Key Metric # 2

Performance Tracking (selecting and reporting metrics)

Key metric # 2: incidence of hospital-acquired VTE

Ultimately what your team cares most about is how well the steps of care delivery come together to prevent hospital-acquired VTE, the main clinical endpoint/outcome. Clearly, the incidence of hospital-acquired VTE must be one of your team’s key metrics.

A common definition for “hospital-acquired DVT or PE” would be a clot first discovered during the course of hospitalization, or discovered within 30 days of a prior hospitalization.

There are various methods for trying to capture this metric in a useful way, each with its own advantages in terms of accuracy and efficiency.

   Methods for Defining Hospital-Acquired VTE

*Then divide by 2 to estimate the fraction that is hospital-acquired. The literature suggests that approximately half of all cases of DVT and PE diagnosed in the hospital are hospital-acquired. Alternately, use all VTE codes listed as a secondary diagnosis as a surrogate for hospital-acquired VTE.

The first method is very simple and can be done with no effort, but you won’t have confidence that you are reducing hospital-acquired VTE without some form of chart review. The diagnosis codes for DVT and PE appear in Appendix B.

The “Better yet” option introduces the concept that you can actually get more from the chart review than just a classification of “hospital-acquired” versus “community- acquired.” The VTE can now also be classified as “hospital-acquired while on appropriate prophylaxis” versus “hospital-acquired while not on appropriate prophylaxis.” With this method you can plot the incidence of “preventable HA-VTE,” a subset of all HA-VTE events that communicates the most about your entire VTE prevention effort. This option would also allow you to look for other factors that led to the formation of a hospital-acquired clot. For example, was the patient sedated or restrained? Did the patient have a central line associated clot, and if so, was the line really needed at the time the clot formed? Given the time and resources, you could do a mini-root cause analysis to generate other potential strategies to prevent hospital-acquired VTE.

The “Best” option has all of the advantages listed above, but with the additional advantages that chart review is much easier when the patient is still in the hospital. And the chart review can also be more efficient if you have the capability to query your digital imaging system to screen all pertinent imaging studies on a regular basis. In the 350 bed facility at UCSD a nurse or nurse practitioner screens all pertinent studies from the prior day, identifies all new hospital-acquired clots, and completes a thorough chart review on all new hospital-acquired VTE. The whole process takes less than an hour on each weekday. It can be done very efficiently by using automated search criteria if your radiology department uses a digital imaging system – you can create a reporting system that pulls up all pertinent diagnostic studies, complete with their reports, at the click of a button.

You may well come up with another method that is more useful and expedient in your setting.

Once you define “hospital-acquired VTE” and how you will find them, you have another decision. Will you simply track the raw number of hospital-acquired VTE, or do you want to control for the number of patients or patient-days? Controlling for patient days at risk for VTE does add a little more work, but would reduce some of the “noise” in your data by controlling for the probability that more hospital-acquired VTE will occur when you have a full census. At UCSD, for example, each month we calculate the total number of patient days for adult inpatients in the hospital > 48 hours and use that as the denominator. We use the total number of hospital-acquired VTE events is used as the numerator. This helped us generate a specific aim, outlined in the next section. 

Another option to consider if you have the capacity to look at all newly diagnosed events of DVT and PE in your medical center: if you can track the number of days between hospital- acquired VTE events and/or hospital-acquired preventable VTE events, a “days between events” would be a great way to demonstrate progress (each event is a point on the x axis, while the number of days between events appears on the y axis).

OK, enough background and options. Now it’s time for your team to decide, given the resources at your hospital, how you will measure the incidence of hospital-acquired VTE.

Download the VTE Implementation Guide Snapshot