Editor,—Dr Stephen Glen and his coauthors conclude from an analysis of medical records held by the Scottish Sub-Aqua Club (SSAC) that routine medical examination of sport divers can safely be replaced by a system of self declaration, with a questionnaire designed to indicate whether referral to a doctor with experience of diving medicine is necessary.¹ This conclusion should be regarded as preliminary, however, because the data were not disaggregated sufficiently to reveal the additional screening value of a routine medical examination beyond that of an initial questionnaire. In addition, there are inherent statistical biases in the SSAC data that have not been addressed.

The risks associated with discontinuing routine examinations could have been investigated by quantifying the number of cases in which disqualifying conditions were found in medical examination but not declared in the prior questionnaire. However, the authors' listing of abnormalities recorded at examination apparently includes those due to conditions declared in the questionnaire. Similarly, the listing of formal referrals to approved medical referees does not indicate how many were initiated by a questionnaire response and how many as a result of an examination finding only. Crucially, the cases that were …