Research Clinical Data Warehouse

Research IT manages a data commons of all research related data sets at Stanford Medicine. At the core of this data commons is the Stanford Translational Research Integrated Database Environment (STRIDE) clinical data warehouse consisting of Electronic Medical Record (EMR) data going back to 1998. This clinical data warehouse contains data from both hospitals and spans multiple EMR implementations.

Reimbursement codes, also known as billing codes, are one of the more commonly utilized sources of structured data in EMRs. The STRIDE record of diagnosis and procedure codes over time shown in Figure 1 reflects the conversion from paper to electronic records in the 1990s through early 2000s, followed by a steady rate of growth in patients served by the system, starting around 2010.


Billing Code Types in 2016

The above graph shows the number of distinct patients each year with diagnosis or procedure codes since 1998.

The pie chart on the right shows the breakdown of procedure codes for the year 2016.  Roughly half the procedures coded in 2016 pertained to diagnostics such as radiology, pathology and labs. Slightly less than 10% of all procedures coded were classified as surgical, the remaining 40% split roughly evenly between non-surgical intervention and disease management.

Diagnoses coded in 2016 are shown in the pie chart below. These are fairly evenly distributed across the high level clinical categories, indicative of the broad spectrum of health care specialty services offered at Stanford.

Billing Code Types in 2016

The graph below depicts the number of distinct patients each year since 1998 by encounter type - Inpatient, Outpatient, Emergency, and Surgery. 

The steady outpacing of hospital related encounters by outpatient visits reflects the recent transition at Stanford from a focus on tertiary and emergency care services through 2010, to the shift in recent years toward outpatient care. This trend will only accelerate as Stanford continues extends its reach into the community care setting through the University Healthcare Alliance and Packard Childrens’ Healthcare Alliance.

The graph below depicts the number of distinct patients with at least one pharmacy order / lab result in the given year.

As you can see, in 2008 there was a distinct shift from paper prescriptions to electronic medication orders that coincided with the migration from CareCast/LastWord to Epic at SHC. By contrast the transition from paper to electronic records for lab results took place at Stanford in the late 1990s and was complete by the turn of the millenium. It is also interesting that in 2014 the rate of medication ordering started to outpace the record of lab results, indicative of a steadily increasing population of patients receiving their primary care in an outpatient setting. 

Finally, the graph below shows the number of distinct patients each year since 1998 for which the data warehouse has associated narrative documentation: clinical notes, and radiology and pathology reports.

Again here we clearly see evidence of the growth into outpatient services in recent years, reflected by the growth in number of patients with clinic visit notes as compared to the more measured growth rate for diagnostic (radiology and pathology) reports.