Endocrine and renal effects of nifedipine gastrointestinal therapeutic system in patients with essential hypertension. Results of a multicenter trial. The Modern Approach to the Treatment of Hypertension Study Group. Use of thiazide diuretics and beta-blockers in the treatment of hypertension may result in metabolic derangements and/or disturbances in the parameters of renal function, which offset the benefits of blood pressure reduction by adversely affecting other cardiovascular risk factors, particularly in special patient groups such as the elderly or those with concomitant diseases. Newer agents including calcium channel blockers, which exert potent antihypertensive effects without adversely affecting metabolic parameters unfavorably, are used with increasing frequency in hypertensive patients, but their clinical utility has been limited by the need for multiple daily dosing with attendant fluctuations in plasma levels thought to be associated with nuisance side effects and possible gaps in therapeutic protection. The Modern Approach to the Treatment of Hypertension (MATH) trial was conducted to determine the efficacy and safety of the new once-daily nifedipine gastrointestinal therapeutic system (GITS) formulation in a large cohort of mild-to-moderate hypertensive patients overall, and to identify specific effects of therapy in the presence of complicating factors such as diabetes and obesity. A total of 1155 patients from 127 centers were treated with nifedipine GITS in the MATH trial, including 157 diabetic (fasting plasma glucose greater than 120 mg/dL or on hypoglycemic therapy) and 747 nondiabetic patients. There were 458 obese patients (body mass index [BMI] greater than 30), 489 overweight patients (BMI greater than or equal to 25 less than or equal to 30), and 206 patients of normal weight (BMI less than 25). 