Trajectories of glycemic control with clinical pharmacy specialist management of veterans with type 2 diabetes
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.
References (29)
- et al.
Ten-year hemoglobin A1c trajectories and outcomes in type 2 diabetes mellitus: the diabetes & aging study
J Diabet Complicat
(2017) - et al.
Longitudinal trends in HbA1c and associations with comorbidity and all-cause mortality in Asian patients with type 2 diabetes: a cohort study
Diabetes Res Clin Pract
(2017) - et al.
Prevalence of and trends in diabetes among veterans, United States, 2005–2014
Prev Chronic Dis
(2017) - et al.
Achievement of glycated hemoglobin goals in the US remains unchanged through 2014
Diabetes Ther
(2017) The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus
N Engl J Med
(1993)Sustained effect of intensive treatment of type 1 diabetes mellitus on development and progression of diabetic nephropathy
J Am Med Assoc
(2003)- et al.
Neuropathy and related findings in the diabetes control and complications trial/epidemiology of diabetes interventions and complications study
Diabetes Care
(2014) Intensive blood-glucose control with sulfonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33)
Lancet
(1998)Effect of intensive blood-glucose control with metformin on complications in overweight patients with type 2 diabetes (UKPDS 34)
Lancet
(1998)