We have attempted to classify causes of death on the death certificate and at necropsy by calculating the sensitivity and PPV of the certificate in providing accurate diagnoses. Our study has shown an overall sensitivity (0.47) within limits of previously recorded findings.1–5
The low sensitivity of cardiovascular causes of death is in keeping with other studies showing that underlying cardiac disease is rarely recorded on the death certificate,7
and we have demonstrated a sensitivity in the malignant disease category comparable with other published data.2,8
We have also shown a correct primary site to be established in a higher proportion (84%) of malignant cases, compared with other reports.8
We have shown agreement in the cause of death to be likely in a neurological diagnosis and the diagnosis of respiratory malignancy, possibly because of early presentation or a more clear cut clinical scenario.
The fact that our study is retrospective and is in the setting of the non-coronal necropsy has meant that some histology was not directly related to the cause of death, and may have been taken for confirmation of other findings. The high rate of concordance of histological and pathological findings in 23% of our reported cases suggests that many of these diagnoses are justified, although data have shown a relatively high incidence of discrepancy between macroscopic and histological diagnoses.9
The percentage of necropsies in our centre (33%) falls within the limits recommended by Royal College of Pathologists' guidelines,10
despite the fact that most necropsies in the UK are now performed for the coroner.11
At the same time, our study and others show consistent discrepancies between antemortem and postmortem diagnoses. Many authors believe that the necropsy and subsequent audit is the only valid means by which these inaccuracies can be remedied,2,12
because necropsy may confirm or refute clinical diagnoses as the final cause of death, with rates of up to 75% for previously undisclosed and clinically important findings.13
In previous studies, up to 23% of certificates have recorded only the mode of dying, with 55% incorrectly coded using the criteria of the International Classification of Diseases (ICD-IX) when used to classify mortality statistics.7
In studies of multiple causes of death, up to 54% were found to be inaccurate, with 79% of undiagnosed causes of death considered treatable,14
and 25–75% of death certificates recording more than one cause of death.7,15
“The relevance of these discrepancies at a population level is that they may also significantly alter mortality data, with subsequent inaccuracies in epidemiological statistics hiding potential associations between risk exposure and possible outcome”
There are several reasons for the discordance between our data and those of other reports. We have incorporated more than one cause of death for each patient where present on both the death certificate and at necropsy, whereas many previous studies take into account only one. Other studies have also included competing causes of death in their definition of error, whereas we believe that separate disease processes, each with an important impact, may have been disallowed. The very nature of the hospital necropsy is such that only the more difficult clinical cases are chosen and our data are derived from a tertiary referral centre where the most challenging cases will be managed. These may be situations where the clinical picture may not have been fully conclusive or where multiple disease processes are present, with difficulty in deciding the ultimate cause of death. Unfortunately, there is a widely acknowledged universal decline in the rate of necropsies,16
especially in the elderly, where there is a potentially higher discrepancy rate and therefore higher rate of undiagnosed conditions.17
The inclusion of an elderly inpatient population in our data will therefore have influenced these results because the clinical presentation may often be atypical, with the real cause of death being difficult to elicit.
Take home messages
- The overall sensitivity of the death certificate in predicting an individual cause of death was 0.47, with sensitivities ranging from 0.90 in the neurological system to 0.28 in the cardiovascular system, and the sensitivity for all malignant causes of death was 0.65
- No significant overall differences were noted in respiratory, gastrointestinal, malignant, and “other” systems when comparing causes of death on the death certificate with those at necropsy
- There is a substantial discrepancy between the diagnosis given on death certificates compared with that at hospital necropsy
- Thus, the declining rate of hospital “request” necropsies is a worrying and regrettable trend with important implications for mortality statistics, clinical audit, and clinical education
The discordance between this and other studies can also be partially explained by the limited clinical information the pathologist may possess at the time of the necropsy. This may be the result of a lack of meaningful communication between the clinician and pathologist, either before or at the conclusion of the necropsy. Further discrepancies may develop because of the constraints of death certification, where only those factors directly causing death are recorded by the clinician, so that not all the diseases of an individual are recorded. It follows from this that a lack of clinical information at the time of the necropsy, especially the timing and presence of multiple pathology, may make it difficult to decide which of these should be included within the real cause of death. Alternatively, in complex cases the notes may be voluminous and poorly sequenced, and without discussion of these cases between clinician and pathologist it is possible that the important issues may not be highlighted. The fact that a complex cause of death may be surmised in a two part form suggests inadequacies within the death certificate itself, and others have previously suggested that it should include diseases present at the time of death, rather than conditions leading directly to death, and that an underlying cause of death could be listed as “pending” until the clinicians have seen the results of the necropsy before completion of the certificate.18
The relevance of these discrepancies at a population level is that they may also significantly alter mortality data, with subsequent inaccuracies in epidemiological statistics hiding potential associations between risk exposure and possible outcome. Suggestions for improvements in data have been the immediate audit of data by the attending staff, completion of workshops by certifying doctors, and addenda to certificates to incorporate new findings.18–20
We also suggest that attendance at the necropsy by clinicians would further facilitate this process.
In conclusion, we have shown that inaccuracies are still common in the completion of the death certificate in the current hospital setting. It follows from this that the declining rate of hospital “request” necropsies is a worrying and regrettable trend with important implications for mortality statistics, clinical audit, and clinical education. The encouragement of meaningful communication between the clinician and the pathologist may help to redress this balance and also aid accurate recording of the cause of death.