Neonatal Abstinence Syndrome by County

[About the dataset]

Data includes NAS cases (numerator), all live births (denominator) and NAS rate (cases per 1,000 live births) by county of residence in Michigan over a 5 year period. 

[About NAS]

NAS is a constellation of signs of withdrawal in neonates less than 28 days following in utero exposure to substances or prescribed medications, most commonly opioids, benzodiazepines, and barbiturates.

NAS may be underreported, given increased use of non-pharmacological interventions. NAS surveillance does not distinguish between exposure due to an untreated substance use disorder, medication assisted therapy, or long-term treatment for a chronic disease.

[Methods]

Case Definition. Unique NAS cases are currently identified based on the International Classification of Disease (ICD), 10th Revision, Clinical Modification (ICD-10-CM diagnosis code (P96.1), limited to Michigan residents. This inpatient/outpatient diagnosis code is for 'neonatal withdrawal symptoms from maternal use of drugs of addiction'. 

During 2010-2015, NAS cases were identified based on ICD-9-CM diagnosis code 779.5 (drug withdrawal syndrome in newborn). 

Rate calculation. All rates presented are crude rates. Counts and rates are suppressed when the numerator is between 1-5 for privacy and statistical stability purposes. This is indicated by DNS (Data Not Sufficient). The denominator used to calculate rates is the number of live births in the corresponding birth year. 

Rates are calculated per 1,000 live births to be consistent with the CSTE case definition. 

[Limitations]

Cases of neonatal abstinence syndrome are solely identified from inpatient and/or outpatient hospitalization records (inpatient only: 2010-2019, inpatient and outpatient: 2020-2023). 

NAS surveillance does not distinguish between exposure due to untreated substance use disorder (i.e., opioid use disorder or other), medication assisted treatment (i.e., pregnant people receiving treatment for an opioid use disorder), or long-term treatment for a chronic disease  or condition (e.g., pregnant people receiving treatment for chronic pain, anxiety disorders). 

If treatment for NAS is not, or cannot, be billed, the diagnosis code may not be documented in the medical record. In these instances, cases of NAS will not be captured in the data. This is more likely to happen when infants receive non-pharmacological treatments (i.e., decreased stimulation and increased calming techniques/Eat Sleep Console), which have become increasingly common in the state. 

Pregnant patients may not be screened universally and/or tested due provider biases or costs associated with testing.

NAS symptoms may not occur until 5-7 days after birth. Unless re-admitted, infants discharged prior to the presentation of symptoms would not be captured in the data.

[Data Source]

Michigan resident inpatient files (2010-2023) created by the Division for Vital Records and Health Statistics, Michigan Department of Health and Human Services. 

Michigan resident outpatient files (2020-2023) created by the Division for Vital Records and Health Statistics, Michigan Department of Health and Human Services. 

Data is used with permission from the Michigan Health and Hospital Association Service Corporation (MHASC). 

Data linkage to vital records is conducted by the Division of Vital Records and Health Statistics, MDHHS. Analysis completed by the Maternal and Child Health Epidemiology Section, MDHHS.


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For more NAS data:
https://www.michigan.gov/mdhhs/adult-child-serv/childrenfamilies/mchepi/infant-health-epidemiology

NAS Case Definition: https://cdn.ymaws.com/www.cste.org/resource/resmgr/ps/ps_2023/23-MCH-01_NAS.pdf