Does a prediction model for pregnancy of unknown location developed in the UK validate on a US population?

Barnhart, Kurt T.; Sammel, Mary D.; Appleby, Dina; Rausch, Mary; Molinaro, T.A.; Calster, Ben Van; Kirk, E.; Condous, G.; Huffel, Sabine Van; Timmerman, Dirk; Bourne, Tom

doi:10.1093/humrep/deq217

Cited by 33 publications

(40 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both these factors would add to the calculated risk of EP by protocol M4. Interestingly, contrary to EPs in our cohort and a UK population, the hCG levels were twice as high as compared with a US population where the M4 model was evaluated (Barnhart et al, 2010) and only identified 49% of the EPs.…”

Section: Discussioncontrasting

confidence: 83%

“…This limitation together with the study's retrospective nature emphasises the need of prospective studies. The use of estimated 48 h hCG values in the present study could also ultimately have had an impact on the performance of the protocols, although the original curves for a viable IUP were derived from the use of log lineartransformed hCG values and have subsequently been used in other studies (Barnhart et al, 2004(Barnhart et al, , 2010Zee et al, 2013). Strengths of the study are the relatively large sample size with a high prevalence of EPs, and the setting that reflected real clinical practice.…”

Section: Discussionmentioning

confidence: 99%

“…Since the second hCG sample was taken at various times between 24 and 72 h, an estimated value was calculated for those not having an exact 48-h value. As in previous studies (Barnhart et al, 2010;Zee et al 2013), we assumed a linear function of log-transformed values between the baseline (0 h) and the second measurement for each patient. A second value beyond 48 h was interpolated according to this line, while a second value within 48 h was extrapolated according to the line to obtain an estimated 48-h hCG value.…”

Section: Protocolsmentioning

confidence: 99%

“…To date several protocols for PUL management have been proposed but there have been few comparative studies. The prevalence of EPs among PULs have been reported to be between 6 and 17% Bignardi et al, 2008;Barnhart et al, 2010;Morse et al, 2012), which reflects the frequency of EPs missed on the initial transvaginal ultrasonography (TVS). In order to identify those at risk of being an EP, interpretation of the rate of change in repeated serum human chorionic gonadotropin (hCG) measurements between 0 and 48 hours (h), until a final location can be established, is a common PUL practice.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Classification of pregnancies of unknown location according to four different hCG-based protocols

Fistouris

Bergh

2016

Hum. Reprod.

View full text Add to dashboard Cite

STUDY QUESTION: How do four protocols based on serial human chorionic gonadotropin (hCG) measurements perform when classifying pregnancies of unknown location (PULs) as low or high risk of being an ectopic pregnancy (EP)?SUMMARY ANSWER: The use of cut-offs in hCG level changes published by NICE, and a logistic regression model, M4, correctly classify more PULs as high risk, compared with two other protocols.WHAT IS KNOWN ALREADY: A logistic regression model, M4, based on the mean of two consecutive hCG values and the hCG ratio (hCG 48 h/hCG 0 h) that classify PULs into low-and high-risk groups for triage purposes, identifies more EPs than a protocol using the cutoffs between a 13% decline and a 66% rise in hCG levels over 48 h. STUDY DESIGN, SIZE, DURATION:A retrospective comparative study of four different hCG-based protocols classifying PULs as low or high risk of being an EP was performed at a gynaecological emergency unit over 3 years. PARTICIPANTS/MATERIALS, SETTING, METHOD:We identified 915 women with a PUL. Initial transvaginal ultrasonography (TVS) findings categorised 187 of the PULs as probable intrauterine pregnancies (IUPs) and 16 as probable EPs. The rate of change in hCG levels over 48 h was calculated for each patient and subjected to three different hCG threshold intervals and a logistic regression model for outcome prediction. Each PUL was subsequently dichotomised to either low-risk (i.e. failed PUL/IUP) or high-risk (i.e. EP) classification, which allowed us to compare the diagnostic performance. In 'Protocol A', a PUL was classified as low risk if >13% hCG level decline or >66% hCG level rise was achieved; otherwise, the PUL was classified as high risk of being an EP. 'Protocol B' classified a PUL as low or high risk using cut-offs of 35-50% declining hCG levels and of 53% rising hCG levels. Similarly, 'Protocol C' used hCG level cut-offs published by NICE, 50% for declining hCG levels and 63% for rising hCG levels. Finally, if a logistic regression model 'Protocol M4' calculated a ≥5% risk of the PUL being an EP, it was classified as high risk, and otherwise the PUL was classified as low risk. When the time interval between two hCG measurements failed to meet an exact 48 h, extrapolation and interpolation of hCG values was made, using log linear transformation.MAIN RESULTS AND THE ROLE OF CHANCE: Protocols A, B, C and M4 classified 73, 66, 55 and 56% of PULs as low risk. The sensitivity for protocols A, B, C and M4 was 68% (95% confidence interval (CI) 61-75%), 81% (74-86%), 87% (82-92%) and 88% (83-93%), respectively. The specificity was 82% (80-85%), 77% (74-80%), 66% (62-69%) and 67% (63-70%) for protocols A, B, C and M4, respectively. All comparisons of sensitivity and specificity between the protocols were statistically significant except for protocol C versus protocol M4. In protocol C, 87% (66-97%) of misclassified EPs had rising hCG levels, compared with 19% (6-41%) for protocol M4 (P < 0.01). In a secondary analysis excluding probable IUPs and probable EPs, the results for 712 PULs ...

show abstract

Section: Discussioncontrasting

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Protocolsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Classification of pregnancies of unknown location according to four different hCG-based protocols

Fistouris

Bergh

2016

Hum. Reprod.

View full text Add to dashboard Cite

show abstract

“…Prediction models may lose excellent test characteristics when applied externally, or may need to be amended or updated to maintain accuracy (20). The purpose of this study is to compare observed hCG curves to expected curves in a diverse set of patients with symptomatic early pregnancy and a PUL in order to predict outcome.…”

Section: Introductionmentioning

confidence: 99%

Performance of human chorionic gonadotropin curves in women at risk for ectopic pregnancy: exceptions to the rules

Morse

Sammel

Shaunik

et al. 2012

Fertility and Sterility

View full text Add to dashboard Cite

Objective To investigate the accuracy of serial hCG to predict outcome of a pregnancy of unknown location in an ethnically and geographically diverse setting. Design Multi-site cohort study Setting University hospital Patients Women with a pregnancy of unknown location Interventions None Main outcome measures Patients were followed until diagnosed with ectopic pregnancy (EP), intrauterine pregnancy (IUP), or miscarriage. To predict outcome, observed hCG was compared to recommended thresholds to assess deviation from defined normal curves. Predicted outcome was compared to standard of care. Sensitivity, specificity, predictive value, and accuracy were calculated, stratified by diagnosis. Results The final diagnosis 1,005 patients included 179 EPs, 259 IUPs, and 567 miscarriages. The optimal balance in sensitivity and specificity used the minimal expected two-day rise in hCG of 35%, and the minimal two-day decline in hCG of 36–47% (depending on the level) achieving 83.2% sensitivity, 70.8% specificity to predict EP. However 16.8% of EPs and 7.7% of IUPs would be misclassified solely using serial hCGs. Consideration of a third hCG and early ultrasound decreased IUP misclassification to 2.7%. Conclusion Solely using serial hCG values can result in misclassification. Clinical judgment should trump prediction rules and continued surveillance with a third hCG may be prudent, especially when initial values are low or when values are near suggested thresholds.

show abstract

Conventional and modern markers of pregnancy of unknown location: Update and narrative review

Hou,

Liang,

Zeng

et al. 2024

Intl J Gynecology & Obste

View full text Add to dashboard Cite

Pregnancy of unknown location (PUL) is a temporary pathologic or physiologic phenomenon of early pregnancy that requires follow up to determine the final pregnancy outcome. Evidence indicated that PUL patients suffer a remarkably higher rate of adverse pregnancy outcomes, represented by ectopic gestation and early pregnancy loss, than the general population. In the past few decades, discussion about PUL has never stopped, and a variety of markers have been widely investigated for the early and accurate evaluation of PUL, including serum biomarkers, ultrasound imaging features, multivariate analysis, and the diagnosis of ectopic pregnancy based on risk stratification. So far, machine learning (ML) methods represented by M4 and M6 logistic regression have gained a level of recognition and are continually improving. Nevertheless, the heterogeneity of PUL markers, mainly caused by the limited sample size, the differences in population and technical maturity, etc., have hampered the management of PUL. With the advancement of multidisciplinary integration and cutting‐edge technologies (e.g. artificial intelligence, prediction model development, and telemedicine), novel markers, and strategies for the management of PUL are expected to be developed. In this review, we summarize both conventional and novel markers (represented by artificial intelligence) for PUL assessment and management, investigate their advancements, limitations and challenges, and propose insights on future research direction and clinical application.

show abstract

Does a prediction model for pregnancy of unknown location developed in the UK validate on a US population?

Cited by 33 publications

References 19 publications

Classification of pregnancies of unknown location according to four different hCG-based protocols

Classification of pregnancies of unknown location according to four different hCG-based protocols

Performance of human chorionic gonadotropin curves in women at risk for ectopic pregnancy: exceptions to the rules

Conventional and modern markers of pregnancy of unknown location: Update and narrative review

Contact Info

Product

Resources

About