The effect of adjusting for baseline risk factors and post revascularisation coronary disease on comparisons between coronary angioplasty and bypass surgery

Background: In CABRI at 1 year PTCA was associated with greater repeat reva scularisation and angina (but not myocardial infarction or death). We deter mined whether adjusting for baseline risk factors and post revascularisatio n coronary disease offsets this disadvantage of PTCA. Methods: In the CABRI population the crude association of revascularisation mode (i.e. PTCA or C ABG) with four clinical outcome (i.e. mortality, myocardial infarction, rep eat revascularisation and angina) was adjusted for the baseline risk factor s using a logistic regression model for each clinical outcome. A number of measures of angiographic coronary disease were used to assess post revascul arisation coronary disease. One at a time, each of these measures was added to each of the four outcome models, to adjust for post revascularisation c oronary disease. Results: Comparing adjusted and crude unadjusted associati on of PTCA with repeat revascularisation there was an increase from 12.8 (P < 0.0005) (crude relative ri:jk) to 16.7 (P < 0.0005) (adjusted odds ratio ), with angina, from 1.89 (P = 0.001) to 1.98 (P < 0.0019), and with mortal ity from 1.84 (P = 0.092) to 2.15 (P = 0.060). PTCA was not significantly a ssociated with myocardial infarction, either crudely or after adjustment. C onclusion: Adjusting for baseline risk factors: and post revascularisation coronary disease tended to strengthen rather than weaken associations betwe en PTCA and 1 year mortality, repeat revascularisation and angina at 1 year . (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.