Loss of tolerance and overdose mortality with detoxification

Editor—Strang et al reported fatal overdose in three former inpatients among 137 who attempted to detoxify from heroin dependence in south London.¹ They claim that overdose deaths up to four months after discharge occurred only among the detoxified patients who completed their 28 day programme, who at the time of death were assumed to have none of their former tolerance for opiates.

Instead of basing their analysis on the three adverse events related to their hypothesis about overdose mortality, Strang et al present only statistics on all cause mortality (five patients in total died). All three patients with fatal overdoses completed a programme, compared with 34 of the 134 patients who did not have a fatal overdose. If just one of these three deaths was not an accidental dose miscalculation but an intentional suicide, the importance of the study is reduced. More importantly, the three patients had been living alone compared with only 22 of the 132 who survived.

Adverse events such as patients' deaths should be interpreted in the light of “near misses” and the context in which untoward incidents occur. For example, to interpret 17 serious adverse events requiring immediate medical treatment in the same hospital as that of Strang et al, my colleagues and I had to investigate 1000 untoward incidents, including many near misses.²

Strang et al do not present the pattern of non-fatal overdoses across their patient population. Is this really a study about tolerance or about access to help? A poverty of social capital and solidarity among drug users,³ may be the major factor for their survival. Let us guess that a couple of dozen former patients overdosed (either accidentally or intentionally), but whereas three were living alone and unobserved, the others got help and survived.