Studies of avoidable factors influencing death: a call for explicit criteria

To analyse studies evaluating cases of potentially "avoidable" death.

The definitions, sources of information, and methods were reviewed with a structured protocol. The different types of avoidable factors,--that is, deficiencies in medical care that may have contributed to death--were categorised. The presence of explicit classifications and standards was examined. basic criteria for quality of the studies were defined and the numbers of studies fulfilling these criteria were assessed.

65 studies, published during 1988-93 in peer reviewed medical journal for which the title, or abstract, or both indicated that they had analysed potentially avoidable factors influencing death. Studies analysing aggregated data only, were not included.

Only one third of the studies fulfilled basic quality criteria,--namely, that the avoidable factors examined should be defined and the sources of information and people responsible for the judgements presented. The definitions used comprised two levels, one stating that there had been errors in management (process) and the other that the errors may have contributed to the deaths (outcome). Only 15% of the studies explicitly defined what type of factors they had looked for and 8% referred to specified standards of care.

Studies of avoidable factors influencing death may have considerable potential as part of a system of improving medical care and reducing avoidable mortality. At present, however, the results from different studies are not comparable, due to differences in materials and methods. There is a need to improve the quality of the studies and to define standardised explicit definitions and classifications.