Plain English Summary
Background and study aims
Chronic kidney disease (CKD) is a major risk factor for heart and blood vessel disease. Mild CKD is surprisingly common, affecting almost 1 in 7 of the population. The adverse cardiovascular (heart) effects of CKD are caused mainly by damage and thickening of the heart muscle and an increase in artery stiffness, which together cause stroke, heart failure and sudden cardiac death. We have previously shown that an old and inexpensive drug called spironolactone reduces the heart thickening and arterial stiffening in CKD compared to an inactive (placebo) tablet. During treatment with spironolactone however, blood pressure fell and it is not clear whether the beneficial effects of this drug on the heart and arteries were caused by this fall in blood pressure or were specific to the effects of spironolactone. The aim of this study is to compare the effects of spironolactone to a different blood pressure lowering drug called chlortalidone on patients with early CKD.
Who can participate?
Patients aged over 18 with early CKD
What does the study involve?
Participants are randomly allocated to take either spironolactone or chlortalidone for 40 weeks. Changes in heart muscle weight and arterial stiffness are measured.
What are the possible benefits and risks of participating?
The results should show whether or not the effects of spironolactone on the arteries and heart in patients with CKD are due to blood pressure lowering alone or are due to the special effects of spironolactone. If the effects are specific to spironolactone and occur over and above the blood pressure lowering effects, the drug may be a very effective and inexpensive way to prevent death and disability due to heart and artery disease in patients with CKD.
Where is the study run from?
Birmingham Clinical Trials Unit (UK)
When is the study starting and how long is it expected to run for?
January 2014 to January 2017
Who is funding the study?
British Heart Foundation (BHF) (UK)
Who is the main contact?
Ms Gemma Slinn
Birmingham Clinical Trials Unit
Division of Cancer Studies
Robert Aitken Institute
A randomised multicentre open-label blinded end point trial to compare the effects of spironolactone to chlortalidone on left ventricular mass and arterial stiffness in stage 3 chronic kidney disease
SPIRO - CKD
Chronic kidney disease (CKD) is a major but poorly recognised risk factor for heart and blood vessel disease. Mild CKD is surprisngly common affecting almost 1 in 7 of the population. The adverse cardiovascular effects of CKD are caused mainly by damage and thickening of heart muscle and an increase in artery stiffness which together cause stroke, heart failure and sudden cardiac death. We have previously shown that an old and inexpensive drug called spironolactone reduces the heart thickening and arterial stiffening in CKD compared to an inactive placebo tablet. During treatment with spironolactone however, blood pressure fell and it is not clear whether the beneficial effects of this drug on the heart and arteries were caused by this fall in blood pressure or were specific to the effects of spironolactone.
13/WM/0304; First MREC approval date 09/09/2013
Randomised; Interventional; Design type: Not specified, Treatment
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use contact details to request a participant information sheet
Topic: Cardiovascular, Renal and Urogenital; Subtopic: Cardiovascular (all Subtopics), Renal and Urogenital (all Subtopics); Disease: Cardiovascular, Renal
Participants are randomly allocated to treatment with either spironolactone (25 mg od.) or chlortalidone (half a 50 mg tablet od.) for 40 weeks.
12-lead ECG: 12-lead ECG to be performed at the screening visit according to standard clinical practice. The primary function of the ECG is to detect any evidence of Q-wave myocardial infarction or atrial fibrillation (which would exclude the participant from the study).
Ambulatory BP: A mobilograph will be used to record 24 hour brachial and central blood pressure, cardiac output and other indices derived from pulse wave analysis; Arterial haemodynamics, SphygmoCor system to be used to record central blood pressure and arterial stiffness.
Cardiac MRI scan: CMR scans will be performed at the randomisation/baseline visit and visit 6
Laboratory assessments: Standard clinical lab investigations done at: screening visit; visit 3; visit 6.
Additional clinical lab investigations for renal function and safety to be done at: randomisation visit; visit 1; visit 2; visit 4 and visit 5.
Blood and urine for cardiovascular biomarkers to be taken at: randomisation visit; visit 3; visit 5; visit 6 and visit 7
Primary outcome measures
Change between baseline and 40 weeks in arterial stiffness measured by carotid-femoral PWV; Timepoint(s): 40 weeks
Secondary outcome measures
1. Change between baseline and 40 weeks in blood pressure; Timepoint(s): 40 weeks
2. Change between baseline and 40 weeks in LV mass measured by cardiac MRI (co-primary outcome); Timepoint(s): 40 weeks
3. Change between baseline and 40 weeks in urinary albumin:creatinine ratio; Timepoint(s): 40 weeks
4. Changes between baseline and 40 weeks in plasma NT-pro-BNP therapy; Timepoint(s): 40 weeks
5. Changes in plasma NT-pro-BNP and arterial stiffness measures; Timepoint(s): 24 weeks
6. Decline in renal function (requiring discontinuation from trial therapy); Timepoint(s): 40 weeks
7. Incidence of hyperkalaemia; Timepoint(s): 46 weeks
8. Incidence of side-effects (requiring discontinuation from trial therapy); Timepoint(s): 40 weeks
9. Symptomatic hypotension (requiring discontinuation from trial therapy); Timepoint(s): 40 weeks
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Aged over 18 years
2. Diagnosis of stage 3 CKD [estimated glomerular filtration rate (eGFR) by 4 variable Modification of Diet in Renal Disease (MDRD) of 3059ml/min/1.73m2 on 2 occasions, at least 3 months apart]
3. Well controlled blood pressure (office reading of <150/90 mmHg, i.e. within 10 mmHg of the systolic level recommended in the Renal Association Clinical Practice Guideline, Fifth edition)
4. On established (>6 weeks) treatment with angiotensin-converting-enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs)
5. Written informed consent
Target number of participants
Planned Sample Size: 350; UK Sample Size: 350;
Participant exclusion criteria
1. Diabetes mellitus
2. Clinical evidence of hypovolaemia
3. Recent (<6 months) acute myocardial infarction or other major adverse cardiovascular event
4. Established diagnosis of left ventricular dysfunction or heart failure
5. Active malignant disease with a life expectancy of <5 years
6. Previous hyperkalaemia (K+ =6.0 mmol/l without precipitating cause)
7. Serum K+ =5.0 mmol/l at entry
8. Serum sodium <132 mmol/l at entry
9. Atrial fibrillation on screening ECG
10. Use of a thiazide or loop diuretic in the 6 weeks prior to enrolment
12. Known alcohol or drug abuse
13. Active chronic diarrhoeal illness
14. Recent active gout (within 3 months)
15. Episode of acute kidney injury within 3 months
16. Documented Addisons disease
17. Current treatment with fludrocortisone or cotrimoxasole
18. Office blood pressure <115 mmHg systolic or <50 mmHg diastolic
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Birmingham Clinical Trials Unit
British Heart Foundation (BHF) (UK); Grant Codes: SP/12/8/29620
Funding Body Type
private sector organisation
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting