Accuracy of International Classification of Diseases, Ninth Revision, Clinical Modification Billing Codes for Common Ophthalmic Conditions

Abstract

To the EditorAn increasing number of analyses use administrative claims data to study the epidemiology, risk factors, and resource consumption associated with patients with ocular diseases. These sources of voluminous data allow researchers to study common and uncommon conditions and assess care delivered by different providers in various communities. Since claims data are collected primarily for billing, not research purposes, a concern is whether the diagnoses listed in the billing records reflect the actual conditions described in the medical record. 1 If claims data were found to inaccurately reflect patients' conditions, the usefulness of these data for research would be limited. The accuracy of claims data has been examined for selected eye diseases but not for many common ophthalmic conditions. [2][3][4] We examine the accuracy of claims data for five such conditions. MethodsWith Institutional Review Board approval, 982 consecutive billing records of patients coded with the following ocular conditions were identified from two academic medical centers: cataract (International Classification of Disease-9 [ICD-9-CM] codes 366-366.4), glaucoma suspect (365.0), primary open angle glaucoma (OAG) (365.11), proliferative diabetic retinopathy (PDR) (362.02), and nonexudative macular degeneration (NEAMD) (362.51). One abstractor (KWM) reviewed the documentation in the medical record for each billed encounter and scored the billing code as correct or incorrect. An encounter was classified as billed correctly if evidence in the medical record substantiated that the patient had the condition indicated on the billing form. If no such confirmatory evidence was found, the encounter was classified as billed incorrectly. ResultsOf the 982 encounters reviewed, 949 (97%) were coded correctly. The proportion of encounters with correct codes ranged from 92% (NEAMD) to 100% (cataract) (Table 1).

Impact of diagnosing diabetic complications on future hemoglobin A1c levels

“…First, as with all claims data analyses, there is the potential that persons were miscoded or misdiagnosed with the conditions of interest. However, a recent study comparing the accuracy of billing codes to those obtained from actual medical records showed that billing records accurately reflected selected ocular conditions listed in the medical charts approximately 97% of the time (Muir, Gupta, Gill, & Stein, 2013). Second, as our population consisted of individuals with health insurance who had received some form of eye care, the results may not be generalizable to other populations who lack health insurance or those who have never received eye care.…”

Incidence and Risk Factors for Developing Diabetic Retinopathy among Youths with Type 1 or Type 2 Diabetes throughout the United States

“…In addition, billing code errors may also contribute to misclassification errors in determining presence and type of DR, though a recent study validating billing codes in common ophthalmic disorders (including proliferative DR) found a 97% accuracy rate compared to medical record documentation. 43 Clinical data such as visual acuity, retinal examination findings, or ophthalmologic imaging and testing were unavailable, and verification of DR presence or severity was infeasible. Youth were likely seen by eye care providers who had varying levels of experience and expertise in diagnosing DR and some may have had access to diagnostic equipment to facilitate diagnosis of DR while others may not have had access to such equipment.…”

Geographic Variation in the Rate and Timing of Cataract Surgery Among US Communities

“…Prior work comparing billing records with medical records found that billing records accurately capture persons with cataracts. 8 …”