Early Treatment during Prediabetes Improves Clinical Outcomes and Lowers Healthcare Costs

29 Dec, 16

Introduction

In many countries, the burden of prediabetes is greater than that of diabetes. Moreover, 15-30% of individuals with prediabetes progress to type-2 diabetes mellitus (T2DM) within 5 years, and are hence exposed to a higher risk of various complications such as stroke, myocardial infarction and microvascular complications. In addition to this, diabetes also leads to a heavy economic burden, both for the country and the individual. Globally, USD 673 billion is the healthcare expenditure due to diabetes. Nevertheless, the available clinical data is too scarce to evaluate the clinical and economic impact of early treatment, specifically with oral antidiabetic (OAD) agents, in individuals with prediabetes.

Aims

To determine the impact of OAD pretreatment on clinical outcomes and health resource utilization among commercially insured T2DM patients in the United States.
To compare the time from T2DM diagnosis to insulin initiation in individuals who did and did not receive OAD pretreatment.

Patient Profile

Pretreatment Patients

Commercially insured and newly diagnosed T2DM patients (age ≥18 years) with OAD use at least 3 months before the index date (when the diagnosis of T2DM was established) (n= 241856)

Patients without Pretreatment

Commercially insured and newly diagnosed T2DM patients (age ≥18 years) without OAD use ≥3 months prior to the index date or pre-index use of insulin (n=624749)
None of the study subjects had glycosylated hemoglobin (HbA1c) >6.4% prior to 90 days of the index date.

Methods

Study Design

Retrospective cohort study

Treatment Strategy

Various types of OAD used included:

Sulfonylureas
Biguanides
Thiazolidinediones
Dipeptidyl-peptidase-4 (DPP-4) inhibitors
Others

Outcomes

Post-index date healthcare resource utilization and costs, as per the pretreatment status
Utilization (proportion with use and number of visits) and costs associated with inpatient stays, emergency department (ED) visits, physician office visits and outpatient pharmacy claims
A separate analysis of total and diabetes-related utilization and costs
Time to insulin initiation

Results

Mean follow-up for pretreatment patients was 2.9 years and that for patients without pretreatment was 3.1 years
Of the entire study population (n=866,605), 27.9% (n=241,856) patients received pretreatment prior to T2DM diagnosis
The incidence of monthly diabetes-related hospitalization and the incidence of total monthly hospitalization was slightly lower in the patients receiving pretreatment vs. those without pretreatment (Table 1)
Pretreated patients also had less number of ED visits and physician office visits. However, they had higher pharmacy prescriptions per month (total and diabetes-related) when compared with patients without pretreatment (Table 1)

Table 1: The Healthcare utilization in the study groups

Healthcare Utilization	Pretreatment Group	No-Pretreatment Group	P value
Hospitalizations per Month
Diabetes-related	0.009	0.011	<0.0001
Total	0.016	0.017	<0.0001
ED Visits per Month
Diabetes-related	0.016	0.018	<0.0001
Total	0.042	0.046	<0.0001
Physician Office Visits per Month
Diabetes-related	0.18	0.22	<0.0001
Total	0.58	0.62	<0.0001
Pharmacy Prescriptions per Month
Diabetes-related	0.65	0.49	<0.0001
Total	3.16	2.71	<0.0001

As per the expectations, patients who received pretreatment incurred significantly higher monthly diabetes-related pharmacy costs as well as overall monthly pharmacy costs as compared to those who did not receive pretreatment (Table 2)
Nevertheless, patients receiving pretreatment had lower mean monthly total costs and diabetes-related costs as compared to those who were not pretreated (Table 2)

Table 2: Health care costs per month in the study groups

Healthcare Cost per month	Pretreatment Group	No-pretreatment group	*Adjusted Mean Difference**	P value
Hospitalizations
Diabetes-related	$123	$153	$89	<0.0001
Total	$313	$404	$91	<0.0001
Emergency Department Visits
Diabetes-related	$9	$12	$3	<0.0001
Total	$26	$32	$6	<0.0001
Pharmacy Costs per Month
Diabetes-related	$66	$36	-$24	<0.0001
Total	$255	$198	-$144	<0.0001
Total Healthcare Costs per Month
Diabetes-related	$207	$214	-$60	0.0012
Total	$625	$671	$354	<0.0001

_{*adjusted for age, gender, region, health plan type, index year and baseline HbA1c}

Pretreatment with OAD was associated with a lower insulin initiation probability at 1.7 years. At 2 years the cumulative probability for insulin initiation was 8.9% in pretreated patients vs. 11% in patients not pretreated with OAD. However, the probability for insulin initiation was similar in both the study groups after 2 years (hazard ratio [HR]; 0.96).

Conclusions

Pretreatment with OADs modestly delayed the initiation of insulin therapy and lowered the total healthcare costs (healthcare resource utilization and costs for hospitalizations, physician office visits, and ED use)
Slightly higher pharmacy costs in the pretreated patients were suggestive of intense overall pharmacologic management in the pretreated group. These findings however require a further validation through appropriate studies to better understand the clinical benefits of T2DM pretreatment in broader context for overall patient disease management
Even modest reductions in cost can lead to large overall savings in the long-run

Diabetes Res Clin Pract. 2016; 122: 162-69