A comparison of the national registry of myocardial infarction 2 with the cooperative cardiovascular project

Abstract

Objectives: This study was performed to evaluate whether or not the simpler case identification and data abstraction processes used in National Registry of Myocardial Infarction two (NRMI 2) are comparable with the more rigorous processes utilized in the Cooperative Cardiovascular Project (CCP).

Background: The increased demand for quality of care and outcomes data in hospitalized patients has resulted in a proliferation of databases of varying quality. For patients admitted with myocardial infarction, there are two national databases that attempt to capture critical process and outcome data using different case identification and abstraction processes.

Methods: We compared case ascertainment and data elements collected in Medicare-eligible patients included in the industry-sponsored NRMI 2 with Medicare enrollees included in the Health Care Financing Administration-sponsored CCP who were admitted during identical enrollment periods. Internal and external validity of NRMI 2 was defined using the CCP as the "gold standard."

Results: Demographic and procedure use data obtained independently in each database were nearly identical. There was a tendency for NRMI 2 to identify past medical histories such as prior infarct (29% vs. 31%, p < 0.001) or heart failure (21% vs. 25%, p < 0.001) less frequently than the CCP. Hospital mortality was calculated to be higher in NRMI 2 (19.7% vs. 18.1%, p < 0.001) due mostly to the inclusion of noninsured patients 65 years and older in NRMI 2.

Conclusions: We conclude that the simpler case ascertainment and data collection strategies employed by NRMI 2 result in process and outcome measures that are comparable to the more rigorous methods utilized by the CCP. Outcomes that are more difficult to measure from retrospective chart review such as stroke and recurrent myocardial infarction must be interpreted cautiously.