Method: We examined a series of 440 consecutive adult hospital necropsies performed at Addenbrooke's Hospital, without prior knowledge of the cause of death on the death certificate. The major causes of death at necropsy were subdivided on the basis of organ systems and subsequently compared with the cause of death stated on the death certificate.

Results: There were 448 stated causes of death on the death certificates, compared with 508 causes recorded at necropsy. 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.

We have elected to categorise each of the immediate and underlying causes of death given on the death certificate and compare them to those found at necropsy. We also attempt to analyse the diagnostic accuracy of the diagnosis given on the death certificate as a major cause of death by comparing it with its respective diagnosis at necropsy to establish a baseline for clinical performance and future audit.

Causes of death at necropsy were defined by the pathologist and these were divided into major organ systems with a category for systemic disease. A separate category of malignancy was assessed, with cases drawn from the previously stated organ systems.

The causes of death on the death certificate and at necropsy were compared and tabulated according to whether the clinical (death certificate) diagnosis was:

Sensitivity was calculated as the proportion of true positives divided by the sum of true positive and false negative diagnoses, and positive predictive value (PPV) as the number of true positives divided by true positives and false positives, respectively.⁶ We specifically charted individual causes of death where more than three cases of any cause were documented, although the overall sensitivity and PPV have taken into account all causes. Within the malignant category, specific information on the overdiagnosed category was gained retrospectively by studying the necropsy report itself. We evaluated the proportion of cases for which tissue was obtained for histology, how often this was formally reported, and the proportion of cases to which the histology was confirmatory of clinical or necropsy findings.

Of the 471 hospital necropsies, data were reviewed for 440 cases (93%), with the remainder excluded because of a lack of complete information. The male : female ratio was 1.1 : 1, with the mean age at necropsy being 78.2 years and a range of 28 to 100 years. In many cases, more than one cause of death was diagnosed, with 508 found at necropsy compared with 448 on the death certificate. Table 1​1 lists the major individual causes of death in cases of more than three causes and table 2​2 details the sensitivity and PPVs of the individual organ systems in predicting the accurate cause of death. Table 3​3 shows total causes of death on the certificate and at necropsy for organ systems, with a separate category for malignancy.

The overall sensitivity and PPV of the death certificate, for any individual cause, were 0.47 and 0.54, respectively.

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

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.

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.