Serum magnesium aberrations in furosemide (frusemide) treated patients with congestive heart failure: pathophysiological correlates and prognostic evaluation.
OBJECTIVE
To determine the prevalence of hypomagnesaemia and hypermagnesaemia, to discern various factors associated with abnormal serum magnesium, and to estimate prognostic significance of serum magnesium aberrations in patients with congestive heart failure.


METHODS
Observational study.


METHODS
Medical department of a university hospital (tertiary referral centre).


METHODS
404 consecutive patients admitted with congestive heart failure as one of the diagnoses and previously treated with furosemide (frusemide) for at least three months.


METHODS
Clinical, biochemical, and electrocardiographic variables were analysed with respect to serum magnesium aberrations. Following discharge, mortality rates, including sudden death, were registered.


RESULTS
Hypomagnesaemia was found in 50 patients (12.3%) and 20 (4.9%) were hypermagnesaemic. Female sex (p < 0.04), diabetes mellitus (p < 0.006), hypocalcaemia (p = 0.03), hyponatraemia (p < 0.05), malignant disease (p = 0.05), and high fever (p = 0.05) were statistically associated with hypomagnesaemia. Renal failure, severe congestive heart failure, and high dose furosemide treatment (> 80 mg/day) were associated with hypermagnesaemia (p < 0.001, p = 0.05, and p < 0.03, respectively). Hypermagnesaemic patients were older and weighed less. On follow up (median duration 43 months), 169 (41.8%) died, with 22 (13%) sudden deaths. Mortality was highest with hypermagnesaemia, lowest with normomagnesaemia, and intermediate with hypomagnesaemia. After adjustment for renal failure, old age, and severity of congestive heart failure, hypomagnesaemia but not hypermagnesaemia emerged as being significantly associated with shorter survival (p = 0.009). No statistical association was found between sudden death and magnesium concentrations.


CONCLUSIONS
While hypermagnesaemia seems to represent a prognostic marker only, hypomagnesaemia appears to have an adverse pathophysiological effect. The subgroup of patients at risk for hypomagnesaemia requires frequent serum magnesium determinations and magnesium replacement for as long as hypomagnesaemia persists.
Cohen
N
N
Department of Internal Medicine F, Assaf Harofeh Medical Centre, Tel-Aviv University, Zerifin, Israel. internal6@asaf.health.gov.il
Almoznino-Sarafian
D
D
Zaidenstein
R
R
Alon
I
I
Gorelik
O
O
Shteinshnaider
M
M
Chachashvily
S
S
Averbukh
Z
Z
Golik
A
A
Chen-Levy
Z
Z
Modai
D
D
D000368:Aged; D004232:Diuretics / Q000627:therapeutic use*; D005260:Female; D005665:Furosemide / Q000627:therapeutic use*; D006333:Heart Failure / Q000097:blood / Q000188:drug therapy* / Q000401:mortality; D006801:Humans; D008274:Magnesium / Q000097:blood*; D008275:Magnesium Deficiency / Q000097:blood / Q000150:complications*; D008297:Male; D011379:Prognosis; D012307:Risk Factors; D016019:Survival Analysis
D004232:Diuretics; D005665:Furosemide; D008274:Magnesium