COMPARISON OF EFFECTS OF QUINAPRIL AND METOPROLOL ON GLYCEMIC CONTROL, SERUM-LIPIDS, BLOOD-PRESSURE, ALBUMINURIA AND QUALITY-OF-LIFE IN NON-INSULIN-DEPENDENT DIABETES-MELLITUS PATIENTS WITH HYPERTENSION

Objective. To compare the long-term effects of the angiotensin-convert ing enzyme (ACE)-inhibitor quinapril and the cardioselective beta-adre nergic blocking agent metoprolol on glycaemic control, with glycosylat ed haemoglobin (HbA(1c)) as the principal variable, in non-insulin-dep endent diabetes mellitus (NIDDM) patients with hypertension. Design. A randomized, double-blind, double-dummy, multicentre study during 6 mo nths preceded by a 4 week wash-out and a 3 week run-in placebo period. Quinapril (20 mg) and metoprolol (100 mg, conventional tablets) were given once daily. No change was made in the treatment of diabetes (die t and hypoglycaemic agents). Subjects, Seventy-two patients fulfilling the criteria were randomized and entered the double-blind period. Twe lve patients did not complete the study. Sixty patients, 26 on quinapr il and 34 on metoprolol, were available for the final analysis. Main o utcome measures. The effect was assessed by changes in HbA(1c), the fa sting serum glucose and the post-load serum glucose, C-peptide and ins ulin levels during the oral glucose tolerance test. Results. In the qu inapril group, the fasting serum glucose, oral glucose tolerance and t he C-peptide and insulin responses, determined as the incremental area under the curves (AUC), showed no change, but the mean HbA(1c) level increased from 6.2 +/- 1.1% to 6.5 +/- 1.3% (P < 0.05). In the metopro lol group, the rise in the mean level of HbA(1c), from 6.3 +/- 1.0% to 6.8 +/- 1.3% (P < 0.01), tended to be more marked than after quinapri l, although there was no significant difference between the increments . The mean fasting serum glucose showed an increase from 9.1 +/- 1.9 m M to 10.1 +/- 2.8 mM (P < 0.01) which correlated significantly with th e duration of diabetes (P < 0.01) and the increase in fasting serum tr iglycerides (P < 0.001). Moreover, in the metoprolol group we found si gnificant decreases in the oral glucose tolerance as well as C-peptide and insulin responses to the glucose load. Conclusions. Treatment wit h quinapril for 6 months appears to have advantages over metoprolol in NIDDM patients with hypertension. Although treatment with quinapril o r metoprolol over 6 months was concomitant with a rise in the HbA(1c), increased fasting blood glucose, decreased oral glucose tolerance and decreased C-peptide and insulin responses to a glucose challenge were observed only in patients treated with metoprolol.