS patients requires careful history taking to determine the date of onset of symptoms. It helps to interview both the patient and his relatives to find a specific activity that deteriorated and to use specific dates such as holidays, birthdays, vacations, and other memorable dates to identify the month and year that the first symptom or sign of weakness was noted. Taking the history is a learned clinical skill that improves with experience. The date of onset can be determined with reliability if one spends sufficient time interviewing the patient and others close to him. Murphy and Ringel indicate that Table 4 (page 839), the table used to make the survival predictions, has considerable variability so that even if the date of onset of symptoms is accurate, the usefulness of the survival prediction is limited. It should be noted that Table 4 provides explicit quantification of the variability in survival among patients with similar Q values and ages. The variability shown in any cell of Table 4 is much less than the variability in survival for all ALS patients of different ages and different Q values. We believe that the usefulness of the approach has been demonstrated by the success of the predictions in a clinical setting as noted above. Table 5 (page 840) demonstrates the application of our method to individual patients by several clinicians whose experience with the method was limited to a 30 minute training session. Murphy and Ringel state that the individual patients whose survival was predicted all outlived that prediction. All but one (PS) of these eight patients have since died. Some lived longer than their predicted (median) survival and some did not. Overall, their survival experience was consistent with the predictions of Table 4.
MUSCLE & NERVE
July 1990
657
Murphy and Ringel suggest that it would be better to predict survival from two examinations at different times than from one examination and an historical date of onset of symptoms. This is an hypothesis that can be tested, and we did test it. Though both methods provided survival predictions that correlated well with the actual survival time, the survival prediction based on a visit and an historical date of onset was better than a survival prediction based on changes in the ALS score between two visits (page 839). If Murphy and Ringel have independent data to support their suggestion, we would be interested in reviewing it. Murphy and Ringel contend that the survival predictions cannot be used reliably, but these survival predictions are being used successfully to make decisions
658
regarding patient care and use of medical resources. The method is simple, straightforward, depends on skills already taught to physicians, and can be integrated into the initial and follow-up history and examination. We look forward to hearing from clinicians who will use our examination technique and the ALS survival prediction system with their own patients regarding their experience. Charles Jablecki, MD Department of Neurosciences Charles Berry, PhD Department of Community and Family Medicine University of California San Diego San Diego, California
MUSCLE & NERVE
July 1990
SURVIVAL PREDICTION IN AMYOTROPHIC LATERAL SCLEROSIS We agree with Jablecki, Berry, and Leach’ that quantification of survival data would be useful to clinicians managing patients with ALS. Their paper is a first attempt at this, but there is a considerable distance to go before they can claim to be able to predict survival from one clinical observation and a disease duration based upon a patient’s memory. It is our experience that patients have considerable difficulty pinpointing the onset of symptoms in ALS. Table 4,which they suggest using to calculate survival, has considerable variability even if the onset of symptoms is accurate, which further limits its usefulness. The individual patients whose survival they predict all outlived that prediction. It is surprising that a bias exits in this direction since the rapid progress of disease that they report right before deaths would suggest a bias in the other direction. Finally, it is difficult to believe, as they suggest on page 839, that a single observation and a patient’s memory of duration is better than two successive observations of disease progression. The authors have the right idea, but more work is needed before their prediction can be reliably used. James R. Murphy, PhD Steven P. Ringel, MD Neuromuscular Section Department of Neurology School of Medicine University of Colorado Health Science Center Denver, Colorado 1 . Jablecki, CK, Berry C, Leach, J: Survival prediction in amyotrophic lateral sclerosis, Muscle Nerve 1989;129333-841.
SURVIVAL PREDICTION IN ALS: A REPLY Over the last 10 years, w e developed the method for survival prediction in ALS described in our article. During that time, this prediction technique has been used successfully to help individual patients make decisions regarding personal plans and medical care. Figure 2 (page 836) provides a detailed example of use of
the survival predictions to make clinical decisions for patient JC regarding travel, surgery, and nursing home placement. Also the method has been used to refer ALS patients to services that provide limited care for terminal patients. Because of the success of these predictions, San Diego Hospice is the one Hospice in the United States that will accept ALS patients for one year of terminal care. In fact, 19 of 20 ALS patients referred to San Diego Hospice with a predicted survival time of less than one year died within that year. An accurate prediction of ALS patients requires careful history taking to determine the date of onset of symptoms. It helps to interview both the patient and his relatives to find a specific activity that deteriorated and to use specific dates such as holidays, birthdays, vacations, and other memorable dates to identify the month and year that the first symptom or sign of weakness was noted. Taking the history is a learned clinical skill that improves with experience. The date of onset can be determined with reliability if one spends sufficient time interviewing the patient and others close to him. Murphy and Ringel indicate that Table 4 (page 839), the table used to make the survival predictions, has considerable variability so that even if the date of onset of symptoms is accurate, the usefulness of the survival prediction is limited. It should be noted that Table 4 provides explicit quantification of the variability in survival among patients with similar Q values and ages. The variability shown in any cell of Table 4 is much less than the variability in survival for all ALS patients of different ages and different Q values. We believe that the usefulness of the approach has been demonstrated by the success of the predictions in a clinical setting as noted above. Table 5 (page 840) demonstrates the application of our method to individual patients by several clinicians whose experience with the method was limited to a 30 minute training session. Murphy and Ringel state that the individual patients whose survival was predicted all outlived that prediction. All but one (PS) of these eight patients have since died. Some lived longer than their predicted (median) survival and some did not. Overall, their survival experience was consistent with the predictions of Table 4.
MUSCLE & NERVE
July 1990
657
Murphy and Ringel suggest that it would be better to predict survival from two examinations at different times than from one examination and an historical date of onset of symptoms. This is an hypothesis that can be tested, and we did test it. Though both methods provided survival predictions that correlated well with the actual survival time, the survival prediction based on a visit and an historical date of onset was better than a survival prediction based on changes in the ALS score between two visits (page 839). If Murphy and Ringel have independent data to support their suggestion, we would be interested in reviewing it. Murphy and Ringel contend that the survival predictions cannot be used reliably, but these survival predictions are being used successfully to make decisions
658
regarding patient care and use of medical resources. The method is simple, straightforward, depends on skills already taught to physicians, and can be integrated into the initial and follow-up history and examination. We look forward to hearing from clinicians who will use our examination technique and the ALS survival prediction system with their own patients regarding their experience. Charles Jablecki, MD Department of Neurosciences Charles Berry, PhD Department of Community and Family Medicine University of California San Diego San Diego, California
MUSCLE & NERVE
July 1990
