Comparison of multiple-dose and once-daily nitrate therapy in 1212 patients with stable angina pectoris: effects on quality of life indices. Dutch Mononitrate Quality of Life (DUMQOL) Study Group.

BACKGROUND: Nitrates, although important for the management of anginal symptoms, produce significant side effects. Little is known about their net effects on health-related, quality-of-life indices.
METHODS: In a self-controlled, 6-month study, the effects on symptoms and quality of life of multiple-dose and once-daily nitrate therapy 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.
RESULTS: The effects of the two treatment regimens on pain index and number of additional sublingual nitrate tablets required were not different. However, based on the New York Heart Association (NYHA) angina classification, patients improved better on the once-daily than on the multiple-dose regimen: by > 1 category in 281 vs 62 of the patients (P < 0.0001); mobility and psychological distress indices also improved (P = 0.006, and P = 0.007).
CONCLUSIONS: Once-daily nitrate therapy not only provides a better NYHA angina classification than multiple-dose therapy does, but also provides a better quality of life as estimated by improvement of mobility and distress indices, the most important indicators of quality of life in this category of patients.