Misclassification in defining and diagnosing microcephaly

Kalmin, Mariah M; Gower, Emily W.; Stringer, Elizabeth M.; Bowman, Natalie M.; McQuade, Elizabeth T Rogawski; Westreich, Daniel

doi:10.1111/ppe.12561

Cited by 8 publications

(7 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Simulations indicate that surveillance data are generally insufficient to estimate the gestational-age-specific risk of microcephaly, especially given possible changes in reporting that might be caused by an epidemic [ 27 , 28 ]. Birth defect surveillance data from Colombia did indicate a peak in microcephaly (based on diagnosis code) corresponding with the Zika epidemic; however, very large numbers would be needed to detect the observed differences in prevalence (13 cases per 10,000 livebirths during the outbreak, vs. 8 per 10,000 before and 11 per 10,000 after) [ 29 ].…”

Section: Discussionmentioning

confidence: 99%

“…Birth defect surveillance data from Colombia did indicate a peak in microcephaly (based on diagnosis code) corresponding with the Zika epidemic; however, very large numbers would be needed to detect the observed differences in prevalence (13 cases per 10,000 livebirths during the outbreak, vs. 8 per 10,000 before and 11 per 10,000 after) [ 29 ]. In addition, percentile-based definitions produce a high degree of false positives when compared to truly pathological cases; simulation studies under realistic scenarios estimate <5% positive predictive value [ 27 ].…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Measurement of Head Circumference: Implications for Microcephaly Surveillance in Zika-Affected Areas

et al. 2020

View full text Add to dashboard Cite

Worldwide recognition of the Zika virus outbreak in the Americas was triggered by an unexplained increase in the frequency of microcephaly. While severe microcephaly is readily identifiable at birth, diagnosing less severe cases requires comparison of head circumference (HC) measurement to a growth chart. We examine measured values of HC and digit preference in those values, and, by extension, the prevalence of microcephaly at birth in two data sources: a research study in Honduras and routine surveillance data in Uruguay. The Zika in Pregnancy in Honduras study enrolled pregnant women prenatally and followed them until delivery. Head circumference was measured with insertion tapes (SECA 212), and instructions including consistent placement of the tape and a request to record HC to the millimeter were posted where newborns were examined. Three indicators of microcephaly were calculated: (1) HC more than 2 standard deviations (SD) below the mean, (2) HC more than 3 SD below the mean (referred to as “severe microcephaly”) and (3) HC less than the 3rd percentile for sex and gestational age, using the INTERGROWTH-21st growth standards. We compared these results from those from a previous analysis of surveillance HC data from the Uruguay Perinatal Information System (Sistema Informático Perinatal (SIP). Valid data on HC were available on 579 infants, 578 with gestational age data. Nine babies (1.56%, 95% CI 0.71–2.93) had HC < 2SD, including two (0.35%, 95% CI 0.04–1.24) with HC < 3SD, and 11 (1.9%, 95% CI, 0.79–3.02) were below the 3rd percentile. The distribution of HC showed strong digit preference: 72% of measures were to the whole centimeter (cm) and 19% to the half-cm. Training and use of insertion tapes had little effect on digit preference, nor were overall HC curves sufficient to detect an increase in microcephaly during the Zika epidemic in Honduras. When microcephaly prevalence needs to be carefully analyzed, such as during the Zika epidemic, researchers may need to interpret HC data with caution.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Measurement of Head Circumference: Implications for Microcephaly Surveillance in Zika-Affected Areas

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Given the data source, the extent to which we can draw clinically relevant conclusions is limited, but it seems likely that any meaningful assessment will require more than a single measurement, which can at best serve as a screening tool. A recent simulation study suggests that cut-off-based definitions have very poor positive predictive values 28. The CDC has provided guidelines recommending a comprehensive physical examination, age-appropriate vision screening, developmental monitoring, hearing screening and neuroimaging when head circumference measurement suggests microcephaly, which may assist in defining the clinical case definitions for Zika-related or other severe birth defects 29.…”

Section: Discussionmentioning

confidence: 99%

Measurement error, microcephaly prevalence and implications for Zika: an analysis of Uruguay perinatal data

Harville

Buekens

Cafferata³

et al. 2019

Arch Dis Child

View full text Add to dashboard Cite

Background and objectiveThe Zika virus outbreak has drawn attention to microcephaly, whose definition is based on head circumference measuring below a percentile or number of SDs below the mean. The objective of this analysis was to assess how differences in measurement precision might affect prevalence and trends of microcephaly.MethodsData from all births in Uruguay during 2010–2015 were obtained from the Perinatal Information System. The prevalence of births with microcephaly was calculated based on head circumference measurement at birth applying the INTERGROWTH-21st standards for sex and gestational age, and compared by method of ascertaining gestational age.ResultsRounding and digit preference was observed: 74% of head circumference measurements were reported as a whole centimetre value. The prevalence of births varied substantially by the criterion used to define microcephaly (<3 SD, <2 SD, <3rd percentile for gestational age) and could be halved or doubled based on adding or subtracting a half-centimetre from all reported head circumference measurements. If 4 days were added to gestational age calculations, rather than using completed gestational weeks (without days) for gestational age reporting, the prevalence was 1.7–2 times higher.DiscussionRounding in measurement of head circumference and reporting preferences of gestational age may have contributed to a lower prevalence of microcephaly than expected in this population. Differences in head circumference measurement protocols and gestational age dating have the potential to affect the prevalence of babies reported with microcephaly, and this limitation should be acknowledged when interpreting head circumference data collected for surveillance.

show abstract

“…The definition of microcephaly varies from fetus to child [49]. It is defined as a fetal or newborn head circumference (HC) below the third percentile or, at least, two standard deviations (SDs) below the mean for sex, age, and ethnicity [50]. Severe microcephaly is defined as a HC below the parameters mentioned above [51].…”

Section: Microcephalymentioning

confidence: 99%

Congenital Zika Virus Infection: a Review with Emphasis on the Spectrum of Brain Abnormalities

Vhp

Aragão

Pinho

et al. 2020

Curr Neurol Neurosci Rep

View full text Add to dashboard Cite

Purpose of Review In 2016, the World Health Organization declared the Zika virus (ZIKV) outbreak a Public Health Emergency of International Concern following a cluster of associated neurological disorders and neonatal malformations. Our aim is to review the clinical and neuroimaging findings seen in congenital Zika syndrome. Recent Findings ZIKV injures neural progenitor cells in the hippocampus, a brain region important for learning, memory, cognition, and emotion/stress response. Positron emission tomography has revealed global neuroinflammation in ZIKV infection in animal models. Summary Congenital Zika syndrome is associated with a spectrum of brain abnormalities, including microcephaly, parenchymal calcifications, malformations of cortical development and defective neuronal migration, corpus callosum abnormalities, ventriculomegaly, and brainstem and cerebellar abnormalities.

show abstract

Misclassification in defining and diagnosing microcephaly

Cited by 8 publications

References 18 publications

Measurement of Head Circumference: Implications for Microcephaly Surveillance in Zika-Affected Areas

Measurement of Head Circumference: Implications for Microcephaly Surveillance in Zika-Affected Areas

Measurement error, microcephaly prevalence and implications for Zika: an analysis of Uruguay perinatal data

Congenital Zika Virus Infection: a Review with Emphasis on the Spectrum of Brain Abnormalities

Contact Info

Product

Resources

About