Predictive Value of the International Classification of Diseases, 9th Revision Codes for Identifying Ocular Oncology Diagnoses.

The aim of this study was to determine the predictive value of International Classification of Diseases, 9th Revision (ICD-9) billing codes for identifying ocular oncology diagnoses. Population-based retrospective cohort study of all Olmsted County, Minnesota residents with any ocular neoplasm-related ICD-9 code from January 1, 2006 to October 1, 2015. All medical records were reviewed for confirmation of ocular neoplasm. Diagnoses with ≥5 cases confirmed via a medical record review were compared to corresponding ICD-9 codes. Main outcome measures included positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity of ICD-9 codes. Among 3,932 subjects with ≥1 ocular neoplasm-related ICD-9 code, 21 diagnoses met study criteria. The most frequent intraocular, extraocular/orbital, and ocular surface diagnoses were choroidal nevus (n = 824), epidermal inclusion cyst (n = 263), and conjunctival nevus (n = 74), respectively. PPVs ranged from 1.2% to 73.8%, NPVs from 96.9% to 100%, sensitivity from 0% to 100%, and specificity from 85.7% to 100%. Among malignant neoplasms, PPV ranged from 0% to 73.8%: ocular surface squamous neoplasia (PPV: 0%), choroidal melanoma (PPV: 25.0%), eyelid squamous cell carcinoma (PPV: 46.7%), and eyelid basal cell carcinoma (PPV: 73.8%). Among benign neoplasms, PPV ranged from 1.2% (dermoid cyst) to 61.6% (choroidal nevus). There was a wide variation in a predictive value of ocular neoplasm-related ICD-9 billing codes, which suggests that ocular oncology-related claims data alone may overestimate the true number of ocular oncology diagnoses.