Discussion
In an effort to promote high-quality, evidence-based, and safe diabetes management at the individual and population levels, we proposed and evaluated a new quality indicator for the appropriateness of glucose-lowering therapy among patients with type 2 diabetes. The ADTI balances the benefits of glucose-lowering therapy with the potential harms of hypoglycemia and treatment burden (eg, polypharmacy). When we applied the ADTI to a real-world population of 206 279 adults with type 2 diabetes, we found that 21.1% are potentially undertreated and 7.4% are potentially overtreated. As may be expected, overtreatment was far more common among clinically complex patients, while undertreatment was more common among patients with low complexity. These findings underscore the need for balanced quality indicators that can identify both excessive and inadequate treatment regimens. Using this information, clinicians can engage patients in conversation about their glucose-lowering therapy with the ultimate goal of aligning treatment regimens with patients’ clinical contexts as well as goals and preferences for care.
In the era of population health management, patients are often identified for surveillance or intervention only when they meet a particular metric (eg, high HbA1c) or experience an adverse health outcome (eg, hospitalization). The ADTI can help clinicians identify patients who may be either undertreated (the focus of currently existing quality measures, although in a less nuanced way) or overtreated (which has not been done to date). This approach also addresses other concerns raised about quality measurement,20 whether used for pay-for-performance/public reporting or to facilitate better care through quality improvement. ADTI is not a one-size-fits-all metric; instead, it promotes shared decision-making and personalization of glucose-lowering therapy. By inherently risk adjusting the recommended HbA1c level and the intensity of the glucose-lowering treatment regimen, ADTI encourages therapy that is more likely to be aligned with patient’s clinical context. It also recognizes the effort patients and clinicians make to control hyperglycemia even when HbA1c does not fall below 8%, while reinforcing the benefits of tighter glycemic control for less complex patients. Indeed, 31% of patients with HbA1c ≥8.0% would still be considered appropriately treated by the ADTI, either because of their underlying clinical complexity (wherein more intensive treatment may not be evidence based) or the complexity of their current treatment regimen (wherein more intensive treatment may be unsafe). Conversely, 7.2% of patients with HbA1c <8.0% were still classified as undertreated, reinforcing the benefits of more intensive glycemic control for otherwise healthy patients with long life expectancy. Finally, ADTI identified the 9.6% of patients with HbA1c ≥8.0% who were still overtreated and may benefit from treatment deintensification. By considering the number and type of glucose-lowering medications used to lower HbA1c, the ADTI may provide actionable guidance to patients and providers, and thereby overcome the therapeutic inertia of either overtreatment or undertreatment.
We found that clinically complex patients were 5.6 times more likely to be overtreated (rather than appropriately treated) than patients with low clinical complexity. High rates of potential overtreatment have been observed in a variety of settings and populations,9 21–27 and overtreated patients’ treatment regimens are rarely deintensified.23 24 28 While diabetes overtreatment measures have been proposed previously,11 29 30 they have not been widely incorporated into practice. This may be driven, in part, by clinician, health system, and patient-driven concerns about treatment deintensification.31 32 However, there is increasing recognition of the morbidity33–39 and mortality33 35–37 39–42 incurred by hypoglycemia, with concerted efforts by professional societies and regulatory bodies seeking to reduce these events. Proactive identification of at-risk overtreated patients would be the necessary first step.
Conversely, patients with low clinical complexity were 35% more likely to be undertreated than patients with high complexity. This is consistent with prior studies demonstrating high rates of poor glycemic control among younger patients with diabetes.9 43 44 Even though our study population comprised commercially insured individuals, younger patients may be more likely to be underinsured or have high deductible health plans, contributing to lower use of glucose-lowering medications,45 worse glycemic control, and poor health outcomes.46 The important role of cost and affordability of diabetes management is underscored by the inverse relationship between annual household income and odds of undertreatment, with higher income individuals significantly less likely to be undertreated. Medicare Advantage beneficiaries were also significantly less likely to be undertreated. This may reflect better access to care by retired Medicare Advantage beneficiaries as compared with working-age commercially insured patients, as well as the greater reliance on hypoglycemia-prone drugs (and lower rates of use of newer, non-hypoglycemia-prone drugs)19 47 that make it less likely for a patient to be classified as undertreated. Such undertreatment of patients who are likely to derive benefit from glycemic control reinforces the importance of continued focus on improving access to diabetes care and affordability of glucose-lowering therapies.
Black and Hispanic patients were significantly more likely to be undertreated than White patients. These disparities in diabetes management may be driven by the clinician’s failure to intensify therapy, the patient’s inability to access or afford recommended treatments, and greater burden of social determinants of health. Racial/ethnic minorities have worse diabetes-related health outcomes and greater risk of mortality compared with White patients,48 49 which may stem from gaps in care quality revealed by application of the ADTI.
Overtreatment and undertreatment, as identified by the ADTI, strongly correlated with subsequent risks of experiencing hypoglycemia and hyperglycemia requiring ED or hospital-level care. The rates of ED/hospital visits for hypoglycemia were 22.0 per 1000 people/year among the overtreated compared with 6.2 per 1000 people/year among those appropriately treated. This is important, particularly considering that the vast majority of severe hypoglycemic events do not culminate in an ED/hospital visit.50–52 Conversely, the rates of ED/hospital visits for hyperglycemia were 8.4 per 1000 people/year among the undertreated compared with 1.9 per 1000 people/year among those appropriately treated. Our findings suggest the potential preventability of these events with appropriate glucose management, particularly for the most vulnerable populations.
Our study has several important limitations. HbA1c is a surrogate measure of glycemic control and does not capture the totality of the diabetes care experience.53 While measures such as time in target range more accurately reflect real-time glycemia,54 this approach remains impractical for population-level performance measurement particularly for patients with type 2 diabetes, most of whom do not use (and do not need to use, depending on their treatment regimen) continuous glucose-monitoring technologies. The examined comorbidities do not reflect the full range of biological, sociological, economic, environmental, and behavioral factors that affect a patient’s complexity, contribute to burden of treatment and disease, and impact capacity of self-management and care. While we focused specifically on comorbid conditions identified by the clinical guidelines2 5 6 13 and associated with increased risk for hypoglycemia,1 other potentially pertinent comorbidities and non-clinical risk factors were not captured. We did not account for patient adherence to treatment or for their personal preferences of goals for care. Nevertheless, the ADTI can identify potentially inappropriate care in order to stimulate more nuanced and evidence-based clinical discussions about the goals and processes of diabetes care.
Finally, while the ADTI was evaluated among patients with private insurance and the evaluation results are likely to differ in other populations that may have greater barriers to care and affordability of brand name non-hypoglycemia-prone medications, the underlying principle of appropriate therapy is pertinent to all people with diabetes.
The goal of the ADTI is to ensure that all adults with diabetes receive high-quality, evidence-based, timely, and equitable care. It does so by taking into consideration the HbA1c level and each patient’s clinical complexity and treatment burden. This approach can be readily implemented across a range of clinical settings and healthcare delivery systems, as the required components are already used for quality measurement and reporting, including administrative data (diagnoses), HbA1c results, and patient age. Prospective evaluation of the impact of this indicator on diabetes care quality, patient health outcomes, and administrative burden, as compared with existing dichotomous measures, is necessary prior to its broad dissemination.