Hospital autopsy audit: discordant primary clinical diagnoses are found in 20% of cases in a reducing autopsy case load. Selection bias or significant findings?

Abstract

The post-mortem examination is an effective tool that provides insight into a patient’s medical care and assists in auditing clinical decision making. Thus, post-mortems have the potential to improve quality of care, educate the medical community, ensure accurate epidemiological health statistics and assist bereft relatives in coming to terms with end of life issues. The post-mortem examination, also known as autopsy or necropsy, became an influential medical procedure in the Middle Ages that significantly advanced our understanding of human disease. Standardised by Virchow, ‘the dissection of the dead body to determine, through direct observation, the cause of death or the nature of the disease’ was common place and an integral part of medical curricula until the mid-twentieth century. However, Australian and international hospital autopsy rates have declined in recent decades, due in part to advances in diagnostic technologies and possibly an unfamiliarity of their value among doctors with little exposure to autopsies. Comprehensive Australian data from the mid-2000s reported that the nation’s hospital autopsy rate declined from 21% to 12% over a 10 year period. Similar observations have been made elsewhere, including in the USA, UK, Europe, Hong Kong and China. Despite this decline, discrepancies between clinical and autopsy diagnoses continue to be found in limited studies published over the last 15 years. A meta-analysis of autopsy studies by Roulson et al. found that discrepancies in major diagnoses and potentially treatable conditions occurred at rates of 15–41% and 10–44%, respectively. Therefore, many authors contend that the autopsy remains a relevant and valuable tool with the potential to inform and educate the medical community. Advances in diagnostic technologies are understandably a factor that has contributed to the decline. Other reasons include unfavourable public attitudes, restrictions placed on the extent of examination by next-of-kin, lack of resources, poor training of medical staff in autopsy consent, time-consuming consent processes and unfamiliarity among the medical community of the value of autopsy. As far as the authors are aware, hospital autopsy data have not been published from Australian sources for a decade. Therefore, we undertook an audit of non-coronial autopsies between August 2011 and August 2013 at a major Australian tertiary centre for trauma and heart-lung transplantation to examine concordance of clinical and autopsy findings. Using retrospective data from death certificates, hospital records and autopsy reports, the clinical cause of death (COD) and major co-morbid diagnoses were compared with autopsy findings for all hospital post-mortems performed across a 2 year period (August 2011–August 2013). Cases referred to the coroner were excluded from the study. In every case a death certificate was completed by the clinical team prior to the autopsy being conducted. The type of autopsy (partial or full) was recorded for each case and a comprehensive microscopic examination was carried out where possible within the limitations of consent. Based on the autopsy findings, the death certificate and clinical diagnoses were assessed as either correct or discordant. Significant missed diagnoses that may have impacted clinical care were also noted. Minor discrepancies that were considered not to have impacted on the patient’s acute episode of care were excluded from the final results. Thus, a discordant autopsy was one where the autopsy findings were considered a substantially different pathological process contributing to death when compared to the death certificate and major ante-mortem diagnoses. The findings were then rated in accord with past studies. Of 1298 hospital deaths between August 2011 and August 2013, 86 patients were referred for autopsies (autopsy rate 6.6%). Full autopsies accounted for 70% (60/86) and partial for 30% (26/86). Ages ranged from 14 to 91 (mean age 61). Male cases accounted for 52% (45/86) and organ transplant recipients for 29% (25/86). Cause of death was assessable at post-mortem in all but one partial autopsy. In the latter case the COD (multiple myeloma) was unable to be fully evaluated since the next-of-kin consented only to examination of the heart, in which amyloid of the myocardial vessels was diagnosed. Of conclusive autopsies, correct diagnoses were made in 80% (68/85) while discordant diagnoses accounted for 20% (17/85). The most common correct causes of death were infections in 20% (17/85), respiratory aetiologies in 20% (17/85) and cardiovascular conditions in 16% (14/85) (Table 1). The most common missed COD was an infective aetiology (frequently fungal) occurring in 9% of cases (8/85), of which half were transplant patients. Respiratory and cardiovascular causes each accounted for 4% of cases (3/85). In 12% (10/85) the discordance was a major change from one body system to another (Table 2). Examples of discordant diagnoses are shown in Fig. 1–4. Pathology (October 2015) 47(6), pp. 499–502