Effect of minimally invasive autopsy and ethnic background on acceptance of clinical postmortem investigation in adults.

Objectives Autopsy rates worldwide have dropped significantly over the last five decades. Imaging based autopsies are increasingly used as alternatives to conventional autopsy (CA). The aim of this study was to investigate the effect of the introduction of minimally invasive autopsy, consisting of CT, MRI and tissue biopsies on the overall autopsy rate (of CA and minimally invasive autopsy) and the autopsy rate among different ethnicities. Methods We performed a prospective single center before-after study. The intervention was the introduction of minimally invasive autopsy as an alternative to CA. Minimally invasive autopsy consisted of MRI, CT, and CT-guided tissue biopsies. Autopsy rates over time and the effect of introducing minimally invasive autopsy were analyzed with a linear regression model. We performed a subgroup analysis comparing the autopsy rates of two groups: a group of western-European ethnicity versus a group of other ethnicities. Results Autopsy rates declined from 14.0% in 2010 to 8.3% in 2019. The linear regression model showed a significant effect of both time and availability of minimally invasive autopsy on the overall autopsy rate. The predicted autopsy rate in the model started at 15.1% in 2010 and dropped approximately 0.1% per month (β = -0.001, p < 0.001). Availability of minimally invasive autopsy increased the overall autopsy rate by 2.4% (β = 0.024, p < 0.001). The overall autopsy rate of people with an ethnic background other than western-European was significantly higher in years when minimally invasive autopsy was available compared to when it was not (22/176 = 12.5% vs. 81/1014 (8.0%), p = 0.049). Conclusions The introduction of the minimally invasive autopsy had a small, but significant effect on the overall autopsy rate. Furthermore, the minimally invasive autopsy appears to be more acceptable than CA among people with an ethnicity other than western-European.

are increasingly used as alternatives to conventional autopsy (CA). The aim of this study was to 20 investigate the effect of the introduction of minimally invasive autopsy, consisting of CT, MRI and tissue 21 biopsies on the total consent rate for postmortem diagnostics. 22

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We performed a prospective single center before-after study. The intervention was the introduction of 24 minimally invasive autopsy as an alternative to conventional autopsy. Minimally invasive autopsy 25 consisted of MRI, CT, and CT-guided tissue biopsies. Consent rates over time and the effect of 26 introducing minimally invasive autopsy were analyzed with a linear regression model. We performed a 27 subgroup analysis comparing the consent rates of two groups: a group of western-European ethnicity 28 versus a group of other ethnicities. 29

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Autopsy rates declined from 14.0% in 2010 to 8.3% in 2019. The linear regression model showed a 31 significant effect of both time and availability of minimally invasive autopsy on the consent rate. The 32 predicted acceptance rate in the model started at 15.1% in 2010 and dropped approximately 0.1% per 33 month (β = -0.001, p < 0.001). Availability of minimally invasive autopsy increased the acceptance rate by 34 2.4% (β = 0.024, p < 0.001). The overall post-mortem consent rate of people with an ethnic background 35 other than western-European was significantly higher in years when minimally invasive autopsy was 36 available compared to when it was not available (22/176=12.5% vs. 81/1014 (8.0%), p=0.049).

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The introduction of minimally invasive autopsy had a small, but significant effect on the overall consent 39 rates for postmortem investigations. Furthermore, the minimally invasive autopsy appears to be more 40 acceptable than conventional autopsy among people with an ethnicity other than western-European. 41

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Setting and design 65 This study was performed at the Erasmus University Medical Center in Rotterdam, the largest academic 66 hospital in the Netherlands. The design was a prospective before-after study whereby additional data 67 was collected retrospectively. The intervention was the introduction of minimally invasive autopsy as an 68 alternative to conventional autopsy. The study was approved by the Erasmus University Medical Center 69 Medical Ethical Committee (file number MEC-2011-055). The institutional review board approved the 70 study prior to data collection. All adult patients who had died in-hospital were included. 71

Autopsy procedures
72 Conventional autopsy and minimally invasive autopsy were both available from Monday to Friday. Only 73 1 minimally invasive autopsy per day was possible, due to limited scanner availability. When multiple 74 minimally invasive autopsy procedures were requested on the same day, requests would be processed 75 in the order they were received: if next-of-kin agreed, a procedure would be postponed until the next 76 available day. 77 Minimally invasive autopsy procedure 78 A minimally invasive autopsy consisted of MRI of the head and torso, full-body CT scan and CT-guided 79 biopsies of organs (heart, lungs, liver, kidneys and spleen) and additional biopsies of abnormal / 80 pathological lesions detected on imaging. The CT and MRI protocols are described in previous articles. 81 (8, 13-15) 82 Conventional autopsy procedure 83 The conventional autopsy was performed according to standard department protocol: the body was 84 opened with a Y-incision and the thoracic cavity opened with a rib-cutter. Organs were eviscerated by 85 the mortuary assistant and dissected by a resident in pathology, supervised by a certified pathologist. (8)  As a secondary outcome we investigated the motivations of next-of-kin for consenting to or refusing an 94 autopsy, and the motivations of doctors to not ask for permission. We distributed the questionnaires to 95 the doctors who were involved in the consent process, since they would be informed about the 96 motivations of next-of-kin when discussing the possibility of autopsy after a patient had passed away. 97 Questionnaires were distributed from September 2016 -December 2017. 98

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Because we expected that the autopsy rates were declining during the study period we performed a 100 linear regression analysis to calculate the effect of time and availability of minimally invasive autopsy on 101 consent rate. The independent variables were time in months since the start of the study and the 102 availability of minimally invasive autopsy as a standalone postmortem investigation.
We performed a subgroup analysis among people of western-European ethnicity versus people of other 104 ethnical backgrounds. We calculated the acceptance rates of both groups and performed an 105 independent T-test in order to test for significance. 106 To determine the ethnicity, we used a two-stage classification process. In the first stage, the predicted 107 probabilities of a supervised machine-learning algorithm were used to distinguish between 108 classifications with high and low certainty. For this stage, we used a random forest classifier (method 109 ranger in the R package caret). To train and test the classifier, we used data from a questionnaire in 110 which the next-of-kin were asked to provide the ethnic background of the deceased. (7, 16) The total set 111 consisted of 2,083 cases, which were split in a training set (80%) and a test set (20%). As features we 112 used character n-grams (with n = 2, 3, and 4) of the last names and, if available, of the first names. Each 113 case was labelled as having either a western-European or other ethnic background. Henceforth we will 114 refer to this latter group as 'other' ethnicities. The training set was used to develop the classifier; the 115 test set was only used for performance evaluation. Performance measures were the area under the 116 receiver operating characteristic curve (AUROC), negative predictive value (proportion of correctly 117 predicted Western-European cases), and positive predictive value (proportion of correctly predicted 118 cases of 'other' ethnicity). (17)(18)(19) In the second stage, the classifications with low certainty were 119 manually validated, in cases of doubt the Dutch surname database was consulted 120 (https://www.cbgfamilienamen.nl/nfb/). For the manual classification, the group allocation 121 (intervention vs. non-intervention) was unknown to the observer (IMW).   The next-of-kin had already consented to an organ donation procedure 9/69 (13%)

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Reasons of next-of-kin for giving or denying consent for postmortem diagnostics are listed in

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In this study we investigated if the introduction of a minimally invasive autopsy consisting of CT, MRI 282 and biopsies would lead to an increase in total combined consent rates for post-mortem investigations 283 (conventional autopsy and minimally invasive autopsy). We found that the introduction of minimally 284 invasive autopsy had a small, but significant effect on the combined consent rates for postmortem 285 investigations. Furthermore, the minimally invasive autopsy appears to be more acceptable than 286 conventional autopsy among people with an ethnicity other than western-European. 287