Comparison of information content of structured and narrative text data sources on the example of medication intensification

Abstract

OBJECTIVE To compare information obtained from narrative and structured electronic sources using anti-hypertensive medication intensification as an example clinical issue of interest. DESIGN A retrospective cohort study of 5,634 hypertensive patients with diabetes from 2000 to 2005. MEASUREMENTS The authors determined the fraction of medication intensification events documented in both narrative and structured data in the electronic medical record. The authors analyzed the relationship between provider characteristics and concordance between intensifications in narrative and structured data. As there is no gold standard data source for medication information, the authors clinically validated medication intensification information by assessing the relationship between documented medication intensification and the patients' blood pressure in univariate and multivariate models. RESULTS Overall, 5,627 (30.9%) of 18,185 medication intensification events were documented in both sources. For a medication intensification event documented in narrative notes the probability of a concordant entry in structured records increased by 11% for each study year (p < 0.0001) and decreased by 19% for each decade of provider age (p = 0.035). In a multivariate model that adjusted for patient demographics and intraphysician correlations, an increase of one medication intensification per month documented in either narrative or structured data were associated with a 5-8 mm Hg monthly decrease in systolic and 1.5-4 mm Hg decrease in diastolic blood pressure (p < 0.0001 for all). CONCLUSION Narrative and structured electronic data sources provide complementary information on anti-hypertensive medication intensification. Clinical validity of information in both sources was demonstrated by correlation with changes in blood pressure.

Figure 1

Periods of Continuously Elevated Blood Pressure. Circles represent individual physician–patient encounters.

Figure 2

Distribution of Concordance between Medication Intensification Documentation in Narrative and Structured Data among Providers. For each provider who has had an encounter with at least one study patient, the average concordance of medication intensification was calculated as the fraction of anti-hypertensive medication intensifications documented in the notes that had medication intensifications documented in structured EMR records for the same encounter. Intervals of concordance of medication intensification were plotted against the number of providers whose average concordance fell into these intervals.

Figure 3

A. Average Monthly Change in Systolic Blood Pressure (SBP) by Frequency of Treatment Intensification Documented Both in the Notes and Structured Records.The average number of anti-hypertensive medication intensifications per month of continuously elevated blood pressure was plotted against the average change in blood pressure, mm Hg/mo. B. Average Monthly Change in Diastolic Blood Pressure (DBP) by Frequency of Treatment Intensification Documented Both in the Notes and Structured Records. C. Average Monthly Change in Systolic Blood Pressure by Frequency of Treatment Intensification Documented in the Structured Records but Not in the Notes. D. Average Monthly Change in Diastolic Blood Pressure by Frequency of Treatment Intensification Documented in the Structured Records but Not in the Notes. E. Average Monthly Change in Systolic Blood Pressure by Frequency of Treatment Intensification Documented in the Notes, but Not in the Structured Records. F. Average Monthly Change in Diastolic Blood Pressure by Frequency of Treatment Intensification Documented in the Notes, but Not in the Structured Records.