Variation in patient utilities for outcomes of the management of chronic stable angina. Implications for clinical practice guidelines. Ischemic Heart Disease Patient Outcomes Research Team

Abstract

Objective: Although practice guidelines sometimes make recommendations based on symptom severity, they rarely account for how patients feel about their symptoms. To investigate the possible importance of patient preferences in treatment of ischemic heart disease, we assessed attitudes toward symptoms in patients with angina pectoris.

Design: Case series.

Setting: Ambulatory cardiology clinics at two tertiary care medical centers.

Patients: A total of 220 subjects were selected from 589 patients with chronic stable angina referred from cardiologists to achieve patients samples balanced for sex, race, and angina severity.

Main outcome measures: We measured patients' attitudes toward their angina using the rating scale, time trade-off, and standard gamble utility metrics. Reliability of measurements was evaluated by repeating the assessments 2 weeks later on 50 willing patients.

Results: While the mean responses followed the expected patterns (those with more severe Canadian Cardiovascular Society scores chose lower utilities), attitudes toward symptoms varied substantially among patients with similarly severe angina. For example, there was a 33% chance that a patient with class II angina had a time trade-off utility that was lower (ie, more bothered by symptoms) than a patient with more severe angina (class III/IV). This variation in utilities was not due to random error in the assessments.

Conclusions: Angina patients with similar functional limitation vary considerably in their tolerance for their symptoms, as measured by utilities. Our findings suggest that guidelines for the management of ischemic heart disease should be based on the preferences of the individual patient rather than on symptom severity alone.