NCT02351973

Comparison of Single and Combination Diuretics in Low-Renin Hypertension

• Status: Unknown
• Phase: Phase 4
• Study type: Interventional
• Enrollment: 423 (actual)
• Sponsor: University of Cambridge · Academic / Other
• Sex: All
• Age: 18 Years – 80 Years
• Healthy volunteers: Not accepted

Summary

The purpose of this study is to determine whether the routine combination of optimal thiazide and K+-sparing diuretic will both increase efficacy of BP reduction and reduce risk of glucose intolerance; and whether K+-sparing diuretics alone may have a neutral or even beneficial effect upon glucose tolerance.

Detailed description

A major attraction of K+-sparing diuretics may be the absence of risk of new-onset diabetes (DM). Since they have not been compared in hypertension outcome trials, and DM has not been an endpoint in heart failure studies of spironolactone or eplerenone, we do not know for certain whether they are clean in this respect. Short-term studies suggest they are.49 Interestingly in INSIGHT there was no excess of DM in patients receiving HCTZ 25mg, which was combined with amiloride 2.5mg, but increased by 30% in patients on HCTZ/amiloride 50/5mg.44 In the proposed study we shall use the oral glucose tolerance test (OGTT) to provide an endpoint for each subject. This strategy has recently been employed to demonstrate a difference after just 12 weeks of dosing with a thiazide diuretic50. Hyperkalaemia has been the traditional concern about K+-sparing diuretics. We expect to demonstrate that in patients with eGFR ≥45, the risk of hyperkalaemia is nullified by combination with a thiazide. Instead then of amiloride being used mainly in trace doses to balance the hypokalaemia of thiazides, practice might reverse to thinking of thaizides as the "partner" used to negate risk of hyperkalaemia. The challenge to designing this study is to compare several options among the diuretics while achieving clear cut answers to: 1. the comparison of combination with single diuretics and 2. the comparison of K+-sparing diuretics with thiazide. A study of sufficient duration to establish efficacy and tolerability (especially upon glucose tolerance) cannot be crossover in design and therefore requires a large number of subjects to compare the options. In order to maximize recruitment whilst also maximizing sensitivity to detect changes in OGTT, we will open the trial to most of those patients with hypertension in whom diuretic is a reasonable next option, providing they have one feature of the metabolic syndrome - additional to hypertension.

Conditions

• Hypertension

Interventions

Type	Name	Description
DRUG	Hydrochlorthiazide	HCTZ 25mg to 50mg All drugs will be provided in an acceptable container where the active agent is not identified on the drug label. In Phase 1 (weeks 0-12) patients will have 1 tablet from each of 2 bottles. These will contain either a) HCTZ 12.5mg in both bottles; b) amiloride 5mg in both bottles; OR c) one bottle of each. In Phase 2 (weeks13-24) patients will take 2 tablets from each of 2 bottles. These bottles will have the same contents as in Phase 1, except that the number of tablets will be twice as many.
DRUG	Amiloride	Amiloride 10mg to 20mg All drugs will be provided in an acceptable container where the active agent is not identified on the drug label. In Phase 1 (weeks 0-12) patients will have 1 tablet from each of 2 bottles. These will contain either a) HCTZ 12.5mg in both bottles; b) amiloride 5mg in both bottles; OR c) one bottle of each. In Phase 2 (weeks13-24) patients will take 2 tablets from each of 2 bottles. These bottles will have the same contents as in Phase 1, except that the number of tablets will be twice as many.
DRUG	Hydrochlorthiazide and Amiloride	HCTZ 12.5 to 25mg \& + Amiloride 5mg to 10mg All drugs will be provided in an acceptable container where the active agent is not identified on the drug label. In Phase 1 (weeks 0-12) patients will have 1 tablet from each of 2 bottles. These will contain either a) HCTZ 12.5mg in both bottles; b) amiloride 5mg in both bottles; OR c) one bottle of each. In Phase 2 (weeks13-24) patients will take 2 tablets from each of 2 bottles. These bottles will have the same contents as in Phase 1, except that the number of tablets will be twice as many.

Timeline

• Start date: 2009-11-01
• Primary completion: 2015-07-01
• Completion: 2015-08-01
• First posted: 2015-01-30
• Last updated: 2015-07-03

Locations

1 site across 1 country: United Kingdom