Diabetes clues your sugar test may miss

A simple glucose test is no longer the be-all and end-all of diabetes diagnosis. As it moves beyond types 1 and 2, with researchers discovering newer phenotypes and their unique challenges, diabetologists now argue that a glucose-centric paradigm fails to capture the full spectrum of the chronic condition, often detecting it a little late in the day. The future of early diabetes diagnosis rests on a comprehensive metabolic health assessment, rather than isolated glucose values, points out Dr Rajiv Kovil, head of diabetology at Zandra Healthcare, Mumbai. “Solely relying on fasting glucose, postprandial sugars, or the glycated haemoglobin (HbA1c) test trivialises diabetes, detecting it only after significant metabolic damage has already occurred,” he says. Fatty liver disease often precedes diabetes and is now recognised as a hepatic manifestation of insulin resistance. Fatty liver imaging, blood-based tests such as validated fibrosis (to detect liver scarring) and steatosis scores (that quantify liver fat) can be important markers of diabetes risk, Dr Kovil explains, adding, “Body fat percentage, and visceral and ectopic fat measurement can provide a far better insight into metabolic risk than BMI. Triglyceride-to-HDL ratio, triglyceride-glucose (TyG) index, and postprandial lipid tests are also strong predictors of future diabetes and cardiovascular disease.” India, the diabetes capital of the world, is seeing a paradigm shift in diabetes understanding with the recognition of phenotypes such as Type 3 (connecting diabetes with Alzheimer’s disease), Type 4 (in lean, elderly folk) and Type 5 (owing to childhood malnutrition), all having atypical metabolic profiles. A recent study by doctors at Pune’s BJ Govt Medical College reported the case of a male infant, born at 27 weeks and weighing 720 gm, who had frequent urination and no weight gain despite regular breastfeeding. “We presumed it was Type 1 diabetes but went for a gene test,” says study author Dr Pragathi Kamath. “During the early neonatal period, the baby developed persistent hyperglycaemia due to insulin deficiency — an extremely rare condition called Neonatal Diabetes Mellitus (NDM). Despite needing insulin therapy initially, the baby’s diabetes resolved spontaneously, confirming diagnosis.” Genetic testing revealed a homozygous mutation (identical mutated gene inherited from both parents) in MS4A6A, a gene never associated with NDM before. “The case highlighted that a newborn’s genetic profile is crucial to know the true cause of diabetes and prevent lifelong insulin therapy,” adds Dr Kamath. The study was published in the journal Cureus.Other diagnostic tools include dual-energy X-ray absorptiometry (DEXA), an imaging technique being repurposed to quantify visceral fat, a significant risk factor for metabolic syndrome and Type 2 diabetes. Visceral fat is also associated with increased secretion of pro-inflammatory cytokines and adipokines, leading to insulin resistance and beta-cell dysfunction. Dr Kovil says continuous glucose monitoring (CGM) offers a powerful early tool, revealing post-meal excursions, glycemic variability, and time-above-range long before conventional criteria are met. While fasting insulin levels are a hallmark of Type 2 diabetes, offering insight into degree of insulin resistance, Hyperinsulinemic-Euglycemic Clamp Technique remains the gold standard for assessing insulin sensitivity for the whole body. Although glucose-based criteria are necessary for diagnosis, experts insists that in order to differentiate between types, clinicians must use context, history, phenotype, and autoantibodies or C-peptide tests, when needed.