The ankle-brachial index for peripheral artery disease screening and cardiovascular disease prediction among asymptomatic adults: a systematic evidence review for the U.S. Preventive Services Task Force.

BACKGROUND

Screening for peripheral artery disease (PAD) may reduce morbidity and mortality.

PURPOSE

To review the evidence on the ability of the ankle-brachial index (ABI) to predict cardiovascular disease (CVD) morbidity and mortality independent of Framingham Risk Score (FRS) factors in asymptomatic adults and on the benefits and harms of treating screen-detected adults with PAD.

DATA SOURCES

MEDLINE and the Cochrane Central Register of Controlled Trials (1996 to September 2012), clinical trial registries, reference lists, and experts.

STUDY SELECTION

English-language, population-based prognostic studies evaluating the ABI in addition to the FRS and treatment trials or studies of treatment harms in screen-detected adults with PAD.

DATA EXTRACTION

Dual quality assessment and abstraction of relevant study details.

DATA SYNTHESIS

One large meta-analysis (n = 43 919) showed that the ABI could reclassify 10-year risk for coronary artery disease (CAD), but it did not report measures of appropriate reclassification (the net reclassification improvement [NRI]). Four heterogeneous risk prediction studies showed that the magnitude of the NRI was probably small when the ABI was added to the FRS to predict CAD or CVD events. Of 2 treatment trials meeting inclusion criteria, 1 large trial (n = 3350) showed that low-dose aspirin did not prevent CVD events in persons with a screen-detected low ABI but may have increased the risk for major bleeding events.

LIMITATIONS

Most prognostic studies did not allow for calculation of a bias-corrected NRI. Evidence on treatment benefits and harms was limited to aspirin and was scant.

CONCLUSION

Adding the ABI to the FRS probably has limited value for predicting CAD or CVD. Treatment benefits for asymptomatic individuals with screen-detected PAD are not established.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.