Clinical practice guidelines in unstable angina improve clinical outcomes by assuring early intensive medical treatment

J Am Coll Cardiol. 1999 Nov 15;34(6):1689-95. doi: 10.1016/s0735-1097(99)00405-2.


Objectives: To determine the influence of clinical practice guidelines on treatment patterns and clinical outcomes in unstable angina and the effectiveness of guideline reminders on implementing practice guidelines, two groups of medium and high risk patients with unstable angina were compared.

Background: New guidelines have been published by the Agency for Health Care Policy and Research (AHCPR) for evaluating and managing patients with unstable angina. The impact of these guidelines to improve the quality of care has never been tested.

Methods: Group 1 included 338 consecutive medium or high risk patients admitted before publication of the AHCPR guidelines, and group 2 consisted of 181 consecutive similar risk patients admitted after institution of the AHCPR guideline reminders at this institution. Dissemination of clinical practice guidelines was ensured by a grand rounds lecture and by posting guideline reminders on all group 2 patients' charts within 24 h of admission.

Results: The two groups were similar in terms of most baseline characteristics, including hypercholesterolemia, diabetes, hypertension, smoking history, baseline ST segment depression and previous coronary artery bypass graft surgery. Group 1 patients were older (68+/-13 vs. 63+/-16 years, p = 0.001) and more frequently had a previous myocardial infarction (39% vs. 22%, p = 0.001). Group 2 patients more frequently required intravenous nitroglycerin to control the index episode of chest pain (43% vs. 34%, p = 0.003). Group 2 patients more frequently received aspirin (96% vs. 88%, p = 0.009) during admission and underwent coronary angiography (71% vs. 58%, p = 0.006). More importantly, group 2 patients received oral beta-blockers (p = 0.008), aspirin and coronary angiography (p = 0.001) earlier than group 1 patients and experienced recurrent angina (29% vs. 54%) and myocardial infarction or death less frequently (3% vs. 9%, p = 0.028).

Conclusions: In unstable angina, clinical practice guidelines were associated with greater use of aspirin and coronary angiography and greater use and earlier administration of beta-blockers. Variation in drug use over time was also reduced. Objective improvement in clinical outcome was also noted. Thus, practice guidelines improve the quality of care of patients with unstable angina.

MeSH terms

  • Adrenergic beta-Antagonists / therapeutic use
  • Aged
  • Angina, Unstable / therapy*
  • Anti-Inflammatory Agents, Non-Steroidal / therapeutic use
  • Aspirin / therapeutic use
  • Guideline Adherence
  • Humans
  • Logistic Models
  • Middle Aged
  • Practice Guidelines as Topic
  • Practice Patterns, Physicians'*
  • Treatment Outcome


  • Adrenergic beta-Antagonists
  • Anti-Inflammatory Agents, Non-Steroidal
  • Aspirin