Analysis of the patient population of this study revealed that one of ten older adults with T2DM were overtreated for glycemia. When the number of insufficiently treated individuals were included in the analysis, one in four older adults with T2DM undergoing a routine control evaluation required modification of their antihyperglycemic treatment. Almost a similar proportion required modification of their antihypertensive treatment, but overtreatment of BP was overall less common. Our findings also show that participating physicians deintensified treatment in only 25% of patients overtreated for glycemia and in only 10.9% of patients overtreated for BP. In comparison, physicians intensified diabetes treatment in the majority of those with uncontrolled glycemia but did not modify the antihypertensive treatment in the > 90% of patients with uncontrolled BP.
Both the ADA and AGS recommend more liberal HbA1c goals for older patients, particularly in those with functional limitations [10, 15] as functional decline may be considered as one of the major complications of diabetes mellitus over the long term. In a sample of patients from the Atherosclerosis Risk in Communities Study, diabetes mellitus was associated with functional disability in older adults that could not be explained by known risk factors and comorbidities, including poor glycemic control and medication use . Thus, these patients may benefit from regular assessment of functionality even though the level of evidence to support this recommendation is low .
Studies published to date have shown a variable frequency of overtreatment of diabetes mellitus among older adults. A recent analysis of data extracted from a large US Medicare claims database revealed that 10.8% of patients aged ≥ 65 years were potentially overtreated . Overtreatment in that study was defined as HbA1c < 6.5% plus the use of any antihyperglycemic drug in addition to metformin. In the current survey, we selected a more stringent criterion for diabetes overtreatment (HbA1c < 6.5% plus the use of ≥ 2 oral antihyperglycemic drugs or any insulin) but found that the proportion of overtreated individuals was similar to that in the US sample. However, it is likely that both studies underestimated the number of overtreated patients because HbA1c goals are currently not less than 7% for all older adults, and higher thresholds are defined for individuals with multimorbidity and/or functional dependence [10, 13]. Nevertheless, in the absence of evidence from randomized controlled trials (RCTs), there is no agreement on the definition of overtreatment, intensive treatment, or excessive treatment , and these terms have been used interchangeably.
Low adherence to treatment is a known challenge in diabetes management [25,26,27]. However, overemphasizing metabolic control may cause excessive treatment of persons with T2DM of all ages. In the present study, overtreated patients had better sociodemographic characteristics and more favorable care indicators than those who were optimally treated or undertreated. In addition, overtreated patients more often chose for follow-up in a private clinic and were more often on oral antihyperglycemics than injectable drugs. These findings suggest that medical treatment unexpectedly went too far regarding the management of the overtreated patients in our sample. In a US sample of patients with T2DM, Maciejewski et al. reported that individuals enrolled in a Medicaid program were potentially overtreated compared to those not enrolled in a Medicaid program , suggesting that consistent provision of diabetes care improves health-related outcomes. Since all of our participants were covered by the state health insurance, we were not able to examine the interaction between the health insurance program and overtreatment. However, follow-up at a private clinic was a predictor of overtreatment of T2DM in our study. Although what makes a patient choose a private setting can be multifactorial , a private clinic may offer more personal care within sufficient time and may provide a more convenient environment compared to public facilities. Also, a private clinic setting can improve physician–patient agreement, which is a predictor of medication compliance in the primary care setting . Moreover, favorable health beliefs and provision of better illness-related support are positively associated with adherence to health-promoting activities consisting of a diabetic regimen and metabolic control [30, 31]. In a RCT, Munshi and colleagues showed that the assessment and resolution of barriers to self-care improved glycemia and quality of care among older adults over a period of 12 months . Nevertheless, the results of our study suggest that sustained glycemic control through management at private clinics may unnecessarily result in excessive HbA1c reductions over time. Increasing the awareness of overtreatment among both physicians and patients may balance personal expectations and evidence-based care requirements in the management of T2DM.
In the present study, overtreatment of patients with diabetes mellitus was independently associated with the use of secretagogues, but treatment with insulin did not show any association with overtreatment. In two large studies from the USA, overtreated patients with diabetes mellitus were more frequently on insulin and sulfonylureas , and the proportion of the users of both drugs did not decrease in advanced age groups . Sulfonylureas are the second most prescribed antihyperglycemics across Europe , but they are also potent antihyperglycemics and associated with a well-known risk of hypoglycemia . Our findings suggest that sulfonylureas may cause excessive HbA1c reductions over time in older adults with T2DM; however, they are certainly agents that are less associated with the risk of hypoglycemia and even reduce the risk of cardiovascular events. Thus, when the glycemia is near normal and there are no apparent symptoms, cessation of treatment with an otherwise beneficial drug may also be arguable. It should be noted that in our study the use of such agents (e.g., SGLT-2 inhibitors, glucagon-like peptide 1 analogues) were not more common in the overtreatment group than in the other two groups.
Management of hypertension has long been complicated by concerns related to the excessive treatment of high BP . A cornerstone finding in this regard was the report of a relation of lower DBP to increased risk of major cardiovascular events in the general population, which was more pronounced in the presence of diabetes mellitus . Currently, based on evidence from RCTs , SBP < 120 mmHg is not recommended in patients with T2DM, including older adults. However, many patients still remain below the recommended BP range, and the picture gets worse in patients of advanced age. Various cohort studies have shown that age-adjusted prevalence of hypertension has remained stable in older people since late 1990s but that there has been a downtrend of mean SBP and DBP values and an improvement in BP control rates [39,40,41]. However, the numbers of patients aged > 80 years with seriously low BP, users of ≥ 3 antihypertensives , and frail elderly individuals receiving excessive antihypertensive treatment have also significantly increased [39,40,41]. The proportion of patients with T2DM overtreated for BP was relatively lower in the present study compared to previous studies, possibly be due to the selection of at least two antihypertensives as a criterion of hypertension. Interestingly, whereas the participants with overtreatment for glycemia were in a healthier condition, participants with overtreatment for BP had a worse disease status, suggesting that any relation between a lower BP and improved diabetes management was unlikely. Moreover, there was only a single independent predictor of BP overtreatment which was the use of an insulin-based treatment. Even though triple combinations of antihypertensive drugs may not increase the risk of adverse events compared to dual combinations in the general population, adverse events, such as dizziness, peripheral edema, and headache, are more common among the former , which may be more troublesome in an older adult with T2DM.
In the presence of unnecessarily low HbA1c values, physicians in our study deintensified antihyperglycemic treatment in only a small percentage of patients. Not surprisingly, reports from other health systems are not much different, and around two-thirds of overtreated individuals continue with their current antihyperglycemic regimen [22, 40]. In previous survery, the numbers are also similar regarding the withdrawal or dose reduction of antihypertensives in subjects with excessively low BP [22, 40, 43]. In our study, physician reaction to uncontrolled glycemia differed greatly from that to uncontrolled BP. While glucose-lowering therapy was intensified in most patients with uncontrolled glycemia, < 10% of those with uncontrolled BP had their treatment modified. The decision to withdraw a medication is influenced by multiple barriers and enablers from both the patients and physicians. Skepticism on the appropriateness of withdrawing, absence of a process for cessation, and dislike of medications are the potential barriers and enablers of the patients . On the physician side, problem awareness, inertia secondary to lower perceived value for stopping or continuing, self-efficacy or ability to alter prescribing, and feasibility of altering prescribing in routine care environments were identified as barriers or enablers . In addition, system-level barriers (e.g., policy, finance) and environmental factors  may also delay the time of deprescribing. However, with the available data from ourstudy, we are unable to comment on the actual causes of physicians’ inertia to modify antihypertensive and antiglycemic medications. In order to effectively facilitate deprescribing in clinical practice, future studies are needed to better identify barriers and enablers specific to patients with diabetes mellitus and their physicians.
Our study has a number of limitations. First, since the TEMD study was conducted in a population aged ≥ 18 years, some variables that are more specific to older adults were not available, such as fall assessment, cognitive functions, functional status, and symptoms of depression. Second, the study sites were tertiary care centers, which makes it challenging to translate the findings to general services. Third, as there is no consensus on the definitions for diabetes overtreatment and hypertension overtreatment, we applied a modified set of criteria from existing studies. Therefore, the number of affected individuals may be different from those in other studies. Moreover, we do not have any data showing that patients had suffered from the harmful effects of overtreatment. Finally, we were not able to identify potential factors to influence deintensification or intensification of medications.