Trajectories of glycemic control with clinical pharmacy specialist management of veterans with type 2 diabetes

https://doi.org/10.1016/j.sapharm.2021.08.010Get rights and content

Abstract

Background

Improved control of glycemic control likely lowers the risk of diabetes complications and clinical pharmacy specialist (CPS) services can improve glycemic control. Though the pattern of control may also matter in terms of outcomes.

Objectives

The objective of this study was to examine the longitudinal trajectories of HbA1c among a large population of Veterans with type 2 diabetes who received CPS-led diabetes management.

Methods

This is an observational, multicenter cohort study of Veterans with type-2 diabetes managed by CPSs between 7/1/2013 and 7/1/2017 with baseline glycosylated hemoglobin (HbA1c) level ≥8%. Two years of HbA1c measurements were used to group patients into distinct patterns of HbA1c trajectories over time using group-based trajectory modeling. Characteristics associated with successful HbA1c trajectories and association of assigned trajectories with all-cause and diabetes-related hospitalizations were analyzed using logistic regression.

Results

A total of 4119 Veterans were included and able to be successfully segmented into six distinct HbA1c trajectory groups over time: High Gradually Decreasing (n = 325, 7.9%), Moderate Early Decline (n = 1692, 41.1%), Large Early Decline (n = 231, 5.6%), Uncontrolled Stable (n = 1468, 35.6%), Early Decline/Subsequent Increase (n = 266, 6.5%), and Very Uncontrolled Stable (n = 137, 3.3%). The distinguishing factor between successful and less successful trajectories appears to be the progress made within the first six months of pharmacist management.

Conclusions

Significant variability exists in the pattern of glycemic control over time of type 2 diabetes patients managed by clinical pharmacy specialists. Limited resources should be first prioritized to managing patients with very elevated HbA1c and into the first six months of CPS management.

Introduction

Diabetes is a chronic illness that continues to be a public health problem, particularly in the Department of Veterans Affairs (VA), with an estimated prevalence among veterans of 20.5% in 2013–2014.1 Nearly half of patients nationally have poorly-controlled diabetes.2 Numerous studies have documented the benefits of achieving improved glycemic control, particularly on the prevention of microvascular complications.4, 5, 6, 7, 8, 9 Consequently, the American Diabetes Association guidelines recommend targeting an HbA1c level of <7% for most individuals.10 Moreover, glycemic control in diabetes has become an important measure of healthcare quality in the Healthcare Effectiveness Data and Information Set (HEDIS), including in the VA system.3

However, achieving optimal health outcomes for patients with diabetes requires consistent glycemic control over time. Prior studies using group-based trajectory modeling demonstrate that longitudinal patterns of glycemic control vary widely in the diabetes population.11, 12, 13, 14, 15 The pattern of glycemic control over time have been associated with risk of mortality, microvascular complications, and cognitive dysfunction.11, 12, 13, 14, 15, 16, 17 For instance, both the analyses by Walraven et al. and Laiteerapong eta al. were able to distinguish distinct trajectory groups of glycemic control in patients with type 2 diabetes showing that the prevalence of microvascular complications was greater in those following trajectories compared to a trajectory that follows more consistent reasonably controlled HbA1c levels.12,13 A similar association was also found by Low et al. showing that as compared to a ‘near-optimal stable’ trajectory, those classified into a ‘moderate-increasing’ trajectory had a greater incidence of chronic kidney disease progression.15 While using a modeling method other than group-based trajectory modeling, a study by Gebregziabher et al. showed in a veteran population that a positive slope in change in HbA1c change over time was associated with increased mortality.14 Additionally, Luo et al., found an increase in mortality in patients classified into the ‘moderate-increase’ and ‘high-decrease’ trajectories as compared to a ‘low-stable’ trajectory.16 Finally, an analysis in elderly patients by Ravona-Springer et al. found that non-stable HbA1c trajectory groups were associated with worse cognitive performance than those classified into stable HbA1c trajectory groups.17 Analyses such as these provide evidence that in addition to achieving a certain HbA1c target at a set time point, that in terms of complications it may also matter how that glycemic control varies longitudinally over time.

Thus, effective strategies for improving diabetes-related outcomes must not only lower patients’ HbA1c to target levels but to also keep them stable long-term. One such strategy within the VA system is diabetes management by clinical pharmacy specialists (CPS) that are trained and credentialed, often with prescribing authority, for managing chronic medical conditions. Prior analyses have shown CPS-led management of diabetes can reduce HbA1c.18, 19, 20, 21, 22 A recent nationwide retrospective cohort study of effectiveness of VA CPSs in managing diabetes in 53 VA medical centers with over 12,000 patients and propensity-score matched controls showed that CPS providers managed diabetes as well as primary care providers.23

While CPS-led management of diabetes can likely assist with initial attainment of HbA1c goals, little is known about long-term patterns of glycemic control among patients who receive CPS-led diabetes management. This information is necessary to improve the delivery and outcomes of CPS-led diabetes care and to better target CPS services to patients most likely to benefit. The objective of this study was to examine the longitudinal trajectories of HbA1c, and associated predictors, among a large population of veterans with type 2 diabetes who received CPS-led diabetes managed services.

Section snippets

Study design and data

We conducted an observational, multi-site, retrospective cohort study of veterans with type 2 diabetes who have received CPS management within the Veterans Integrated Service Network (VISN) 15 “VA Heartland Network”, consisting of eight VA medical centers across Kansas, Missouri, and Illinois. Patient characteristics and healthcare service use records were identified using the VA national Corporate Data Warehouse (CDW) (VA 79 FR 4377) using resources and facilities at the VA Informatics and

Results

Our analytic cohort included 4119 veterans (see Fig. 1 for cohort selection algorithm). Most subjects were male (96.7%) and Caucasian (75.5%) with a mean age of 64.1 years (Table 1). The cohort overall had a mean baseline HbA1c of approximately 10% [86 mmol/mol], a mean BMI of 34 kg/m2, and were prescribed on average 2 hypoglycemic medications.

The final model contained six distinct trajectory groups of HbA1c over time (Fig. 2): High gradually decreasing, moderate early decline, large early

Discussion

Utilizing a large sample of over 4000 veterans from eight VA medical centers, this study provides the first known evaluation of the distinct trajectories of glycemic control after initiation of CPS-led management of type 2 diabetes. We found marked heterogeneity in trajectories of glycemic control after starting CPS-led diabetes management.

As reported, patients were successfully segmented into six distinct trajectories of HbA1c over time after initiation of CPS management (Fig. 2).

Conclusions

Significant variability exists in the pattern of glycemic control over time of type 2 diabetes patients managed by clinical pharmacy specialists as evidenced by the ability to divide patients in six distinct trajectories. Limited CPS provider supply should be prioritized to managing patients with very elevated initial HbA1c with particular intensity for the first 6 months. Further work on this topic should investigate interventions to help those patients following likely unsuccessful glycemic

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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