A pilot study for long-term outcome assessment after aortic aneurysm repair using Vascular Quality Initiative data matched to Medicare claims

Abstract

Objective: Accurate and complete long-term postoperative outcome data are critical to improving value in health care delivery. The Society for Vascular Surgery Vascular Quality Initiative (VQI) is an important tool to achieve this goal in vascular surgery. To improve on the capture of long-term outcomes after vascular surgery procedures for patients in the VQI, we sought to match VQI data to Medicare claims for comprehensive capture of major clinical outcomes in the first several years after vascular procedures.

Methods: Patient and procedure characteristics for abdominal aortic aneurysm procedures captured in the Society for Vascular Surgery VQI between January 1, 2002, and December 31, 2013, were matched to Medicare claims data using an indirect identifier methodology. Late outcomes captured in the VQI and in Medicare claims were compared.

Results: Matching procedures yielded 9895 endovascular aneurysm repair (EVAR) patients (82.4% of eligible VQI patients) and 3405 open aneurysm repair (OAR) patients (74.4% of eligible). Comparison of patients who did and did not match to a Medicare claim demonstrated similar patient and procedure characteristics. Evaluation of late outcomes revealed good patient-level agreement on mortality for both EVAR (κ, 0.64) and OAR (κ, 0.82). Postoperative reintervention rates demonstrated lower agreement for both EVAR (κ, 0.26) and OAR (κ, 0.16).

Conclusions: This work demonstrates the feasibility of an algorithm using indirect identifiers to match VQI patients and procedures to Medicare claims data. The refinement of this strategy will focus on establishing and improving algorithms related to identifying and categorizing late events after EVAR and may serve as a mechanism to ensure that the best quality follow-up information is achieved within the VQI.

Figure 1

Graphical representation of data security and matching process. All patient and physician identifiers are securely maintained within the VQI and TDI (Group C and Group D). Only de-identified matched (Group A) and unmatched (Group B) data leave the secure environment for review including quality improvement and research work.

Figure 2

Flow diagram for matching procedures for patients that have undergone EVAR (A) and OAR (B).

Figure 3

Kaplan-Meier estimate for survival after EVAR (A) and OAR (B) as collected in the VQI (blue) and in Medicare claims data (red).

Figure 4

Kaplan-Meier estimate for freedom from reintervention after EVAR (A) and OAR (B) as collected in the VQI (blue) and in Medicare claims data (red).