The clinical performance of the M4 decision support model to triage women with a pregnancy of unknown location as at low or high risk of complications
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
Study question: What are the adverse outcomes associated with using the M4 model in everyday clinical practice for women with pregnancy
of unknown location (PUL)?
Summary answer: There were 17/835 (2.0%) adverse events and no serious adverse events associated with the performance of the M4
model in clinical practice.
What is known already: The M4 model has previously been shown to stratify women classified as a PUL as at low or high risk of
complications with a good level of test performance. The triage performance of the M4 model is better than single measurements of serum progesterone
or the hCG ratio (serum hCG at 48 h/hCG at presentation).
Study design, size, duration: A prospective multi-centre cohort study of 1022 women with a PUL carried out between August
2012 and December 2013 across 2 university teaching hospitals and 1 district general hospital.
Participants/materials, setting, methods: All women presenting with a PUL to the early pregnancy units of the three hospitals
were recruited. The final outcome for PUL was either a failed PUL (FPUL), intrauterine pregnancy (IUP) or ectopic pregnancy (EP) (including
persistent PUL (PPUL)), with EP and PPUL considered high-risk PUL. Their hCG results at 0 and 48 h were entered into the M4 model algorithm.
If the risk of EP was ≥5%, the PUL was predicted to be high-risk and the participant was asked to re-attend 48 h later for a repeat hCG and transvaginal
ultrasound scan by a senior clinician. If the PUL was classified as ‘low risk, likely failed PUL’, the participant was asked to perform a urinary pregnancy test
2 weeks later. If the PUL was classified as ‘low risk, likely intrauterine’, the participant was scheduled for a repeat scan in 1 week. Deviations from the
management protocol were recorded as either an ‘unscheduled visit (participant reason)’, ‘unscheduled visit (clinician reason)’ or ‘differencesin timing
(blood test/ultrasound)’. Adverse events were assessed using definitions outlined in the UK Good Clinical Practice Guidelines’ document.
Main results and the role of chance: A total of 835 (82%) women classified as a PUL were managed according to the M4
model (9 met the exclusion criteria, 69 were lost to follow-up, 109 had no hCG result at 48 h). Of these, 443 (53%) had a final outcome of
FPUL, 298 (36%) an IUP and 94 (11%) an EP. The M4 model predicted 70% (585/835) PUL as low risk, of which 568 (97%) were confirmed
as FPUL or IUP. Of the 17 EP and PPUL misclassified as low risk, 5 had expectant management, 7 medical management with methotrexate
and 5 surgical intervention.
of unknown location (PUL)?
Summary answer: There were 17/835 (2.0%) adverse events and no serious adverse events associated with the performance of the M4
model in clinical practice.
What is known already: The M4 model has previously been shown to stratify women classified as a PUL as at low or high risk of
complications with a good level of test performance. The triage performance of the M4 model is better than single measurements of serum progesterone
or the hCG ratio (serum hCG at 48 h/hCG at presentation).
Study design, size, duration: A prospective multi-centre cohort study of 1022 women with a PUL carried out between August
2012 and December 2013 across 2 university teaching hospitals and 1 district general hospital.
Participants/materials, setting, methods: All women presenting with a PUL to the early pregnancy units of the three hospitals
were recruited. The final outcome for PUL was either a failed PUL (FPUL), intrauterine pregnancy (IUP) or ectopic pregnancy (EP) (including
persistent PUL (PPUL)), with EP and PPUL considered high-risk PUL. Their hCG results at 0 and 48 h were entered into the M4 model algorithm.
If the risk of EP was ≥5%, the PUL was predicted to be high-risk and the participant was asked to re-attend 48 h later for a repeat hCG and transvaginal
ultrasound scan by a senior clinician. If the PUL was classified as ‘low risk, likely failed PUL’, the participant was asked to perform a urinary pregnancy test
2 weeks later. If the PUL was classified as ‘low risk, likely intrauterine’, the participant was scheduled for a repeat scan in 1 week. Deviations from the
management protocol were recorded as either an ‘unscheduled visit (participant reason)’, ‘unscheduled visit (clinician reason)’ or ‘differencesin timing
(blood test/ultrasound)’. Adverse events were assessed using definitions outlined in the UK Good Clinical Practice Guidelines’ document.
Main results and the role of chance: A total of 835 (82%) women classified as a PUL were managed according to the M4
model (9 met the exclusion criteria, 69 were lost to follow-up, 109 had no hCG result at 48 h). Of these, 443 (53%) had a final outcome of
FPUL, 298 (36%) an IUP and 94 (11%) an EP. The M4 model predicted 70% (585/835) PUL as low risk, of which 568 (97%) were confirmed
as FPUL or IUP. Of the 17 EP and PPUL misclassified as low risk, 5 had expectant management, 7 medical management with methotrexate
and 5 surgical intervention.
Date Issued
2016-05-10
Date Acceptance
2016-04-07
Citation
Human Reproduction, 2016, 31 (7), pp.1425-1435
ISSN
0268-1161
Publisher
Oxford University Press
Start Page
1425
End Page
1435
Journal / Book Title
Human Reproduction
Volume
31
Issue
7
Copyright Statement
© 2016 The Author. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. This is a pre-copy-editing, author-produced version of an article accepted for publication in Human Reproduction following peer review. The definitive publisher-authenticated versionS. Bobdiwala, S. Guha, B. Van Calster, F. Ayim, N. Mitchell-Jones, M. Al-Memar, H. Mitchell, C. Stalder, C. Bottomley, A. Kothari, D. Timmerman, T. Bourne; The clinical performance of the M4 decision support model to triage women with a pregnancy of unknown location as at low or high risk of complications, Human Reproduction, Volume 31, Issue 7, 1 July 2016, Pages 1425–1435, is available online at: https://dx.doi.org/10.1093/humrep/dew105
Sponsor
Chelsea & Westminster Hospital NHS Foundation Trust
Imperial College Healthcare NHS Trust- BRC Funding
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000383242900009&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
RDIP0033 RAMP
RDD03 79560
Subjects
Science & Technology
Life Sciences & Biomedicine
Obstetrics & Gynecology
Reproductive Biology
ectopic pregnancy
miscarriage
pregnancy of unknown location
decision support techniques
ultrasonography
triage
adverse events
HUMAN CHORIONIC-GONADOTROPIN
ECTOPIC PREGNANCY
EXPECTANT MANAGEMENT
SERUM HCG
CONFIDENCE-INTERVALS
LOGISTIC-REGRESSION
FAILING PREGNANCIES
PROGESTERONE
INFORMATION
PREDICTION
16 Studies In Human Society
11 Medical And Health Sciences
Obstetrics & Reproductive Medicine
Publication Status
Published