Table 1. ICD-9-CM Codes Used to Define Exposure and Outcomes of Interest.
| Variable | Data sources | Diagnosis codes |
|---|---|---|
| Parental serious mental illness | Inpatient and outpatient records | Serious mental illness includes schizophrenia, bipolar disorder, and major depressive disorder. ICD-9-CM codes: schizophrenia: 295, 297, 298.3, 298.4, 298.9; bipolar disorder: 296.00-296.16, 296.40-296.81, 296.89-296.99, 298.1, 648.4; MDD: 296.20-296.36, 296.82, 298.0a |
| Child injury events | Inpatient and outpatient recordsb | ICD-9-CM codes: injury: 800-999, excluding 905–909.9 (late effects), 958–958.8 (traumatic complications), and 995–999.9 (complications of medical care); injury types14: fracture skull vault/base: 800-801.9; fracture skull (apart from vault/base): 802-804.9; intracranial injury: 850-854.1; nerve and spinal cord: 950-957.9; burns: 940-949.9; fracture neck and trunk: 805-809.9; fracture upper limb: 810-818.9; fracture lower limb: 820-827.9, 829-829.9; multiple fractures of limbs: 819-819.1, 828-828.1; internal trauma: 860-869.1; vascular injury: 900-904.9; crush injury: 925-929.9; open wounds: 870-897.9; superficial injuries and contusion: 910-924.9; dislocations, strains, and sprains: 830-848.9; foreign body: 930-939.9; poisoning: 960-989.9 |
| Child injury hospitalization | Inpatient and outpatient recordsb | Injury events resulting in hospitalization |
| Child injury death | Inpatient records and death certificatesb | Inpatient records: injury-related ICD-9 codes and an expired discharge status; death certificates: D_CODE (ICD-9 E codes) from 2004 to 2007: accident: 800-949, homicide: 960-969, trauma (ICD-9 codes) from 2004 to 2007: 800-994; ICD-10 (ICD-10 codes) after 2008: accident: V01-X59, Y85-Y86; homicide: X85-Y09 |
| Child appendicitis (negative control) | Inpatient and outpatient recordsb | ICD-9-CM codes: 540-542 |
Abbreviations: ICD-9, International Classification of Diseases, Ninth Revision; ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification; ICD-10, International Statistical Classification of Diseases and Related Health Problems, Tenth Revision; MDD, major depressive disorder; SMI, serious mental illness.
a
The SMI value was positive after the date of onset for maternal or paternal SMI, whichever came first.
b
Because infants are typically covered by their parents’ insurance for 60 days, we first retrieved parents’ health claims that belonged to infants (eMethods 4 in the Supplement) as well as all child health claims.