Table 1.
Categories of Co-Occurring Conditions Used in This Study, Specific Conditions Comprising These Categories, and Their International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) Codes
| Category of condition | Specific condition | ICD-9-CM codes |
|---|---|---|
| Auditory disorders | Disorders of external ear | 380.xx |
| Otitis media | 381.xx, 382.xx | |
| Hearing loss | 389.xx | |
| Developmental delays | Speech/language disorder | 315.3x |
| Coordination disorder | 315.4 | |
| Mixed development disorder | 315.5 | |
| Other or unspecified delays | 315.8,315.9 | |
| Gastrointestinal disorders/symptoms | Noninfective enteritis and colitis | 555.xx, 556.xx, 558.xx |
| Constipation | 564.0x | |
| Irritable bowel syndrome | 564.1x | |
| Diarrhea | 787.91 | |
| Abdominal pain | 789.0x | |
| Immune disorders | Food allergy | V15.01–V15.05,692.5,693.1,995.6x, 995.7 |
| Rhinitis | 477.xx | |
| Asthma | 493.xx | |
| Dermatitis | 691.8x, 692.xx | |
| Other allergies | V14.xx,V15.06-V15.09,287.0, 372.05,372.14, 708.0,995.2, 995.20,995.29,995.3 | |
| Psychiatric disorders | Episodic mood disorders | 296.xx, 311.xx |
| Anxiety (and related) | 300.xx | |
| Oppositional defiant disorder | 313.81 | |
| Hyperkinetic syndrome (incl. attention deficit disorders) | 314.xx | |
| Seizure disorders | Epilepsy | 345.xx |
| Other convulsions | 780.39 | |
| Sleep disorders | Insomnia | 307.41, 307.42,327.0x, 780.52 |
| Hypersomnia | 307.43, 307.44,327.1x, 780.54 | |
| Parasomnia | 307.46, 307.48,327.4x, 780.56 | |
| Sleep-disordered breathing |
327.2x, 780.51,780.53,780.57, 786.03 | |
| Infant apnea | 770.81, 770.82 | |
| Orcadian rhythm disorder | 780.55, 307.45,327.3x | |
| Sleep-related movement disorder |
327.5x, 333.94,780.58 | |
| Not otherwise specified |
307.40, 307.47,307.49, 327.8x, 780.50, 780.59 |