Assessment of serum creatinine and kidney function among incident metformin users.
OBJECTIVE
Metformin is considered the first-line antihyperglycemic therapy for type 2 diabetes, but should be used with caution in people with renal insufficiency. Our study objective was to describe the proportion of patients who have an assessment of kidney function (serum creatinine [SCr] and estimated glomerular filtration rate [eGFR]) around the time of initiation of metformin in new users.


METHODS
We used data from the Alberta Kidney Disease Network to identify patients with diabetes (age, ≥66 y) with a new prescription for metformin from November 1, 2002, to March 31, 2008. We assessed whether SCr measurement was completed before and after metformin initiation. The eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and categorized into CKD stages. Frequency of metformin use based on SCr measurement and CKD stage was reported using descriptive statistics.


RESULTS
A total of 22 051 subjects were identified as new metformin users. Overall, 25.4% (n=5608) had no measurement of SCr or assessment of eGFR before metformin prescription. In addition, of patients with an eGFR measurement, 38.7% (n=8544) of individuals had an eGFR of less than 60 mL/min/1.73 m(2).


CONCLUSIONS
One quarter of patients started on metformin did not have a SCr measurement completed beforehand. Also, metformin was used commonly among patients with diabetes and CKD, potentially putting these individuals at risk for adverse events.
Department of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland.
Melissa
M
Schorr
Department of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada.
Brenda R
BR
Hemmelgarn
Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
Marcello
M
Tonelli
Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada.
Andrea
A
Soo
Department of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada.
Braden J
BJ
Manns
Department of Medicine, University of Calgary, Calgary, Alberta, Canada. Electronic address: lauren.bresee@albertahealthservices.ca.
Lauren C
LC
Bresee
D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D000075202:Contraindications; D003404:Creatinine / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007677:Kidney Function Tests; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000503:physiopathology*
D007004:Hypoglycemic Agents; D008687:Metformin; D003404:Creatinine
créatinine sérique; diabetes; diabète; estimated glomerular filtration rate; estimation du débit de filtration glomérulaire; metformin; metformine; serum creatinine