A SINGLE-MASKED STUDY COMPARING DOXAZOSIN AND ENALAPRIL IN PATIENTS WITH NON-INSULIN-DEPENDENT DIABETES-MELLITUS AND HYPERTENSION

Angiotensin-converting enzyme (ACE) inhibitors are recognized as emine ntly suitable drugs for the treatment of hypertensive patients with no n-insulin-dependent diabetes mellitus (NIDDM). They are metabolically neutral, may reduce insulin resistance, and are renoprotective. Long-a cting alpha(1)-blockers such as doxazosin are also metabolically neutr al, effective antihypertensive agents. The objective of this study was to compare the efficacy and acceptability of doxazosin and the ACE in hibitor enalapril. We investigated the effects of these drugs on blood pressure, diabetic control, lipid levels, renal function, and safety in patients with NIDDM (type II diabetes) and mild-to-moderate hyperte nsion. Fifty-two patients with NIDDM and stable essential hypertension were randomized to two parallel groups. The study comprised three pha ses: placebo washout (4 weeks), dose adjustment monotherapy of doxazos in 1 to 4 mg/d or enalapril 5 to 20 mg/d (8 weeks), and maintenance (4 weeks). Patients not controlled on monotherapy entered a 4-week, open -label, dual-therapy phase before maintenance. Black patients were exc luded, as were those with macroalbuminuria (urinary albumin >3.5 g/24 h) and renal failure (serum creatinine greater than or equal to 150 mu mol/L). Variables being compared included critical blood pressure (CB P) tie, the lesser of mean sitting and standing diastolic blood pressu re [DBP]), sitting and standing systolic blood pressure (SEP) and DBP, blood glucose (fasting and postprandial), serum cholesterol levels, s erum triglyceride levels, body mass index (BMI), and electrocardiograp hic (EGG) evidence of left ventricular hypertrophy. Patients in the do xazosin group exhibited a larger decrease in CBP (-11.3 vs -6.2 mm Hg) , sitting (-9.9 vs -1.1) and standing SBP (-10.3 vs 0.0), and sitting (-12.2 vs -8.4) and standing DBP (-7.9 vs -0.8) compared with the enal april group. The difference in the reduction in standing DBP was stati stically significant, whereas the other differences did not reach stat istical significance. No statistically significant differences were fo und between the groups in metabolic variables, BMI, or ECG findings. T he metabolic profiles of enalapril and doxazosin were similar, except for a mild increase in serum triglyceride levels in the doxazosin grou p. However, the confidence index for the doxazosin-enalapril differenc e was wide, meaning that no conclusive statement can be made about the difference. Adverse events were common (26.9% doxazosin vs 42.3% enal april), but none were serious. The doxazosin-treated patients showed a larger decrease in blood pressure on average than patients receiving enalapril; apart from standing DBP, the differences were not statistic ally significant; This study has demonstrated that doxazosin is at lea st as effective as enalapril in decreasing blood pressure in patients with NIDDM and mild-to-moderate hypertension.