Prediabetes Doesn't Wait for Symptoms: Why Opportunistic Screening Should Become Routine? - Prof(Dr). Aravinda Jagadeesha

Prediabetes-An Accelerating Metabolic Epidemic

Prediabetes represents a critical intermediate stage of dysglycemia characterized by blood glucose levels elevated beyond normal ranges yet remaining below the diagnostic threshold for diabetes mellitus (1). Globally, the burden of prediabetes has reached alarming proportions, with an estimated 634.8 million adults representing 12.0% of the global adult population having impaired glucose tolerance in 2024 (2). Projections indicate that by 2050, cases will surge to 846.5 million, highlighting an accelerating epidemic that places immense strain on health systems and contributes to the growing global burden of non-communicable diseases (3). In India, prediabetes imposes a substantial burden, affecting 136 million individuals; 15.3% of the population aged 20 years and above (3).

What is the Estimated Rate of Conversion of Prediabetes in India?

The younger age of onset and faster progression from prediabetes to diabetes among Indians further increases the disease burden (3). Indians spend an average of 35 to 40 years in normoglycemia before dysglycemia begins. The rate of conversion from normal glucose tolerance (NGT) to IFG (impaired fasting glucose) is 7.5% per year. Among those with IFG, 22.8% revert to NGT, while 8.6% progress to diabetes annually (4)

Prediabetes, Associated Comorbidities & Complications Risks – Are We Overlooking Them?

Prediabetes is commonly associated with multiple comorbidities that contribute to the overall disease burden. In addition to increasing the risk of progression to type 2 diabetes, it is associated with complications such as cardiovascular disease, dyslipidemia, chronic kidney disease, and unfavorable microvascular sequels; along with co-morbid associations like atrial fibrillation, abdominal obesity, MASLD, erectile dysfunction and reproductive issues, polycystic ovary syndrome (now, PMOS), mental health disorders and loneliness. Evidence also suggests an increased cancer and mortality risk associated with prediabetes (5).

Figure 1. Comorbid associations and complication risks associated with prediabetes.

Why Opportunistic Screening Matters? Revisiting Supporting Evidence

According to the ADA Standards of Care 2026, prediabetes is diagnosed by any one of the following: fasting plasma glucose (FPG) 100–125 mg/dL, 2-hour plasma glucose (2-h PG) 140–199 mg/dL during a 75-g oral glucose tolerance test (OGTT), or HbA1c 5.7–6.4%. (6) The International Diabetes Federation (IDF) recently recommended a 1-hour plasma glucose (1-h PG) threshold of ≥155 mg/dL (8.6 mmol/L) during a 75-g oral glucose tolerance test (OGTT) to identify intermediate hyperglycaemia (prediabetes) (7).

· A study evaluating opportunistic screening in an ophthalmic outpatient department (OPD) found that among 75 apparently healthy adults aged 25–45 years visiting the eye hospital for refractive error management or accompanying family members, 41 individuals (54.66%) were identified as having prediabetes using HbA1c testing. The findings suggest that ophthalmic OPDs may offer an opportunity for prediabetes screening, although larger studies are needed to substantiate this approach (8).

· A narrative review highlighted that dental practices provide an effective setting for opportunistic prediabetes screening. More than 90% of patients with periodontal disease meet the ADA criteria for diabetes screening, while a meta-analysis cited in the review reported that 40.1% of patients who visited dental care settings and were screened using chairside HbA1c had elevated glycaemic values and 47.38% of screen-positive individuals were confirmed to have prediabetes. These findings support integrating chairside HbA1c testing and referral pathways into routine dental practice (9).

· Once identified, lifestyle-induced weight loss of >5% led to remission of prediabetes in 43% of participants, with a 73% relative risk reduction in the risk of developing type 2 diabetes (10).

Prediabetes Screening Guidelines: Who Should Be Tested and When?

Given that prediabetes is frequently asymptomatic, the RSSDI 2024 guidelines recommend opportunistic screening to improve early detection. The guidelines identify routine healthcare encounters—including visits for unrelated illnesses, antenatal and dental care, family members of people with diabetes, and overweight children and adolescents- as important opportunities to identify individuals at risk (11)

Proactive Intervention in Prediabetes – A Stitch in Time Saves Nine

Prediabetes, however, should not be considered a path to diabetes; rather, it should be a window of opportunity for the prevention of diabetes. The early screening, detection, and early treatment of prediabetes should be made a national priority (13). Among pharmacological therapies, metformin has the most robust efficacy and safety data for diabetes prevention in people with prediabetes (6).

Metformin- Quick Take in Prediabetes

· Metformin is recommended by the ADA Standards of Care 2026 for selected adults with prediabetes who are at high risk of progression to type 2 diabetes. (6)

· This recommendation is supported by evidence from the Diabetes Prevention Program (DPP) and its long-term follow-up (DPPOS), which demonstrated that metformin reduces the relative risk of progression to type 2 diabetes, with sustained benefits observed over long-term follow-up (6).

Expert Perspective

Prediabetes is a clinically actionable stage in the natural history of dysglycaemia. Early identification through opportunistic screening allows clinicians to implement structured lifestyle interventions and, where appropriate, evidence-based pharmacotherapy such as metformin in high-risk individuals, thereby reducing the likelihood of progression to type 2 diabetes and its associated complications.

Practice Takeaways

· Screen opportunistically: Integrate guideline-based prediabetes screening into every appropriate clinical encounter to detect dysglycaemia before symptoms develop.

· Intervene early: Initiate structured lifestyle intervention promptly and address associated cardiometabolic risk factors to prevent disease progression.

· Personalize prevention: Consider metformin in adults with prediabetes, when indicated alongside regular monitoring and follow-up.

Abbreviations: ADA: American Diabetes Association, DPP: Diabetes Prevention Program, DPPOS: Diabetes Prevention Program Outcomes Study, FPG: fasting plasma glucose, HbA1c: glycated haemoglobin, IDF: International Diabetes Federation, IFG: impaired fasting glucose, MASLD: metabolic dysfunction-associated steatotic liver disease, NAFLD: non-alcoholic fatty liver disease, NGT: normal glucose tolerance, OGTT: oral glucose tolerance test, OPD: outpatient department, PCOS: polycystic ovary syndrome, PG: plasma glucose, RSSDI: Research Society for the Study of Diabetes in India, T2DM: type 2 diabetes mellitus.