Contra-indications to metformin therapy are largely disregarded.
OBJECTIVE
To investigate the current metformin treatment practice and in particular to examine the consideration given to its contraindications.


METHODS
A cross-sectional analysis of 308 consecutive Type 2 diabetic patients (mean age 66+/-11.3 years) previously treated with metformin on an outpatient basis and admitted to a German general hospital during the period from 1 January 1995 to 31 May 1998 because of acute disease or in order to optimize their diabetes management. All patients underwent a basic investigation comprising a documentation of their medical history, a physical examination, an electrocardiogram, and an extensive laboratory profile; 34% also had acute coronary angiography.


RESULTS
On admission to hospital, 73% of the patients were found to have contra-indications, risk factors, or intercurrent illnesses necessitating discontinuation of metformin; 51% of these patients had several of these conditions. As major contra-indications to metformin, renal impairment was present in 19% of all patients, heart failure in 25%, respiratory insufficiency in 6.5%, and hepatic impairment in 1.3%. The risk factors to metformin included advanced coronary heart disease in 51%, atrial fibrillation in 9.8%, chronic alcohol abuse in 3.3%, advanced peripheral vascular disease in 2%, and pregnancy in 0.7%. As intercurrent illnesses, cerebral ischaemia occurred in 9.8% under metformin treatment and malignancies were diagnosed in 6.5%. The patients with contra-indications or requiring caution to metformin were significantly older and had previously been treated with more cardiovascular medication than those without such reservations (P<0.001).


CONCLUSIONS
Despite the considerable risk of lactic acidosis in the majority of patients, no cases were observed.
Holstein
A
A
1st Department of Medicine, Klinikum Lippe-Detmold, Germany.
Nahrwold
D
D
Hinze
S
S
Egberts
E H
EH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000075202:Contraindications; D003327:Coronary Disease / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000453:epidemiology; D003929:Diabetic Neuropathies / Q000453:epidemiology; D005260:Female; D005858:Germany; D006331:Heart Diseases / Q000453:epidemiology; D006760:Hospitalization / Q000706:statistics & numerical data*; D006769:Hospitals, General / Q000706:statistics & numerical data; D006801:Humans; D007004:Hypoglycemic Agents; D008297:Male; D008687:Metformin; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000453:epidemiology; D012131:Respiratory Insufficiency / Q000453:epidemiology; D012307:Risk Factors
D007004:Hypoglycemic Agents; D008687:Metformin