Report and Estimated Defect Prevalence Estimates (per 10,000 live births)

Defect	Reports	Report Prevalence (95%CI)	PPV	NPV	Estimated Defects	Defect Prevalence (95%CI)
Cardiovascular
Aortic valve stenosis	13	2.3 (1.2,3.9)				NA
Atrial septal defect	973	171.0 (160.4,182.1)				NA
Atrioventricular septal defect	29	5.1 (3.4,7.3)				NA
Coarctation of the aorta	31	5.4 (3.7,7.7)				NA
Common truncus	14	2.5 (1.3,4.1)				NA
Double outlet right ventricle	11	1.9 (1.0,3.5)				NA
Ebstein anomaly	-	-				NA
Hypoplastic left heart syndrome	9	1.6 (0.7,3.0)				NA
Interrupted aortic arch	44	7.7 (5.6,10.4)				NA
Pulmonary valve atresia and stenosis	68	12.0 (9.3,15.2)				NA
Single ventricle	13	2.3 (1.2,3.9)				NA
Teratology of fallot	34	6.0 (4.1,8.4)				NA
Total anomalous pulmonary venous connection	6	1.1 (0.4,2.3)				NA
Transposition of the great arteries	23	4.0 (2.6,6.1)				NA
Tricuspid valve atresia and stenosis	-	-				NA
Ventricular septal defect	582	102.3 (94.2,111.0)				NA
Central Nervous System
Anencephalus	7	1.2 (0.5,2.5)	0.3929	1.0000	2.8	0.5 (0.1,1.3)
Spina bifida without anencephalus	25	4.4 (2.8,6.5)	0.5946	0.9999	18.4	3.2 (2.0,5.0)
Encephalocele	11	1.9 (1.0,3.5)	0.3778	1.0000	4.5	0.8 (0.3,1.8)
Holoprosencephaly	83	14.6 (11.6,18.1)				NA
Chromosomal
Deletion 22 q11	10	1.8 (0.8,3.2)				NA
Trisomy 13	-	-	0.5000	1.0000	1.5	-
Trisomy 18	14	2.5 (1.3,4.1)	0.5833	1.0000	8.2	1.4 (0.7,2.8)
Trisomy 21 (Down syndrome)	87	15.3 (12.2,18.9)	0.8182	0.9999	76.7	13.5 (10.7,16.7)
Turner syndrome*	9	3.2 (1.5,6.2)				NA
Ear
Anotia / microtia	23	4.0 (2.6,6.1)				NA
Eye
Anophthalmia / microphthalmia	-	-				NA
Congenital cataract	26	4.6 (3.0,6.7)				NA
Gastrointestinal
Biliary atresia	-	-				NA
Esophageal atresia / tracheoesophageal fistula	15	2.6 (1.5,4.3)				NA
Rectal and large intestinal atresia / stenosis	46	8.1 (5.9,10.8)				NA
Small intestinal atresia / stenosis	33	5.8 (4.0,8.1)				NA
Genitourinary
Bladder exstrophy	-	-				NA
Cloacal exstrophy	-	-				NA
Congenital posterior urethral valves	43	7.6 (5.5,10.2)				NA
Hypospadias**	334	114.4 (102.5,127.4)	0.8618	0.9996	298.0	102.1 (90.8,114.0)
Renal agenesis / hypoplasia	53	9.3 (7.0,12.2)				NA
Musculoskeletal
Clubfoot	199	35.0 (30.3,40.2)				NA
Craniosynostosis	24	4.2 (2.7,6.3)				NA
Diaphragmatic hernia	24	4.2 (2.7,6.3)	0.7083	0.9999	20.0	3.5 (2.1,5.2)
Gastroschisis	47	8.3 (6.1,11.0)	0.6174	1.0000	31.6	5.6 (3.8,7.7)
Limb deficiencies	52	9.1 (6.8,12.0)				NA
Omphalocele	89	15.6 (12.6,19.2)	0.1856	1.0000	16.7	2.9 (1.7,4.6)
Orofacial
Choanal atresia	16	2.8 (1.6,4.6)				NA
Cleft lip with celft palate***	70	12.3 (6.7, 20.7)	0.6600	1.0000	46.9	16.14 (9.96, 24.82)
Cleft lip alone***	68	12.0 (6.7 19.6)	0.3913	1.0000	28.2	5.52 (2.4, 11.28)
Cleft palate alone***	116	20.4 (13.6, 30.4)	0.5610	0.9998	77.5	14.04 (8.34, 22.22)
Ref: NA = Information not available as of publication; '-' = supressed for cell counts <6; 95% CI = 95% Confidence Interval; g = grams, PPV = Positive Predictive Value; NPV = Negative Predictive value *per 10,000 live female births **per 10,000 live male births ***All cleft condition defect estimates include additional adjustments (not displayed here) for intra-conditional misclassification (i.e. individuals reported for the wrong, or multiple cleft conditions)

Note: The Alaska Birth Defects Registry (ABDR) was established and operates under Alaska statute 7 AAC 27.012. Statue allows reports to by age three years of a child. This report includes defects reported before the third birthday.

Column descriptions:
Defect = The Nationally reportable birth defect grouping name.
Reports = Unless otherwise noted, the number of unique reports of defect received by ABDR during the specified birth year(s). Each report represents a unique child with specified defect.
Report Prevalence (95% CI) = The number of reported defects divided by the number of Alaska resident in-state births (Children can be reported multiple times. they are counted only once for each condition).
PPV = The probability of being defect positive given being reported for the defect.
NPV = The probability of being defect negative given not being reported for the defect.
Estimated Defects = The estimated number of defects based on the report prevalence, PPV, and 1-NPV.
Defect Prevalence (95% CI) = The estimated defect prevalence calculated using a Bayesian approach based on the reported prevalence, PPV and 1-NPV (see formula below).

*Through medical records review and case confirmation of a random sample of reported cases, the defect prevalence is calculated as:

\[PPV (Positive Predictive Value) = p(defect)|report)\] \[NPV (Negative Predictive Value) = p(\overline{defect}|\overline{report})]\]

\[p(defect) \approx [p(report)\cdot PPV]+[p(\overline{report})\cdot 1-NPV)]\]

Defect prevalence estimates are a more accurate estimation of the actual diagnosed prevelance of birth defects compared to the reported prevelance estimates in Alaska. ABDR obtains reports from medical providers using International Classification of Disease (ICD) codes that are extracted from individual systems which when aggregated may not reflect true diagnostics. Caution should be used when interpreting and comparing the reported prevalence estimates with national estimates.

Condition Notes:

Hypospadias is restricted to male births (N = 29187).
Turner Syndrome is restricted to female births (N = 27708).

Resources:
National Birth Defects Prevention Network
Centers for Diesase Control and Prevention