Comparison of the Seattle Angina Questionnaire With Daily Angina Diary in the TERISA Clinical Trial
In patients in the TERISA (Type 2 Diabetes Evaluation of Ranolazine in Subjects With Chronic Stable Angina) clinical trial, what was the correlation between responses on the Seattle Angina Questionnaire (SAQ) angina frequency (AF) scale and daily diary entries of angina and use of sublingual nitroglycerin?
TERISA was an international, multicenter, double-blind, placebo-controlled trial in which subjects with stable angina and type 2 diabetes mellitus were randomized to 1000 mg twice daily dose of ranolazine or matched placebo for 8 weeks. Through input into an electronic diary, patients were instructed to record the number of angina episodes and number of sublingual nitroglycerin taken in the preceding 24 hours. Disease-specific health status was assessed with the SAQ at randomization and at 8 weeks after study initiation; the SAQ AF scale is comprised of the following two questions: 1) “Over the past 4 weeks, on average, how many times have you had chest pain, chest tightness, or angina?” and 2) “Over the past 4 weeks, on average, how many times have you had to take nitros for your chest pain, chest tightness, or angina?” The authors performed cross-sectional and longitudinal analyses to validate the SAQ AF scale against daily records of angina frequency and sublingual nitroglycerin use.
The analytic sample had 917 patients. There was a correlation between the two SAQ angina frequency questions and the corresponding diary responses in both longitudinal and cross-sectional analyses. In cross-sectional analysis, the correlation coefficients of the SAQ AF scale and angina frequency and sublingual nitroglycerin use were -0.64 (95% confidence interval [CI], -0.68 to -0.60) and -0.69 (95% CI, -0.73 to -0.66), respectively. In longitudinal analyses, the correlation coefficients of the SAQ AF scale and angina frequency and sublingual nitroglycerin use were -0.42 (95% CI, -0.48 to -0.30) and -0.38 (95% CI, -0.43 to -0.32), respectively.
In the multicenter TERISA trial, participant responses on the two-item SAQ AF scale correlated, both cross-sectionally and longitudinally, with daily diary entries of angina frequency and sublingual nitroglycerin usage.
The gold standard for the measurement of angina frequency in clinical trials has been patient-reported daily angina diaries or time to ischemic electrocardiogram changes or symptoms. This is an important study that suggests the value of the self-administered SAQ AF scale. By establishing the validity of the angina frequency domain of the SAQ, the authors have added support to its continued use in clinical trials. Practically, a two-item questionnaire may help relieve the limitations of paper or electronic diaries that capture angina frequency.
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