Reply:
Authors: Michael A. Heneghan, Andrew D. Yeoman
Journal: Hepatology (2009)

We thank Drs. Kochar and Fallon for their comments regarding our study assessing the utility of the simplified International Autoimmune Hepatitis Group (IAIHG) group criteria for the diagnosis of autoimmune hepatitis (AIH) and wish to take this opportunity to respond to their comments in turn. First, the diagnosis of AIH at our institution is made based on a global assessment of clinical, biochemical, immunological, and histological parameters. Our understanding of AIH represents that of a tertiary center with a long-standing interest in both the diagnosis and management of autoimmune liver disease, and the cohort described in our validation study represents the distillation of more than 35 years of institutional experience, much of which was derived prior to the creation of either the original IAIHG criteria published in 1993,1 or indeed the revised criteria published in 1999.2-4 The revised 1999 IAIHG criteria were not used as the "de facto" gold standard,4 although all patients in our recently published study met the revised 1999 IAIHG group criteria for a probable or definite diagnosis of AIH.5 This finding, however, is not out of keeping with validation studies of the original criteria which report 97%–100% sensitivity for this iteration of the diagnostic criteria. Indeed, the very same caution that Drs. Kochar and Fallon advise to our validation study can be applied to the report of simplified criteria from the IAIHG study group itself.6 The very absence of a gold standard makes assumptions in relation to a correct diagnosis of AIH. Second, although we agree that the inclusion of only patients who had all the appropriate data available were included in our study could lead to selective inclusion of patients, it can be argued that the converse is equally true regarding selective exclusion. Furthermore, our study set out to evaluate the accuracy of the simplified criteria in comparison to the 1999 revised criteria and this, self-evidently, is not feasible if we ignore parameterrs relevant to these individual scores. Third, for a disease process such as AIH, it is important to acknowledge that the diagnosis cannot be made in every individual "at the bedside", and what evaluation of the simplified criteria highlights well is the difficulty of doing so for these patients. In all aspects of clinical practice, the "one size fits all" paradigm never quite manages to exist, and it has been a long-held opinion of the authors that despite all iterations of criteria, the diagnosis of AIH remains a clinical one, given the propensity of some patients to change disease phenotype over time.7, 8 Moreover, we feel that a "diagnostic" trial of corticosteroids remains clinically very useful and as Drs Kochar and Fallon rightly point out, such a consideration would not increase the complexity of the criteria such that it would limit their applicability. Finally, we agree with Drs. Kochar and Fallon that the "overall" sensitivity of any diagnostic criteria remain the most important aspect in terms of its implementation. However, one of the key findings of our validation study was that, in comparison with the more comprehensive diagnostic 1999 criteria, the simplified criteria identifies fewer patients with what we consider as classical AIH (93% versus 100%), and this to us remains a concern. Consequently, we are also in agreement that until a gold standard is identified for the diagnosis of AIH, any criteria should be used as an adjunct or supplement to the clinical judgement that we at our institution continue to employ in diagnosing and managing AIH. Michael A. Heneghan MD, FRCPI*, Andrew D. Yeoman MB, MRCP*, * Institute of Liver Studies, King's College Hospital, Denmark Hill, London, United Kingdom.