Assessing the clinical and economic burden of coronary artery disease: 1986-1998

BACKGROUND. The acute phase of coronary artery disease (CAD) is dramatic an d receives much attention because of its high mortality and associated trea tment cost. However, the acute phase Typically resolves within 30 days wher eas CAD is a chronic disease, which most patients will Live with for mare t han a decade. We compared the clinical and economic burden of CAD during th e acute phase (first 30 days) with that in The postacute phase (31st day th rough 10 years). METHODS. We included acute coronary syndrome (ACS) patients with significan t CAD receiving an initial cardiac catheterization at Duke University Medic al Center between 1986 and 1997 with follow-up continuing through 1998. Inp atient medical costs were estimated from ACS clinical trial and economic st udy data. Costs were adjusted to 1997 values and discounted at 3% per annum . RESULTS. Our study included 9,876 ACS patients (5,557 with an acute myocard ial infarction [MI] anal 4,319 with unstable angina [UA]). Acute MI patient s had higher 30-day mortality than UA patients (5.6% vs. 2.3%, P <0.001). I n addition, acute MI and UA patients had significant 10-year unadjusted and adjusted survival differences (both P <0.001). For patients who survived t o 30 days, there was no difference in 10-year survival between acute MI and UA patients before adjustment (P = 0.472). After adjustment, however, unst able angina patients who survived to 30 days had greater survival than myoc ardial infarction patients (P = 0.011). Mean 10-year discounted ACS inpatie nt medical costs were $45,253 ($23,510 acute phase and $21,819 postacute ph ase, P = 0.002). Ten year costs for unstable angina patients were $46,423 ( $21,824 acute phase and $24,599 postacute phase, P = 0.003); ten year costs for myocardial infarction patients were $44,663 ($24,823 acute phase and $ 19,840 postacute phase, P <0.001). CONCLUSIONS. We found that the clinical and economic burden of CAD continue s long after a patient's acute event has resolved and that postacute CAD ca rdiac event rates and inpatient medical costs may be higher than previously estimated. With much of all medical costs occurring in the postacute phase , the potential for effective secondary prevention therapies is substantial .