Insulin & C-peptide levels in sulfonylurea-induced hypoglycemia: a systematic review.
OBJECTIVE
We will describe insulin and C-peptide levels observed in sulfonylurea-induced hypoglycemia and determine whether these levels differed if obtained before or after hypoglycemic therapy.


METHODS
We performed a systematic review of the English literature to identify Medline articles containing "sets" (glucose <60 mg/dL with insulin and C-peptide levels). These "sets" were categorized as being obtained BEFORE, AFTER, or UNKNOWN with respect to hypoglycemic therapy.


RESULTS
22 articles, 76 patients, and 97 "sets" were included. Mean glucose (mg/dL), insulin (muIU/mL), and C-peptide (ng/mL) for all "sets' were 28.6 (+/-12.6; 26.1 to 31.2), 54.4 (+/-126.3; 28.3 to 80.5), 7.2 (+/-6.2; 5.9 to 8.5). The BEFORE measures were 24.3 (+/-7.3; 18.7 to 30.0), 36.6 (+/-26.2; 16.5 to 56.7), 5.4 (+/-4.6; 1.5 to 9.2). The AFTER measures were 33.1 (+/-9.8; 28.2 to 38.0), 126.7 (+/-278.1; 0 to 265.0), 10.3 (+/-10.5; 5.1 to 15.4). The UNKNOWN measures were 28.0 (+/-13.5; 24.7 to 31.3), 37.1 (+/-21.8; 31.7 to 42.5), 6.5 (+/-4.3; 5.4 to 7.6). Only one "set" (glucose 49 mg/dL) had insulin <3.9 muIU/mL and C-peptide <1.4 ng/mL.


CONCLUSIONS
Insulin > or =3.9 muIU/mL, C-peptide > or =1.4 ng/mL, and glucose <49 mg/dl are consistent with sulfonylurea-induced hypoglycemia. BEFORE levels were lower, but they were consistent with sulfonylurea-induced hypoglycemia.
DeWitt
Christopher R
CR
Saint Paul's Hospital, Division of Emergency Medicine, Vancouver, BC, Canada. cdewittmd@yahoo.com <cdewittmd@yahoo.com>
Heard
Kennon
K
Waksman
Javier C
JC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000187:drug effects*; D002096:C-Peptide / Q000097:blood*; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000139:chemically induced*; D007004:Hypoglycemic Agents / Q000009:adverse effects*; D007231:Infant, Newborn; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D013453:Sulfonylurea Compounds / Q000009:adverse effects*; D015854:Up-Regulation
D001786:Blood Glucose; D002096:C-Peptide; D007004:Hypoglycemic Agents; D007328:Insulin; D013453:Sulfonylurea Compounds