1 Rheumatic Diseases Unit,
2 University Department of Medicine, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK.
SIR, We read with interest the paper entitled Risk taking in patients with rheumatoid arthritis: are the risks of haemopoietic stem cell transplantation acceptable? by Snowden et al. [1]. They cited two previous studies [2, 3] demonstrating that rheumatoid patients were willing to accept a high risk of death, of 27 and 26.8% for cure from their rheumatoid arthritis. Curiously, they did not mention the two other studies reported by our group, which produced quite different results. Our patients were only willing to risk a 1:100 000 risk of death for a complete cure [4], and a 1:10 000 000 risk of death for a 90% chance of complete cure [5]. We do not believe that the methodology of their study allows an accurate or realistic assessment of patients' attitudes to the risks/benefits of stem cell transplantation, or indeed any other potentially curative treatment for rheumatoid arthritis, for the following reasons.
The question asked What risk of death would you accept ... return you from your present state of health back to complete normality ... suggests firstly, that the cure includes all co-morbidity and not just rheumatoid arthritis; second, it indicates that all of the rheumatoid disease including joint destruction/deformity would be completely reversed which clearly would not be the case in a cure. The latter part of the question ... for the rest of your life without any need for medications indicates that the treatment offered would also prevent the recurrence of rheumatoid arthritis and also the development of any other diseases in the future. Clearly, if presented with this cure-all, reverse-all, prevent-all treatment, one might anticipate a higher degree of risk taking than for a treatment that simply cures rheumatoid arthritis. We appreciate, however, that patients do have difficulty with the concept of cure, and found, e.g. that hip surgery appeared to be more deserving of risk taking than a complete cure for rheumatoid arthritis [4].
A further cause for concern is the standard gamble technique used and this was discussed in a previous publication [4]. Although this technique allows for 0% or no risk accepted the next risk offered is 1% or 1:100 risk of death, thereby completely ignoring smaller and clinically more appropriate risk levels, e.g. 1:1000, 1:10 000. This represents an immediate and major bias. The median risk accepted was 8% which is in the lowest 10 percentile of risk levels offered (1100%). If a different scale had been offered to include lower risk levels, then selection of a risk in the lowest 10 percentile would produce quite different results. The results of such studies are, we believe, dependent to a large extent on the methodology used and we plan to conduct a further study comparing the different methodologies. With regard to this study, however, we feel that it would be quite inappropriate to extrapolate the results to answer the question are the risks of haemopoietic stem cell transplantation acceptable to patients with rheumatoid arthritis?
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