Background: Direct feedback on quality of care is one of the key features of the Learning Healthcare System (LHS). This enables health care professionals to improve routine clinical care of their patient’s during practice. In this study, we evaluated the potential of routine clinical care data extracted from the electronic health records in order to obtain reliable information on LDL-c management in cardiovascular patients referred to a tertiary center.
Methods and Findings: We extracted all LDL-c measurements from the electronic health records from patients with a history of cardiovascular disease (CVD) referred to the University Medical Center Utrecht.  We assessed LDL-c target attainment at the time of referral and per year. In patients with multiple measurements we analyzed LDL-c trajectories, truncated at 6 follow-up measurements. Lastly we performed a logistic regression analysis to investigate factors associated with improvement of LDL-c at the next measurement.
Between February 2003 and December 2017 250,749 LDL-c measurements were taken from 95,795 patients, 23,932 of whom had a CVD event. At the time of referral 51% of patients were not on their LDL-c target. A large proportion of patients (55%) had no follow-up LDL-c measurements taken in our center. Most of the patients with repeated measurements showed no change in LDL-c level over time (lower or higher). The timing of drug prescription was difficult to determine from our data, limiting the interpretation of results regarding medication management.
Conclusions: Routine clinical care data can be used to provide feedback on quality of care, such as  LDL-c target attainment. These routine clinical care data show high-off target prevalence and little change in LDL-c over time. Registration of diagnosis, follow-up trajectory including primary and secondary care, and medication use need to be improved to enhance usability of the EHR for adequate feedback of this type of questions.

05 - LEARNING FROM OUR HEALTHCARE SYSTEM: THE ANALYSIS OF LDL-CHOLESTEROL TARGET ATTAINMENT IN PATIENTS WITH ESTABLISHED CARDIOVASCULAR DISEASE IN ROUTINE CARE DATA