Use of structured and unstructured data to identify contraceptive use in women veterans

Contraceptive use among women Veterans may not be adequately captured using administrative and pharmacy codes. Clinical progress notes may provide a useful alternative. The objectives of this study were to validate the use of administrative and pharmacy codes to identify contraceptive use in Veterans Health Administration data, and to determine the feasibility and validity of identifying contraceptive use in clinical progress notes. The study included women Veterans who participated in the Women Veterans Cohort Study, enrolled in the Veterans Affairs Connecticut Health Care System, completed a baseline survey, and had clinical progress notes from one year prior to survey completion. Contraceptive ICD-9-CM codes, V-codes, CPT codes, and pharmacy codes were identified. Progress notes were annotated to identify contraceptive use. Self-reported contraceptive use was identified from a baseline survey of health habits and healthcare practices and utilization. Sensitivity, specificity, and positive predictive value were calculated comparing administrative and pharmacy contraceptive codes and progress note-based contraceptive information to self-report survey data. Results showed that administrative and pharmacy codes were specific but not sensitive for identifying contraceptive use. For example, oral contraceptive pill codes were highly specific (1.00) but not sensitive (0.41). Data from clinical progress notes demonstrated greater sensitivity and comparable specificity. For example, for oral contraceptive pills, progress notes were both specific (0.85) and sensitive (0.73). Results suggest that the best approach for identifying contraceptive use, through either administrative codes or progress notes, depends on the research question.