Longitudinal Change in HbA1c in Patients with Type 2 Diabetes: Comparison of Short-acting, Biphasic and Basal Insulin

Abstract

Objective: To evaluate the annual change in HbA1c values among patients with type 2 diabetes in primary care practices comparing different insulin regimens.

Research Design and Methods: Longitudinal data from 666 nationwide general and internal medicine practices in Germany (Disease Analyser, IMS HEALTH) from 7/2004 to 6/2006 were analysed, including 348 patients (mean age±SD: 61±11 years) with continuous short-acting (regular insulin or analogues), 1 906 with biphasic (72±9 years), 439 with basal-bolus (68±10 years), and 1 719 with basal insulin therapy (65±10 years). The mean of the individual relative changes in HbA1c (level in 2006 divided by level in 2005) were compared between insulin groups, adjusting for age, sex, BMI, diabetes duration, oral antidiabetics, comorbidity, health insurance, visits, hospitalisations, and practice type using general linear models.

Results: There was only a small difference in baseline HbA1c values (range 7.3–7.5%) between the four insulin groups (p=0.008). Substantial group differences were observed for age, diabetes duration, and additional prescriptions of oral antidiabetics (p<0.0001). After adjusting for potential confounders, the relative annual increase in HbA1c was highest for biphasic insulin (1.021; 95%CI 1.016–1.025), followed by basal-bolus therapy (1.017; 1.012–1.022), and basal insulin (monotherapy) (1.012; 1.002–1.021). No significant change in HbA1c was found for short-acting insulin (1.006; 0.996–1.016).

Conclusions: Although many options for insulin therapy are now available, a progression of glycemia still occurs in the majority of insulin-treated type 2 diabetic patients in primary care.

Key words

type 2 diabetes - insulin treatment - general practice - HbA1c - glycemic control

References

• 1 UK Prospective Diabetes Study (UKPDS) Group. . Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33).  Lancet. 1998;  352 837-853
• 2 DeWitt DE, Hirsch IB. Outpatient insulin therapy in type 1 and type 2 diabetes mellitus. Scientific review.  JAMA. 2003;  289 2254-2264
• 3 Levy P. Insulin analogs or premixed insulin analogs in combination with oral agents for treatment of type 2 diabetes.  Med Gen Med. 2007;  9 12
• 4 Holman RR, Thorne KI, Farmer AJ. et al . Addition of biphasic, prandial, or basal insulin to oral therapy in type 2 diabetes.  N Engl J Med. 2007;  357 1716-1730
• 5 Rathmann W, Kostev K, Haastert B. Glycemic durability of oral antidiabetic agents.  N Engl J Med. 2007;  356 1378-1379
• 6 Rathmann W, Haastert B, Icks A. et al . Trends in outpatient prescription drug costs in diabetic patients in Germany, 1994–2004.  Diabetes Care. 2007;  30 848-853
• 7 Hauner H, Köster I, Ferber L von. Ambulante Versorgung von Patienten mit Diabetes mellitus im Jahr 2001.  Dtsch Med Wochenschr. 2003;  128 2638-2643
• 8 Pittrow D, Stalla GK, Zeiher AM. et al . Prävalenz, medikamentöse Behandlung und Einstellung des Diabetes mellitus in der Hausarztpraxis.  Med Klin. 2006;  101 635-644
• 9 Liebl A, Neiss A, Spannheimer A. et al . Complications, co-morbidity, and blood glucose control in type 2 diabetes mellitus patients in Germany – results from the Code-2 study.  Exp Clin Endocrinol Diabetes. 2002;  110 10-16
• 10 Rothenbacher D, Rüter G, Saam S. et al . Versorgung von Patienten mit Typ 2-Diabetes. Ergebnisse aus 12 Hausarztpraxen.  Dtsch Med Wochenschr. 2002;  127 1183-1187
• 11 Monnier L, Lapinski H, Colette C. Contribution of fasting and postprandial plasma glucose increments to the overall diurnal hyperglycemia of type 2 diabetic patients: variations with increasing levels of HbA(1c).  Diabetes Care. 2003;  26 881-885
• 12 MacMahon GT, Dluhy RG. Intention to treat – initiating insulin and the 4-T study.  N Engl J Med. 2007;  357 1759-1761
• 13 Vähätalo M, Rönnemaa T, Viikari J. Recognition of fasting or overall hyperglycaemia when starting insulin treatment in patients with type 2 diabetes in general practice.  Scand J Prim Health Care. 2007;  25 147-153
• 14 Nelson SE, Palumbo PJ. Addition of insulin to oral therapy in patients with type 2 diabetes.  Am J Med Sci. 2006;  331 257-263
• 15 Fritsche A, Schmülling RM, Häring HU. et al . Intensive insulin therapy combined with metformin in obese type 2 diabetic patients.  Acta Diabetol. 2000;  37 13-18

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