Diabetes Mellitus: A Comprehensive Review of Etiology, Pathogenesis, Diagnosis and Treatment Strategies

Diabetes mellitus is a chronic, multifactorial metabolic disorder characterized by persistent hyperglycemia resulting from impaired insulin secretion, defective insulin action, or a combination of both. It has emerged as one of the leading global public health challenges due to its rapidly increasing prevalence, substantial morbidity, mortality, and economic burden. The disease encompasses several forms, including type 1 diabetes mellitus, type 2 diabetes mellitus, gestational diabetes mellitus, and other specific types associated with genetic, endocrine, or drug-induced causes. The pathogenesis of diabetes involves complex interactions among genetic predisposition, autoimmune mechanisms, insulin resistance, β-cell dysfunction, chronic inflammation, oxidative stress, and environmental factors. Persistent hyperglycemia contributes to the development of microvascular complications, such as diabetic retinopathy, nephropathy, and neuropathy, as well as macrovascular complications including cardiovascular disease and stroke. Early diagnosis through glycemic biomarkers, including fasting plasma glucose, oral glucose tolerance test, glycated hemoglobin (HbA1c), and continuous glucose monitoring, is essential for preventing disease progression and associated complications. Current therapeutic strategies encompass lifestyle modifications, medical nutrition therapy, physical activity, oral antidiabetic agents, injectable therapies, insulin replacement, and emerging pharmacological approaches targeting novel metabolic pathways. Recent advances in precision medicine, continuous glucose monitoring systems, artificial intelligence-assisted diabetes management, regenerative medicine, and β-cell replacement therapies have significantly expanded the therapeutic landscape. This comprehensive review presents an updated overview of the epidemiology, classification, etiology, molecular pathogenesis, diagnostic criteria, clinical manifestations, complications, and contemporary treatment strategies for diabetes mellitus. It further highlights recent advances in disease management, preventive interventions, and future therapeutic prospects aimed at improving glycemic control, minimizing complications, and enhancing the quality of life of individuals living with diabetes.