Look-backs or investigations into harmful medical events that affect more than one person have become commonplace in medicine. The ethics of disclosing errors to patients in such cases are straightforward and, in many jurisdictions, now mandated by law. Regardless of the ethics, many have understandably worried that disclosure will increase liability exposure. Studies to date have not borne out this concern.1 ,2 Sometimes, however, an event turns out to affect more than one individual. Such large-scale events may involve improperly sterilised reusable equipment, healthcare providers or patients with potentially transmissible infections, or an impaired or incompetent provider who has committed errors affecting multiple patients over many years.

The ethical arguments for disclosing in the setting of large-scale events are less straightforward than for errors affecting individual patients. Without further testing, the subgroup of patients who have actually suffered an injury cannot be distinguished from the group of patients who have not been harmed. Thus providers must consider the ethical imperative to inform patients of a possible injury but also the reality that the risk is often low. This caveat does not, however, eliminate for many patients the stress that may be caused by the disclosure itself. A framework for guiding disclosure in such circumstances has recently been outlined.3 However, the impact of such disclosures on patients’ subsequent care-seeking behaviours has not previously been studied.

Wagner et al4 assess the consequences of large-scale adverse event …