An established dogma of autopsy pathology is that it is not possible to ascertain a cause of death in about 2–5% of postmortems.1 One of the most common reasons for a cause of death to be unascertained is due to postmortem decomposition. Decomposition change can affect the macroscopic and microscopic appearances of pathology and can introduce uncertainty into the interpretation of postmortem findings.2 Postmortem decomposition is also an increasingly recognised sign of perimortem social isolation.3

But what is the actual relationship between postmortem decomposition and unascertained deaths? There have not been many studies examining the relative frequencies of these phenomena. We intend to present our own data in combination with the few other studies available, as a mini meta-review, to establish some definitive figures.

We reviewed the reports of all 913 routine, adult, coronial postmortems undertaken or supervised by three consultant pathologists in the year 2019 and the 12 months from April 2022 to March 2023.

An autopsy was classed as ‘decomposed’ if the report referred to findings of ‘moderate’, ‘marked’, ‘severe’ or ‘advanced’ decomposition change as well as some qualifier explaining what this constituted (eg, ‘mummification of the face’). Cases with findings suggestive of only early decomposition change (eg, ‘greening of the abdomen’) were excluded from the final ‘decomposed’ count. Causes of death given as ‘1a unascertained’ or equivalent were also tallied.

There have not been many quantitative studies of postmortem data where these two variables have both been presented to facilitate …