Peripheral arterial occlusive disease in general practice: the reproducibility of the ankle-arm systolic pressure ratio.
One of the non-invasive techniques used in the diagnosis of patients with peripheral arterial occlusive disease is the measurement of the Ankle-Arm Systolic Pressure Ratio ("AA-Ratio"). The magnitude of different sources of measurement variation, relevant to clinical practice as well as multi-observer studies, was estimated from a random effects analysis of variance model. Thirty-five GPs and 24 practice assistants performed 503 AA-Ratio measurements on nine patients over a period of nine weeks, using pocket Doppler devices. When the AA-Ratio is used for diagnostic purposes, a 95% prediction interval consisting of the measured value +/- 15-20% AA-Ratio has to be taken into account. Furthermore, when the AA-Ratio is used in the follow-up of a patient with vascular disease, the difference between two subsequent measurements has to be at least 15.6-19.0% AA-Ratio to have an 80% certainty that this difference is not due to (intra-observer) measurement error.
Department of General Practice, University of Limburg, Maastrict, The Netherlands.
J
J
Stoffers
V
V
Kaiser
A
A
Kester
H
H
Schouten
A
A
Knottnerus
D000368:Aged; D000842:Ankle / Q000098:blood supply; D001132:Arm / Q000098:blood supply; D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000379:methods; D005194:Family Practice; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010823:Physician Assistants; D015203:Reproducibility of Results