Spironolactone reduces disease and death in patients with severe congestive heart failure and is well tolerated with regard to renal function and serum potassium concentrations.
1Guidelines recommend taking spironolactone in addition to angiotensin converting enzyme inhibitors and blockers, 2 3 but since spironolactone can lead to renal dysfuction or hyperkalaemia, we followed up a cohort of patients taking spironolactone to identify predictors of harmful effects.
Participants, methods, and resultsWe selected 125 consecutive patients from the congestive heart failure outpatient clinic of Frederiksberg University Hospital, Copenhagen (table). 4 We included only patients with a left ventricular ejection fraction (LVEF) of no more than 45% or patients who were taking spironolactone. We started 65 patients on spironolactone; 60 patients were already taking spironolactone when they were referred. We measured blood electrolytes at baseline and then every two months. The study started in September 1999 and lasted 2 years. We analysed data using 2 tests, Student's t tests, and multiple logistic regression.At baseline, 93 (74%) patients were receiving potassium supplementation. We stopped supplements in 66 (71%) patients and gradually reduced dosages in the others. We observed each patient for a mean 370 days; total observation was for 73.0 patient years. We saw each patient a mean 11.1 times (mean 22.9 days between visits).Mean peak serum creatinine concentration was 167.6 (SD 11.9) mol/l, and mean peak potassium serum concentration was 5.0 (0.4) mmol/l. A total of 73 (58%) patients, had serum creatinine > 130 mol/l, and 23 (18%) had > 220 mol/l. Relative to baseline, 69 (55%) patients had their serum creatinine concentrations increase by 20%, 30 (24%) by 50%, and 11 (9%) by 100%. A total of 45 (36%) patients had potassium serum concentrations > 5 mmol/l, 21 (17%) patients > 5.5 mmol/l, and 13 (10%) > 6 mmol/l.Patients taking spironolactone before referral did not differ significantly from those we started at the clinic in terms of severe hyperkalaemia (8.3% v 10.8%, P = 0.63) or azotaemia (23.3% v 24.6%, P = 0.81). We found a mean weight loss of 1.3 kg.We logistically regressed azotaemia (defined as a 50% increase in serum creatinine concentration) with age, sex, New York Heart Association function class (NYHAFC), LVEF, and use of angiotensin converting enzyme inhibitors and blockers. Age (odds ratio 1.74 (95% confidence interval 1.03-2.91) for each Baseline characteristics of the heart failure population studied (n=125)
Characteristic ValueMean (
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.