Factors influencing efficacy of nitrate therapy for stable angina pectoris: a multiple linear regression analysis

In an open-label self-controlled study of 1,350 patients with stable angina pectoris (SAP), we previously demonstrated that 50 mg of isosorbide mononitrate (ISMN) slow release formulation once daily not only provided a better antianginal effect but also a better quality of life (QOL) than did the daily administration of multiple small doses of the compound. It is unknown whether certain patient characteristics contribute to this benefit. The objective of this article was to determine what independent factors contribute to this benefit. Multiple linear regression analysis was performed on the data from these 1,350 patients. Quality of life was assessed by the Marquis QOL-questionnaire for patients with angina and included the domains of immobility, pain, and psychological distress. For the purpose of this study, overall QOL was calculated as the pooled sums of the domain scores and expressed as mean scores on an ordinal scale of 10. Age did not influence the beneficial effect of nitrate therapy on QOL. Neither did gender, rhythmic disturbances, peripheral artery disease, or the concomitant use of calcium channel blockers or beta blockers. New York Heart Association (NYHA) angina classification was an independent variable: patients with a NYHA class I or II benefited less than did patients with NYHA III or IV (p = 0.02). Obese patients as well as hypertensive patients benefited less (p = 0.04 and 0.02), and smokers tended to benefit less also (p = 0.08). In contrast, hypercholesterolemia and diabetes mellitus improved the beneficial effect of nitrates on QOL (p = 0.03 and 0.05). The authors conclude that patients with coronary artery disease (CAD) and concomitant diabetes mellitus or hypercholesterolemia, a category particularly prone to early endothelial dysfunction and thus dysfunctional endogenous nitric oxide (NO) production, may benefit more from NO-donor therapy than patients without such concomitant conditions.