Diabetes Care, Vol 21, Issue 4 574-579, Copyright © 1998 by American Diabetes Association
Response to intensive therapy steps and to glipizide dose in combination with insulin in type 2 diabetes. VA feasibility study on glycemic control and complications (VA CSDM)
C Abraira, WG Henderson, JA Colwell, FQ Nuttall, JP Comstock, NV Emanuele, SR Levin, CT Sawin and CK Silbert
DVA Cooperative Studies Center, Hines, Illinois 60141, USA.
OBJECTIVE: The feasibility study for the VA Cooperative Study on Glycemic
Control and Complications in Type 2 Diabetes (VA CSDM) prospectively
studied 153 insulin-requiring type 2 diabetes patients, randomized between
an intensively treated arm and a standard treatment arm during a mean
follow-up of 27 months. The glycemic response to each of the progressive,
sequential phases of insulin treatment was assessed, along with the
incidence of hypoglycemic reactions and the relative efficacy of different
doses of glipizide in combination with fixed doses of insulin. RESEARCH
DESIGN AND METHODS: Five medical centers participated; half of the patients
were assigned to the intensive treatment arm aiming for normal HbA1c
levels. Age of patients was 60 +/- 6 years, duration of diabetes 8 +/- 3
years, and BMI 30.7 +/- 4 kg/m2. A four-step management technique was used,
with patients moving to the next step if the operational goals were not
met: Phase I, evening intermediate or long-acting insulin; phase II, added
day-time glipizide; phase III, two injections of insulin alone; and phase
IV, multiple daily insulin injections. Home glucose monitoring measurements
were done twice daily and at 3:00 A.M. once a week. Hypoglycemic reactions
and home glucose monitoring results were recorded and counted in each of
the treatment phases. RESULTS: Baseline HbA1c was 9.3 +/- 1.8%, and fasting
plus serum glucose was 11.4 +/- 3.3 mmol/1. Fasting serum glucose fell to
near normal in phase I, and remained so in the other treatment phases. An
HbA1c separation of 2.1% between the arms was maintained during the course
of the study, while the intensive arm kept HbA1c levels below 7.3% (P =
0.001). Most of the decrease in HbA1c occurred with one injection of
insulin alone (phase I, -1.4%) or adding day-time glipizide (phase II,
-1.9% compared with baseline). HbA1c did not decrease further after
substituting two injections of insulin alone, with twice the insulin dose.
Multiple daily injections resulted in an additional HbA1c fall (-2.4%
compared with baseline). However, two-thirds of the patients were still on
one or two injections a day at the end of the study. Changes in home
glucose monitoring levels paralleled those of the HbA1c, as did the
increments in number of reported hypoglycemic reactions, virtually all
either "mild" or "moderate" in character. For the combination of glipizide
and insulin (phase II), the only significant effect was obtained with daily
doses up to 10 mg a day; there were no significant additional benefits with
up to fourfold higher daily doses, and HbA1c levels had an upward trend
with doses > 20 mg/day. CONCLUSIONS: A simple regime of a single
injection of insulin, alone or with glipizide, seemed sufficient to obtain
clinically acceptable levels of HbA1c for most obese, insulin-requiring
type 2 diabetes patients. Further decrease of HbA1c demanded multiple daily
injections at the expense of doubling the insulin dose and the rate of
hypoglycemic events. In combination therapy, doses of glipizide > 20
mg/day offered no additional benefit.