Original researchInitiation of insulin among veterans with type 2 diabetes and sustained elevation of A1c
Introduction
Although considerable progress has been made in improving the overall quality of diabetes care, poor glucose control remains a concern [1], [2]. Glucose control is associated with both macro and micro-vascular complications [3], [4]. Besides patient adherence to diet and exercise behaviors by patients, glucose control also depends on adequate and timely initiation and intensification of therapy [5], [6], [7].
Of particular concern for type 2 diabetes (T2DM) care is initiating insulin therapy in a timely fashion [8], [9], [10], [11]. Patients who were newly diagnosed in the United Kingdom Prospective Diabetes Study had 50% of normal insulin secretion at diagnosis and less than 25% of normal insulin secretion within 6 years of diagnosis [4]. For many, if not most patients with T2DM, oral glucose-lowering agents eventually lose their effectiveness. Brown and colleagues found that among patients with persistent poor control (mean A1c 8.8 ± 1.2) and were treated by combination oral therapy before insulin initiation, 87.7% ended up on insulin therapy over an 8-year period [12]. Evidence suggests that delay in insulin initiation is attributed to the reluctance from both the physician and the patient [9], [13], [14], [15].
Adequate control of T2DM is a priority in the Veterans Health Administration (VHA). Approximately 26% of veterans have a diagnosis of T2DM. T2DM is the third most common diagnosis in VHA, and it accounts for over 25% of pharmacy costs and over 1.7 million hospital bed days [16]. The VHA has specific clinical practice guidelines for T2DM management with algorithms for medication intensification regarding glucose control. Although VHA guidelines are clear about insulin initiation after failure of multiple oral medications, real world implementation of these guidelines remain challenging. With few exceptions, little is known about predictors of insulin initiation in practice.
Since patients and providers may view insulin as a treatment option of last resort, the purpose of this study is to examine in a cohort of veterans with poorly controlled T2DM.whether the strength of the established relationship between poor glucose control and the rate of insulin initiation could be altered by the number of oral glucose-lowering medication classes used by the patient prior to insulin initiation.
Section snippets
Setting and study sample
Steps taken to select the study cohort can be found in Fig. 1. We assembled the cohort using records in various VHA electronic databases between October 1, 1998 and May 31, 2006 (as described below). To identify patients with T2DM, we selected those who had at least one ICD-9-CM code 250.00 or 250.02 diagnosis recorded at either an inpatient or outpatient visit each year in both FY 1999 and FY 2000. Compared to other well-validated methods of identifying patients with diabetes studies using VHA
Results
As shown in Fig. 1, the cohort was drawn from 158,062 patients with T2DM, who participated in the VLHS in 1999. In this cohort, 69,613 (44%) had 2 A1c values ≥8% within a 12-month time frame, and 40,537 of those had not received a prescription for insulin prior to the elevated A1c value. This group comprised our study cohort.
In our study cohort of 40,537 Veterans with T2DM and a sustained elevation of A1c, 17,519 (43.2%) had insulin initiated and 23,003 never received insulin during the study
Discussion
In this national sample of veterans with poorly controlled T2DM, less than half of patients during the study period (from the date of the first A1c value ≥8.0% to the earliest between May 31, 2006 and the date of death) had insulin initiated. The average time lag between the first elevated A1c value (defined as the first A1c ≥8%) and first insulin prescription was approximately 4.6 years. Although the rate of insulin initiation increased as A1c increased, the strength of this relationship was
Limitations/challenges and recommendation
This study is limited by including only veterans who responded to the VLHS in 1999 [18]. This may have induced some selection bias toward those without a mental illness, those whose self-rated physical health was higher and those with more social support. Other limitations encountered in this study include the lack of any measure of patient adherence to medication, diet and exercise, all important factors in glucose control. Patients who are not adhering to oral medications are less likely to
Conflict of interest statement
The authors have no conflict of interest to declare.
Acknowledgements
This research was supported by the National Institutes of Health/National Institute for Diabetes, Digestive and Kidney Disorders (Grant # K25 DK075092 and Grant # R18 DK075692) and the Department of Veterans Affairs, Veterans Health Administration, Health Services Research and Development Service. The views expressed in this article are those of the authors and do not necessarily represent the views of the Department of Veterans Affairs.
References (29)
- et al.
Suboptimal control of glycemia, blood pressure and LDL cholesterol in overweight adults with diabetes: the Look AHEAD Study
J. Diabetes Complications
(2008) - et al.
Intensive insulin therapy prevents the progression of diabetic microvascular complications in Japanese patients with non-insulin dependent diabetes mellitus: a randomized prospective 6-year study
Diabetes Res. Clin. Pract.
(1995) - et al.
Addressing barriers to initiation of insulin in patients with type 2 diabetes
Prim. Care Diabetes
(2010) - et al.
Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases
J. Clin. Epidemiol.
(1992) - et al.
Improvement in diabetes processes of care and intermediate outcomes: United States 1988–2002
Ann. Intern. Med.
(2006) Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). UK Prospective Diabetes Study (UKPDS) Group
Lancet
(1998)- et al.
Clinical inertia in response to inadequate glycemic control
Diabetes Care
(2005) - et al.
Influence of elevated cardiometabolic risk factor levels on treatment changes in type 2 diabetes
Diabetes Care
(2008) - et al.
Clinical predictors of disease progression and medication initiation in untreated patients with type 2 diabetes and A1c less than 7
Diabetes Care
(2008) Early insulin: an important therapeutic strategy
Diabetes Care
(2005)
Resistance to insulin therapy among patients and providers: results of the cross-national diabetes attitudes, wishes, and needs (DAWN) study
Diabetes Care
Psychological insulin resistance: scope of the problem
Diabetes Educ.
Early insulin therapy for type 2 diabetes
Diabetes Care
The burden of treatment failure in type 2 diabetes
Diabetes Care
Cited by (12)
Influence of macro- and microvascular comorbidity on time to insulin initiation in type 2 diabetes patients: A retrospective database analysis in Germany, France, and UK
2013, Primary Care DiabetesCitation Excerpt :Those patients who had insulin initiated had higher prescription prevalence of oral antidiabetic agents (sulfonylureas, metformin, thiazolidinediones, acarbose) [8]. Insulin initiation was more common among patients who received several classes of oral antidiabetics, suggesting that additional oral agents are used before transition to insulin therapy [8]. DPP-4 inhibitors or GLP-1 analogs were not included because the study period was from 1998 to 2006 (before market launch) [8].
Precision Medicine in Diabetes
2023, Handbook of Experimental PharmacologyThe impact of phenotype, ethnicity and genotype on progression of type 2 diabetes mellitus
2020, Endocrinology, Diabetes and MetabolismDelay of insulin therapy in type 2 diabetics
2020, Tunisie MedicalePredictors of Insulin Initiation in Patients with Type 2 Diabetes: An Analysis of the Look AHEAD Randomized Trial
2018, Journal of General Internal Medicine