International Variation in Health Status Benefits in Patients Undergoing Initial Invasive Versus Conservative Management for Chronic Coronary Disease: Insights From the ISCHEMIA Trial.

BACKGROUND

The ISCHEMIA trial (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches) demonstrated greater health status benefits with an initial invasive strategy, as compared with a conservative one, for patients with chronic coronary disease and moderate or severe ischemia. Whether these benefits vary globally is important to understand to support global adoption of the results.

METHODS

We analyzed participants' disease-specific health status using the validated 7-item Seattle Angina Questionnaire (SAQ: >5-point differences are clinically important) at baseline and over 1-year follow-up across 37 countries in 6 international regions. The average effect of initial invasive versus conservative strategies on 1-year SAQ scores was estimated using Bayesian proportional odds regression and compared across regions.

RESULTS

Considerable regional variation in baseline health status was observed among 4617 participants (mean age=64.4±9.5 years, 24% women), with the mean SAQ summary scores of 67.4±19.5 in Eastern Europe participants (17% of the total), 71.4±15.4 in Asia-Pacific (18%), 74.9±16.7 in Central and South America (10%), 75.5±19.5 in Western Europe (26%), and 78.6±19.2 in North America (28%). One-year improvements in SAQ scores were greater in regions with lower baseline scores with initial invasive management (17.7±20.9 in Eastern Europe and 11.4±19.3 in North America), but similar in the conservative arm. Adjusting for baseline SAQ scores, similar health status benefits of an initial invasive strategy on 1-year SAQ scores were observed (ranging from 2.38 points [95% CI, 0.04-4.50] in North America to 4.66 points [95% CI, 2.46-6.94] in Eastern Europe), with an 88.3% probability that the difference in benefit across regions was <5 points.

CONCLUSIONS

In patients with chronic coronary disease and moderate or severe ischemia, initial invasive management was associated with a consistent health status benefit across regions, with modest regional variability, supporting the international generalizability of health status benefits from invasive management of chronic coronary disease.

REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01471522.