Better the Time in Range, Longer the Time in Life

Over three decades ago, a landmark clinical milestone irrevocably transformed diabetes care. The Diabetes Control and Complications Trial (DCCT) (1993) provided conclusive evidence that intensive glycemic control, reflected by lower HbA1c levels, substantially reduces the risk of microvascular complications, with later evidence suggesting long-term cardiovascular benefit in individuals with diabetes.[1-3] Similarly, in 1998, the UK Prospective Diabetes Study (UKPDS) showed that intensive glycemic control alongside blood pressure management markedly reduces diabetes-related microvascular complications. The reduced mortality observed among UKPDS participants receiving intensive treatment, compared with those receiving conventional therapy for type 2 diabetes, may therefore be attributed to these comprehensive improvements in clinical care.[4,5] These seminal findings established the central paradigm of tight glycemic control and continued to underpin global diabetes management frameworks. However, this pursuit of optimal HbA1c targets was accompanied by a sobering paradox, an increased burden of hypoglycemia. Subsequent large-scale studies reinforced this concern. In the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial, intensive glycemic control was associated with a significant rise in all-cause mortality, driven largely by a 35% increase in cardiovascular deaths compared with standard therapy, prompting early termination of the trial.[6] The underlying mechanisms remain incompletely understood and are likely multifactorial, with severe hypoglycemia (SH), rapid reduction in HbA1c, and patient-specific risk profiles all considered potential contributors rather than a single definitive cause. Such evidence reinforced the clinical reality that individuals, particularly those treated with insulin or insulin secretagogues, often faced severe or even life-threatening hypoglycemic episodes in their effort to achieve these targets.[7] Furthermore, impaired awareness of hypoglycemia (IAH), characterized by reduced recognition of hypoglycemic symptoms, increases the likelihood of SH, a potentially life-threatening complication that compromises the attainment of glycemic targets.[8] Together, these findings underscored the need for a more nuanced approach to glycemic management, one that balances efficacy with safety. Building on these lessons, recent technological advancements, particularly continuous glucose monitoring (CGM), have transformed the pursuit of glycemic control from a retrospective process into a real-time, precision-guided endeavor. In the era of CGM, particularly with the advent of real-time CGM, diabetes management has entered a new frontier, one that enables precise, data-driven glycemic control while substantially reducing the risk of hypoglycemia. Unlike HbA1c, which represents an average measure and conceals daily fluctuations, CGM provides a dynamic and continuous depiction of glycemic variability,[9] with the principal objective of increasing time in range (TIR) while reducing time below range (TBR). Reducing TBR is of considerable clinical importance, as studies have demonstrated that higher TBR is associated with a blunted epinephrine response during hypoglycemic clamp testing, indicative of impaired counterregulation. Such attenuation of the epinephrine response may weaken the body’s ability to defend against subsequent hypoglycemic episodes. In addition, increased TBR has been positively correlated with IAH and a heightened risk of SH.[8] Chronic hyperglycemia contributes to cognitive decline and memory impairment, whereas SH may trigger cardiac arrhythmias, stroke, or sudden death.[6,10,11] This shift from an HbA1c-centric approach to one emphasizing TIR represents a major paradigm change in diabetes care, highlighting that the pursuit of better TIR is intrinsically linked to longer time in life. While individuals who achieve improved HbA1c often live longer, those with frequent hypoglycemic episodes face a higher risk of dementia, altered cognition, and psychological distress.[12] While direct causal evidence linking TIR to reduced mortality is still evolving, TIR provides a clinically intuitive and actionable metric that reflects day-to-day glucose control more accurately than HbA1c alone. In this context, the principle that better TIR may translate into longer and healthier life reflects both current evidence and future promise. Beyond its technological sophistication, CGM serves as a transformative tool that fosters behavioral adaptation, self-awareness, and patient empowerment. True empowerment, however, begins with the healthcare provider. Clinicians who have not directly engaged with CGM may find it difficult to fully appreciate its practical implications or effectively communicate its potential to patients. It is therefore recommended that healthcare professionals periodically experience CGM use themselves, enabling a deeper understanding of how daily factors such as diet, physical activity, sleep, stress, and travel affect glucose dynamics. Such an informed experiential perspective enhances empathy, improves the quality of patient counseling, and reinforces the clinician–patient partnership at the core of modern diabetes care. The clinical utility of CGM now spans the full spectrum of diabetes care.[13] Beyond type 1 diabetes or intensive insulin regimens, CGM benefits individuals with type 2 diabetes on oral agents, basal or premix insulin, and even combination therapies with GLP-1 receptor agonists. Emerging applications of CGM in individuals with prediabetes and metabolic risk conditions are being explored,[14] particularly to enhance lifestyle awareness and facilitate early behavioral modification, although routine use in these populations is not yet supported by robust guideline-based evidence. Personalized glycemic targets are fundamental to modern diabetes management.[15] Optimal TIR should be individualized, taking into account patient age, comorbidities, and susceptibility to hypoglycemia. In older adults or those with established complications such as neuropathy or nephropathy, rigid adherence to stringent TIR targets may result in greater harm than benefit. Accordingly, CGM-guided therapy must strike a careful balance between safety and efficacy, tailoring treatment goals to each patient’s physiological profile, clinical context, and personal preferences. While personalized targets guide safe and effective glycemic management at the individual level, translating these strategies into routine clinical practice, particularly in resource-constrained settings such as India, presents practical challenges that must be addressed to fully realize the benefits of CGM. In India, the seamless integration of CGM into routine clinical practice remains influenced by a constellation of systemic and pragmatic barriers, including short consultation durations, limited reimbursement frameworks, variable device affordability, and persisting concerns regarding measurement accuracy. While routine clinical consultations are often short, the effective use of CGM necessitates more extensive, high-quality interactions, as clinicians must dedicate additional time to educate patients on the meaningful, long-term implications of CGM for glycemic control and quality of life. Economic considerations, including consultation fees and out-of-pocket device costs, further influence uptake. Despite these challenges, the long-term clinical and psychosocial benefits, including reduced hospitalizations, lower incidence of acute complications, improved adherence to therapy, and enhanced patient quality of life, substantially outweigh the initial barriers. As CGM technology becomes increasingly accessible and integrated into routine care, it holds considerable promise for transforming diabetes management into a more proactive, individualized, and participatory model, optimizing both clinical outcomes and patient empowerment. The transition from static, retrospective measures such as HbA1c to dynamic, real-time metrics like TIR represents a pivotal evolution in the paradigm of diabetes management. CGM exemplifies the integration of technological innovation, individualized care, and patient empowerment, enabling more precise, informed, and proactive management. By prioritizing TIR, clinicians and patients alike can not only optimize glycemic control but also meaningfully enhance the quality and longevity of life. Indeed, the overarching principle is clear; the better the TIR, the longer and more fulfilling the time in life, underscoring the profound clinical and psychosocial impact of CGM-guided diabetes care. TIR is both a goal and a promise: better management today translates into longer, richer, and more empowered lives tomorrow, exemplifying the transformative impact of CGM. This is an opportune time for the routine adoption of CGM. Advances in sensor technology have produced devices that are more accurate, user-friendly, and adaptable to individual preferences and clinical needs. Contemporary CGM systems now achieve mean absolute relative difference (MARD) values approaching or below 10%, highlighting accuracy comparable to, and in some contexts surpassing, traditional glucose monitoring approaches,[16] thereby reiterating the principle that better TIR may ultimately translate into longer and healthier life. In this issue, two complementary contributions further underscore the expanding role of CGM across diverse clinical contexts. The study Optimizing the Use of CGM in People with Type 2 Diabetes on Noninsulin-based Regimens: A Case Series with Narrative Review and Expert Opinion highlights CGM as a valuable adjunct to HbA1c in individuals with type 2 diabetes on noninsulin therapy, providing a more comprehensive understanding of daily glycemic patterns, cardiovascular risk, and lifestyle-guided self-management through ambulatory glucose profile insights. In parallel, Intermittent Use of Flash Glucose Monitoring as a Useful Tool for Patients with Type 1 Diabetes in Developing Countries demonstrates that even intermittent flash glucose monitoring can serve as a practical and cost-effective strategy, improving glycemic control and reducing acute complications compared with SMBG alone. Together, these findings reinforce the central message of this editorial that advancing access to CGM, whether continuous or intermittent, can enable better TIR, which may longer time in life.