Trial · NCT01973335

Acetazolamide and Spironolactone to Increase Natriuresis in Congestive Heart Failure

NCT01973335, Phase 4, Completed, Hasselt University; results first posted 2019-03-21

3 sourcestrials-2026-11-12-0.5.0

Cite this record

ConductScience Library. Acetazolamide and Spironolactone to Increase Natriuresis in Congestive Heart Failure. Trials, record NCT01973335. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT01973335

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Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: Acetazolamide and Spironolactone to Increase Natriuresis in Congestive Heart Failure
NCT number: NCT01973335
Status: Completed
Phases: Phase 4
Enrollment: 34 participants, actual
Lead sponsor: Hasselt University
Conditions: Heart Failure
Interventions: Combination therapy with acetazolamide and low-dose loop diuretics, High-dose loop diuretics, Upfront therapy with oral spironolactone
First posted: 2013-10-31
Last updated: 2019-05-21
Results first posted: 2019-03-21
Limitations and caveats: Slow recruitment: switch from monocentric to 2-center study; longer than anticipated duration of the study; eventually termination of the study after only 34 of the originally intended 80 patients had been included resulting in an underpowered study.

Source ClinicalTrials.gov

Registered outcomes21

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Acetazolamide Arm: Natriuresis 24 h	24h	For the acetazolamide arm of the study, the primary end-point is total natriuresis after 24 h (mmol). To assess this, urine is collected for 24 h after the first administration of diuretics according to the study protocol and natriuresis is calculated as the total amount of diuresis (L) multiplied by the urinary sodium concentration (mmol/L). Subsequently, patients receiving acetazolamide and low-dose loop diuretics (both the groups with and without upfront spironolactone together) are compared to patients not receiving acetazolamide but high-dose loop diuretics instead (both the groups with or without upfront spironolactone together)
Primary	Spironolactone Arm: Incidence of Hypo- (Serum Potassium <3.5 mmol/L) or Hyperkalemia (Serum Potassium >5.0 mmol/L)	72h	For the spironolactone arm of the study, the primary end-point is the incidence of either hypo- (serum potassium \<3.5 mmol/L) or hyperkalemia (serum potassium \>5.0 mmol/L) at any of 3 morning blood samples at consecutive days after randomization. Patients receiving upfront spironolactone (both the group receiving acetazolamide+low dose loop diuretics and the group receiving high-dose loop diuretic therapy) are compared with them receiving no spironolactone (both the group receiving acetazolamide+low dose loop diuretics and the group receiving high-dose loop diuretic therapy).
Secondary	NT-proBNP Change After 72 h	72h	Relative NT-proBNP change (%) after 72 h compared to baseline.
Secondary	Number of Participants With Worsening Renal Function	72h	Worsening renal function is defined as a rise in serum creatine \>0.3 mg/dL or a \>20% decrease in estimated glomerular filtration rate by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula compared to baseline at any time point before 72 h. Serum creatinine values are assessed at three consecutive mornings after study inclusion.
Secondary	Persistent Renal Impairment	4 weeks after hospital discharge	Persistent renal impairment is defined as a persistently elevated serum creatine \>0.3mg/dL or \>20% decrease in estimated glomerular filtration rate by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula, above the baseline value of the patient and will be assessed on a scheduled follow-up appointment 4 weeks after hospital discharge.
Secondary	Peak Plasma Aldosterone Concentration After 72 h	72h	At three consecutive mornings after study inclusion, blood samples will be taken to assess plasma aldosterone levels. The highest value will constitute the peak plasma aldosterone concentration (ng/L).
Secondary	Peak Plasma Renin Activity After 72 h	72h	At three consecutive mornings after study inclusion, blood samples will be taken to assess plasma renin activity. The highest value will constitute the peak plasma renin activity (ng/mL/h).
Other	Natriuresis 48 h	48h	Total natriuresis (mmol) after 48 h.
Other	Natriuresis 72 h	72h	Total natriuresis (mmol) after 72 h.
Other	Diuresis 24 h	24h	Total amount of urine output (L) after 24 h.

1 to 10 of 21Source ClinicalTrials.gov

See all 21 registered outcomes

Outcomes21

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Acetazolamide Arm: Natriuresis 24 h	24h	2 patients not analysed because of errors with 24 h urinary collection	mmol	MEAN
PRIMARY	Spironolactone Arm: Incidence of Hypo- (Serum Potassium <3.5 mmol/L) or Hyperkalemia (Serum Potassium >5.0 mmol/L)	72h		Participants	COUNT_OF_PARTICIPANTS
SECONDARY	NT-proBNP Change After 72 h	72h		percentage change from baseline	MEAN
SECONDARY	Number of Participants With Worsening Renal Function	72h		Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Persistent Renal Impairment	4 weeks after hospital discharge	9 patients died or were too sick for follow-up appointment; 9 refused a venous blood sample at the follow-up appointment (protocol violation)	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Peak Plasma Aldosterone Concentration After 72 h	72h		ng/L	MEDIAN
SECONDARY	Peak Plasma Renin Activity After 72 h	72h		µg/L/h	MEDIAN
OTHER_PRE_SPECIFIED	Natriuresis 48 h	48h
OTHER_PRE_SPECIFIED	Natriuresis 72 h	72h
OTHER_PRE_SPECIFIED	Diuresis 24 h	24h

1 to 10 of 21Source ClinicalTrials.gov

See all 21 outcomes

Results by group28

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Value	Spread	Units
Acetazolamide Arm: Natriuresis 24 h	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	324	Standard Deviation 133	mmol
Acetazolamide Arm: Natriuresis 24 h	High-dose Loop Diuretics, Upfront Spironolactone	300	Standard Deviation 165	mmol
Acetazolamide Arm: Natriuresis 24 h	Acetazolamide/Low-dose Loop Diuretics, no Spironolactone	211	Standard Deviation 96	mmol
Acetazolamide Arm: Natriuresis 24 h	High-dose Loop Diuretics, no Spironolactone	190	Standard Deviation 91	mmol
Spironolactone Arm: Incidence of Hypo- (Serum Potassium <3.5 mmol/L) or Hyperkalemia (Serum Potassium >5.0 mmol/L)	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	1		Participants
Spironolactone Arm: Incidence of Hypo- (Serum Potassium <3.5 mmol/L) or Hyperkalemia (Serum Potassium >5.0 mmol/L)	High-dose Loop Diuretics, Upfront Spironolactone	2		Participants
Spironolactone Arm: Incidence of Hypo- (Serum Potassium <3.5 mmol/L) or Hyperkalemia (Serum Potassium >5.0 mmol/L)	Acetazolamide/Low-dose Loop Diuretics, no Spironolactone	5		Participants
Spironolactone Arm: Incidence of Hypo- (Serum Potassium <3.5 mmol/L) or Hyperkalemia (Serum Potassium >5.0 mmol/L)	High-dose Loop Diuretics, no Spironolactone	2		Participants
NT-proBNP Change After 72 h	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	-20	Standard Deviation 36	percentage change from baseline
NT-proBNP Change After 72 h	High-dose Loop Diuretics, Upfront Spironolactone	-11	Standard Deviation 19	percentage change from baseline

1 to 10 of 28Source ClinicalTrials.gov

See all 28 results by group

Participant flow12

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Overall Study	STARTED	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	9
Overall Study	STARTED	High-dose Loop Diuretics, Upfront Spironolactone	7
Overall Study	STARTED	Acetazolamide/Low-dose Loop Diuretics, no Spironolactone	9
Overall Study	STARTED	High-dose Loop Diuretics, no Spironolactone	9
Overall Study	COMPLETED	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	9
Overall Study	COMPLETED	High-dose Loop Diuretics, Upfront Spironolactone	7
Overall Study	COMPLETED	Acetazolamide/Low-dose Loop Diuretics, no Spironolactone	9
Overall Study	COMPLETED	High-dose Loop Diuretics, no Spironolactone	9
Overall Study	NOT COMPLETED	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	0
Overall Study	NOT COMPLETED	High-dose Loop Diuretics, Upfront Spironolactone	0

1 to 10 of 12Source ClinicalTrials.gov

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Adverse events28

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk
other	Metabolic acidosis	Renal and urinary disorders	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	2	9
other	Metabolic acidosis	Renal and urinary disorders	High-dose Loop Diuretics, Upfront Spironolactone	3	7
other	Metabolic acidosis	Renal and urinary disorders	Acetazolamide/Low-dose Loop Diuretics, no Spironolactone	2	9
other	Metabolic acidosis	Renal and urinary disorders	High-dose Loop Diuretics, no Spironolactone	3	9
other	Moderate hyperkalemia	Renal and urinary disorders	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	0	9
other	Moderate hyperkalemia	Renal and urinary disorders	High-dose Loop Diuretics, Upfront Spironolactone	1	7
other	Moderate hyperkalemia	Renal and urinary disorders	Acetazolamide/Low-dose Loop Diuretics, no Spironolactone	2	9
other	Moderate hyperkalemia	Renal and urinary disorders	High-dose Loop Diuretics, no Spironolactone	0	9
other	Hypokalemia	Renal and urinary disorders	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	1	9
other	Hypokalemia	Renal and urinary disorders	High-dose Loop Diuretics, Upfront Spironolactone	1	7

1 to 10 of 28Source ClinicalTrials.gov

See all 28 adverse events

Adverse event totals12

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	6	9
Total, all-cause mortality	High-dose Loop Diuretics, Upfront Spironolactone	5	7
Total, all-cause mortality	Acetazolamide/Low-dose Loop Diuretics, no Spironolactone	5	9
Total, all-cause mortality	High-dose Loop Diuretics, no Spironolactone	5	9
Total, other adverse events	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	6	9
Total, other adverse events	High-dose Loop Diuretics, Upfront Spironolactone	4	7
Total, other adverse events	Acetazolamide/Low-dose Loop Diuretics, no Spironolactone	7	9
Total, other adverse events	High-dose Loop Diuretics, no Spironolactone	5	9
Total, serious adverse events	Acetazolamide/Low-dose Loop Diuretics, Upfront Spironolactone	3	9
Total, serious adverse events	High-dose Loop Diuretics, Upfront Spironolactone	5	7

1 to 10 of 12Source ClinicalTrials.gov

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Papers2

The papers the trial lists on ClinicalTrials.gov.

PMID	Listed as	Source
29587582	RESULT	PubMed
31074184	RESULT	PubMed

Grants0

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

None in this release.

Trial comparisons0

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

None in this release.

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

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