Comparison of multiple-dose and once-daily nitrate therapy in patients with stable angina pectoris: effects on quality-of-life indices

Abstract

In a 6-month self-controlled study, the effects of multiple-dose and once-daily nitrate therapy on anginal symptoms and quality of life were evaluated in 1212 patients with stable angina pectoris. Quality of life was assessed by a test battery based on the exercise tolerance index of Wiklund, the psychological well-being index of Dupuy, and the Short-Form 36 questionnaire of Stewart. The internal consistency and reliability of the multi-item scales were estimated by Cronbach's alpha coefficients. The effects of the two treatment regimens on pain index and number of additional sublingual nitrate tablets required were similar. However, based on New York Heart Association (NYHA) angina classification, patients showed a statistically significant better improvement with the once-daily than with the multiple-dose regimen: between the first and second evaluation 281 patients improved by one category and 62 patients worsened by one category. Mobility and psychological distress indices also indicated statistically significant higher scores for the once-daily treatment regimen. It can be concluded from this study that once-daily nitrate not only provides a better NYHA angina classification than multiple-dose therapy but also provides a better quality of life as estimated by improvement of mobility and distress indices. Patient compliance, estimated by using the number of patients who reported forgetting to take medication, was greatly improved (from 16% to 21% improvement).