Validity of Administrative Coding for Nonarteritic Ischemic Optic Neuropathy

Area of Science:

• Ophthalmology
• Health Informatics
• Medical Coding

Background:

• Administrative claims data are frequently used to study nonarteritic ischemic optic neuropathy (NAION).
• The accuracy of International Classification of Diseases (ICD)-10 codes for identifying NAION in these datasets has not been previously validated.
• Validating ICD-10 codes is crucial for reliable epidemiological research on NAION.

Purpose of the Study:

• To assess the validity of ICD-10 codes for identifying nonarteritic ischemic optic neuropathy (NAION) in administrative claims data.
• To determine the positive predictive value (PPV) of ICD-10 codes for NAION.
• To evaluate how provider specialty influences the PPV of NAION diagnosis codes.

Main Methods:

• Retrospective chart review of 161 patients with at least one ICD-10 code for NAION from three academic centers in 2018.
• Calculation of positive predictive value (PPV) for ICD-10 NAION codes overall and stratified by subspecialty and number of codes.
• Comparison of coded diagnoses against final clinical diagnoses, incorporating presenting symptoms, examination findings, and specific NAION case definitions.

Main Results:

• The overall PPV for ICD-10 NAION codes was 74.5%.
• PPV increased to 86.8% when restricted to neuro-ophthalmology encounters.
• Discrepancies in coding were often due to a lack of documented optic disc edema, even when a final clinical diagnosis of NAION was made.

Conclusions:

• ICD-10 codes demonstrate high validity for identifying nonarteritic ischemic optic neuropathy (NAION) in administrative claims data.
• The accuracy of NAION coding is significantly enhanced when linked to neuro-ophthalmology specialists.
• These findings support the use of ICD-10 codes for NAION research, with consideration for provider specialty.