The silent epidemic: how many diabetes cases are we missing in primary care?

Internal Medicine · General Medicine

What if a seemingly healthy patient sitting across from a primary care physician already had diabetes but did not know it? With no obvious symptoms to prompt investigation, could the condition remain undetected until complications emerge?The World Health Organization (WHO) states that approximately 830 million people worldwide are affected by diabetes, with the majority residing in low- and middle-income countries.[1] Undiagnosed diabetes is estimated to affect 58.7%, 45.5%, and 28.9% of adults living with diabetes in low-income, middle-income, and high-income countries, respectively. Globally, 86.9% of all undiagnosed cases are concentrated in low- and middle-income countries, where approximately four-fifths of the world's population resides.[2]However, treatment is not being received by more than half of those living with the condition. Over recent decades, steady increases have been observed in both the number of people affected by diabetes and the number of untreated cases. Diabetes mellitus is a growing global health challenge, but its true burden extends beyond diagnosed cases. Often developing silently, type 2 diabetes can remain undetected for years, delaying treatment and increasing the risk of cardiovascular disease, kidney damage, neuropathy, and vision loss. Primary care, where opportunities for early detection are frequent, is uniquely positioned to address this diagnostic gap.These figures raise an important question for primary care: How many cases remain undetected simply because screening opportunities are missed?Why does diabetes go undetected?The absence of recognisable symptoms is one of the biggest barriers to early diagnosis. Increased thirst, frequent urination, fatigue, and unexplained weight loss may develop gradually or remain unnoticed. Consequently, patients may seek medical attention only when symptoms become troublesome or complications appear.Several additional factors contribute to missed diagnoses:Inconsistent screening: Blood glucose testing may not be prioritised during consultations for unrelated complaintsUnderestimation of risk: Diabetes may be overlooked in patients who appear healthy or do not fit the stereotypical risk profileLimited awareness: Patients may not recognise their susceptibility or understand the importance of preventive testingHealthcare access barriers: Financial constraints, limited diagnostic facilities, and infrequent healthcare visits can delay testingMissed follow-up: Abnormal screening results may not always lead to timely confirmatory testing, communication, or treatment initiationTogether, these barriers create a diagnostic blind spot in which a manageable condition can progress unnoticed.Primary care: The first line of detectionPrimary care physicians are well positioned to identify individuals at risk before symptoms develop. Routine consultations provide opportunities to assess risk factors, recommend appropriate testing, and initiate timely management.However, screening should be guided by applicable clinical guidelines and individual risk profiles. Particular attention should be given to individuals with overweight or obesity, a family history of diabetes, physical inactivity, hypertension, dyslipidemia, previous gestational diabetes, or a history of prediabetes. Age and other relevant clinical risk factors should also inform screening decisionsImportantly, the absence of symptoms should not be interpreted as the absence of disease. A structured approach to diabetes risk assessment can help clinicians identify patients who might otherwise be overlookedTurning screening into action: what can clinicians do?Closing the diabetes detection gap requires a systematic approach rather than reliance on symptoms alone. Three practical steps can help strengthen early identification in primary care.Make risk assessment routine: Incorporating diabetes risk assessment into regular consultations can help identify individuals who require testing. Opportunistic screening during visits for hypertension, obesity, cardiovascular risk assessment, or other relevant conditions can also reduce missed opportunitiesChoose appropriate diagnostic tests: Fasting plasma glucose, glycated hemoglobin (HbA1c), and the oral glucose tolerance test (OGTT) can be used to diagnose diabetes, depending on clinical circumstances, test availability, and applicable guidelines. In asymptomatic individuals, an abnormal result generally requires confirmation according to established diagnostic criteria. Where HbA1c may be unreliable because of certain haematological conditions or altered red blood cell turnover, alternative testing may be appropriateClose the follow-up loop: Screening alone is insufficient unless abnormal results lead to timely confirmation, communication, and appropriate management. Electronic health records, patient reminders, and systematic tracking of pending investigations can help minimise losses to follow-upBeyond diagnosis: Preventing the complications of tomorrowThe value of early detection extends beyond assigning a diagnosis. Timely intervention can support better glycaemic control and reduce the risk of diabetes-related complications. Lifestyle modifications, including balanced nutrition, regular physical activity, and weight management where appropriate, can form the foundation of care. Pharmacological treatment should be individualised according to the patient's clinical profile and current guidelinesEqually important is the identification of associated cardiovascular and renal risk factors. Blood pressure, lipid levels, kidney function, and other relevant parameters should be assessed as part of comprehensive diabetes managementFor primary care physicians, the goal is not simply to detect more cases but to ensure that every diagnosis becomes an opportunity for effective, continuous careConclusion: Every missed diagnosis is a missed opportunityThe global burden of undiagnosed diabetes highlights a critical gap between the number of people living with the condition and those receiving appropriate care. By recognising risk factors, integrating appropriate testing into routine practice, and ensuring timely follow-up, clinicians can help uncover hidden cases before complications arise.Every consultation presents an opportunity to look beyond the presenting complaint. Every appropriate test can bring an undiagnosed patient closer to care. And every timely diagnosis can be a meaningful step towards reducing the long-term burden of diabetes.Reference(s):1. Diabetes. World Health Organization (WHO). 2026 https://www.who.int/health-topics/diabetes#tab=tab_12. Magliano DJ, Boyko EJ; Diabetes Atlas 11th edition scientific committee. Diabetes Atlas [Internet]. 11th edition. Brussels: International Diabetes Federation; 2025 https://www.ncbi.nlm.nih.gov/books/NBK618744/