Background: An unstable angina guideline was published in 1994 by the Agenc
y for Health Care Policy and Research, Bethesda, Md. However, the relations
hip between guideline-concordant care and patient outcomes is unknown.
Objective: To determine whether guideline-concordant care is associated wit
h improved outcomes.
Methods: The study sample consisted of 275 consecutive nonreferral patients
hospitalized with primary unstable angina. One-year survival and survival
free of myocardial infarction were compared between patients who received c
are concordant with 8 selected guideline recommendations and patients who r
eceived discordant care.
Results: Care concordant with the 8 key guideline recommendations was assoc
iated with improved 1-year survival (95% vs 81%; log-rank P<.001) and survi
val free of myocardial infarction (91% vs 74%; P<.001), compared with guide
line-discordant care. Patients in high risk subgroups had the largest survi
val benefit associated with guideline-concordant care (aged greater than or
equal to 65 years, 91% vs 74% [P=.005]; heart failure at presentation, 91%
vs 68% [P=.10]). Aspirin therapy was the single recommendation most strong
ly associated with improved 1-year survival (94% vs 78%; P=.002).
Conclusions: Care as outlined in the unstable angina clinical practice guid
eline is associated with improved 1-year outcomes. Subgroups of patients at
highest risk and recommendations firmly based on randomized clinical trial
data were mast strongly associated with better outcomes. These findings su
pport the use of an evidence-based approach to guideline development and as
sessment of quality of care in patients with primary unstable angina.