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The test characteristics of head circumference measurements for pathology associated with head enlargement: a
Carrie Daymont1, Moira Zabel, Chris Feudtner
1Department of Pediatrics and Child Health, The University of Manitoba, Winnipeg, Manitoba, Canada. cdaymont@mich.ca
Insights
Common head circumference (HC) percentile thresholds show low sensitivity and low positive predictive value for identifying head enlargement pathology in children. These criteria are insufficient for early diagnosis in primary care settings.
Area of Science:
- Pediatric Medicine
- Medical Diagnostics
- Public Health
Background:
- Head circumference (HC) measurement criteria for identifying head enlargement pathology in primary care lack established test characteristics.
- Early detection of intracranial expansive conditions (IEC) and macrocephaly-associated metabolic and genetic conditions (MGCM) is crucial.
Purpose of the Study:
- To evaluate the diagnostic accuracy of various head circumference (HC) percentile thresholds for identifying previously undetected pathology in children.
- To assess the sensitivity, positive predictive value (PPV), and likelihood ratios (LR+) of different HC criteria.
Main Methods:
- Retrospective review of electronic patient records for children aged 3 days to 3 years.
- Identification of children with new diagnoses of IEC or MGCM.
- Testing HC percentile thresholds: ever above 95th, 97th, or 99.6th percentile; crossing 2, 4, or 6 increasing major percentile lines.
- Utilized CDC, WHO, and primary care network (PCN) growth curves.
Main Results:
- Out of 74,428 children, 85 (0.11%) had new diagnoses of IEC or MGCM.
- The 99.6th percentile (PCN curve) showed the highest PPV (1.8%) but low sensitivity (15%).
- Commonly used thresholds (95th, 97th percentiles) demonstrated low PPV (0.3%-0.6%) and moderate sensitivity (34%-55%).
- Crossing percentile lines showed higher sensitivity (31%-60%) but very low PPV (0.1%-0.2%).
Conclusions:
- Standard head circumference percentile thresholds exhibit poor performance in detecting significant head enlargement pathology in primary care.
- Current HC measurement criteria are inadequate for the reliable identification of children requiring further investigation for serious conditions.
Background:
The test characteristics of head circumference (HC) measurement percentile criteria for the identification of previously undetected pathology associated with head enlargement in primary care are unknown.
Methods:
Electronic patient records were reviewed to identify children age 3 days to 3 years with new diagnoses of intracranial expansive conditions (IEC) and metabolic and genetic conditions associated with macrocephaly (MGCM). We tested the following HC percentile threshold criteria: ever above the 95th, 97th, or 99.6th percentile and ever crossing 2, 4, or 6 increasing major percentile lines. The Centers for Disease Control and World Health Organization growth curves were used, as well as the primary care network (PCN) curves previously derived from this cohort.
Results:
Among 74,428 subjects, 85 (0.11%) had a new diagnosis of IEC (n = 56) or MGCM (n = 29), and between these 2 groups, 24 received intervention. The 99.6th percentile of the PCN curve was the only threshold with a PPV over 1% (PPV 1.8%); the sensitivity of this threshold was only 15%. Test characteristics for the 95th percentiles were: sensitivity (CDC: 46%; WHO: 55%; PCN: 40%), positive predictive value (PPV: CDC: 0.3%; WHO: 0.3%; PCN: 0.4%), and likelihood ratios positive (LR+: CDC: 2.8; WHO: 2.2; PCN: 3.9). Test characteristics for the 97th percentiles were: sensitivity (CDC: 40%; WHO: 48%; PCN: 34%), PPV (CDC: 0.4%; WHO: 0.3%; PCN: 0.6%), and LR+ (CDC: 3.6; WHO: 2.7; PCN: 5.6). Test characteristics for crossing 2 increasing major percentile lines were: sensitivity (CDC: 60%; WHO: 40%; PCN: 31%), PPV (CDC: 0.2%; WHO: 0.1%; PCN: 0.2%), and LR+ (CDC: 1.3; WHO: 1.1; PCN: 1.5).
Conclusions:
Commonly used HC percentile thresholds had low sensitivity and low positive predictive value for diagnosing new pathology associated with head enlargement in children in a primary care network.
