Exploring the treatment-risk paradox in coronary disease.

BACKGROUND

The cause of the "treatment-risk paradox" reported for patients with coronary disease is unknown; however, determining the factors that contribute to this paradox is essential to properly design quality improvement interventions.

METHODS

Prospective cohort study enrolling consecutive patients with angiographically proved coronary disease between February 1, 2004, and November 30, 2005, in Alberta.

RESULTS

One month after an angiogram, statins were being taken by 2436 (62.9%) of 3871 patients (mean age, 64 years). High-risk patients were less likely to be taking statins than lower-risk patients (55.8% vs 63.5%; crude odds ratio [OR], 0.72 [95% confidence interval {CI}, 0.57-0.92]; risk ratio [RR], 0.88 [95% CI, 0.79-0.97]), but this treatment-risk paradox was completely attenuated by adjusting for exertional capacity and depressive symptoms (OR, 0.98 [95% CI, 0.75-1.28]; RR, 0.99 [95% CI, 0.89-1.09]). These results were robust across drug classes: while high-risk patients were less likely to be taking angiotensin-converting enzyme inhibitors, aspirin, and statins (25.8% vs 32.3%; crude OR, 0.73 [95% CI, 0.56-0.95]; RR, 0.80 [95% CI, 0.65-0.97]), this association did not persist in the adjusted model (OR, 0.98 [95% CI, 0.72-1.33] [P = .87]; RR, 0.99 [95% CI, 0.79-1.20]).

CONCLUSIONS

The treatment-risk paradox reported in administrative database analyses is attributable to clinical factors not typically captured in these databases (such as functional capacity and depressive symptoms). Interventions to address the treatment-risk paradox should recognize that patients with reduced functional capacity, depression, or both are at higher risk for underuse of these beneficial therapies and should target physicians and patients.