Endocrine Abstracts

Background: We assessed the effects of hydrochlorothiazide given alone and in combination with an ACEI on β-cell function in a negroid population to further explore possible ethnic differences in the effect of antihypertensive drugs on HOMA-IR.

Materials and methods: Eighty newly diagnosed Nigerian essential hypertensive patients were assigned to receive either hydrochlorothiazide 25 mg daily or both hydrochlorothiazide and lisinopril (25/10 mg daily) in an open label study for a period of 12 weeks. The treatment groups were well matched in clinical and demographic baseline features. Changes in HOMA-IR from baseline to end of study (week 12), fasting plasma glucose, potassium, serum insulin, and blood pressure over the same period were also evaluated.

Results: After 12 weeks, there was no statistically significant difference in delta HOMA-IR between the two groups; Blood pressure reduction was similar in both groups; mean reduction in systolic blood pressure was 17.8±10.8 mmHg vs 18.1±15.3 mmHg and diastolic blood pressure was 10.6±7.0 mmHg vs 8.8±12.7 mmHg (P>0.05) for HCT monotherapy and HCT–lisinopril combination groups respectively.

Conclusions: HCT monotherapy in hypertensive indigenous Nigerians, was not associated with worse metabolic effects when compared with combination therapy using lisinopril, an ACE inhibitor after 12 weeks. Low dose thiazide diuretic as first-line antihypertensive medication may be safe in the short term, further larger and long-term studies are needed to corroborate this finding. The possibility that concurrent ACE inhibitor therapy mitigates and thiazide induced increase in insulin resistance, requires further study as well.