A New Face of Diabetes: Type 5 Officially Recognized

Diabetes Redefined: “Type 5” Gains Official Recognition
A new type of diabetes has been formally recognized by the International Diabetes Federation (IDF) — “Type 5 Diabetes” — representing a malnutrition-related form that disproportionately affects young, lean individuals in low- and middle-income countries. This reclassification stems from years of clinical study and global awareness campaigns, and it marks a turning point in how clinicians understand, diagnose, and manage certain diabetes phenotypes outside the familiar Type 1 and Type 2 categories.

What Is Type 5 Diabetes?
The term “Type 5” refers to diabetes in individuals who are malnourished, typically non-obese youths or young adults, frequently lean, often from Asia or Africa, who develop hyperglycemia that does not behave like classic Type 1 or Type 2.

Key distinguishing features include:

• Low body mass at diagnosis — patients are lean, often with histories of malnutrition.
  
  
• Poor insulin secretion rather than primary insulin resistance, unlike Type 2.
  
  
• Lack of response to typical Type 1 or Type 2 therapeutic strategies — standard insulin therapy can cause hypoglycemia, and treatments targeting insulin resistance often fail.
  

Estimates suggest 20–25 million people globally are living with Type 5 Diabetes. Frequently, these individuals experience a devastating course: many do not survive more than a year following diagnosis if untreated or mismanaged.

Why This Recognition Took So Long
Reports of a “malnutrition-related” variant of diabetes are not new. Seventy years ago, clinicians noted similar diseases in impoverished regions — young, undernourished patients with severe diabetes. The World Health Organization (WHO) had once classified malnutrition-related diabetes as a distinct entity in the mid-1980s, but the classification was removed in 1999 due largely to insufficient evidence and follow-up studies.

Over the past two decades, accumulating data—from metabolic studies, observational cohorts, and clinical outcomes—have clarified that these cases are not simply atypical Type 1 or Type 2 disease but represent a separate pathophysiological process. Most notably, recent work has demonstrated that the issue is not insulin resistance but a profound inability to secrete insulin, setting this type apart in both mechanism and treatment response.

What Drove the IDF to Act
A coalition of researchers, led by clinicians from the Global Diabetes Institute at Albert Einstein College of Medicine (Dr. Meredith Hawkins and others), CMC Vellore in India, and teams from across Asia and Africa, pushed for renewed recognition. Their efforts hinged on:

• Clinical observations show that patients who are not obese and do not match the immune profile of Type 1, yet suffer from an insulin deficiency severe enough to require therapy.
  
  
• Longitudinal metabolic studies show progressive beta-cell failure rather than insulin resistance.
  
  
• Epidemiologic data estimating burden and mortality: this form of diabetes is common, yet vastly underdiagnosed.
  

In early 2025, a large collaboration met with diabetes experts from regional and international bodies to review diagnostic markers, treatment strategies, and definitions. The outcome: unanimous vote by the expert panel and endorsement at the IDF World Diabetes Congress that malnutrition-related diabetes should be formally designated “Type 5.”

Diagnostic and Therapeutic Implications
With formal recognition comes a need for new diagnostic and treatment guidelines. A working group has been established under the IDF, co-chaired by Dr. Hawkins, tasked with outlining best practices.

Diagnostics
Clinicians will need to consider Type 5 in the differential diagnosis when encountering:

• Young, lean patients with hyperglycemia.
  
  
• Poor or unpredictable response to standard insulin therapy or insulin resistance-targeted drugs.
  
  
• Features of malnutrition: low BMI, history of protein-energy malnutrition, deficiencies (micronutrients, etc.).
  

Lab work may need to shift emphasis toward:

• Measures of insulin secretion (e.g., C-peptide levels).
  
  
• Assessments of nutritional status: anthropometry, serum protein levels, micronutrients.
  
  
• Exclusion of autoantibodies typical for Type 1 (if available).
  

Treatment
Since insulin resistance does not appear to be the primary driver, using insulin sensitizers (like many Type 2 treatments) may be less effective. Instead:

• Insulin therapy may be needed, but dosing must be cautious to avoid hypoglycemia.
  
  
• Nutritional rehabilitation is central. Restoring adequate calories, proteins, and micronutrients may help preserve or restore β-cell function.
  
  
• Alternative agents that support β-cell survival or regeneration are potential areas for research.
  
  
• Monitoring is crucial; patients may deteriorate rapidly if misdiagnosed or managed with inappropriate protocols.
  

Global Health Perspective
Type 5 diabetes raises urgent questions about equity, recognition, and resource allocation in global diabetes care.

• Many patients live in resource-poor settings, with limited access to diagnostics (C-peptide, autoantibody panels), insulin supplies, and nutritional support.
  
  
• Because Type 5 has been undervalued historically, awareness among clinicians is low; many cases are misclassified as Type 1 or Type 2, leading to poor outcomes.
  
  
• The mortality rate is high, often within a year, when untreated or mismanaged. Formal recognition provides legitimacy, attracting funding and research to mitigate this burden.
  
  
• Public health strategies in Asia, Africa, and elsewhere may need to adjust: screening programs, diabetes registries, and policies must account for caloric deprivation and malnutrition as risk factors, not just obesity and sedentary lifestyle.
  

Challenges Ahead
While recognition is a major step, several challenges must be addressed:

• Establishing clear diagnostic criteria: What defines “malnutrition” in this context? What level of insulin secretion is pathognomonic? There is currently no universally accepted standard.
  
  
• Resource constraints in many affected areas: access to labs for C-peptide testing, autoantibody panels, and nutritional assessments can be limited.
  
  
• Treatment infrastructure: ensuring reliable insulin supply, nutrition programs, and follow-up care.
  
  
• Training of healthcare providers: Many physicians are unfamiliar with this form; the risk of misdiagnosis remains high.
  
  
• Research gaps: long-term natural history, therapeutic trials specific to Type 5, and population-based data are still limited.
  

What Clinicians Should Do Now
For endocrinologists, general physicians, and clinicians in global health, there are immediate actions:

1. Include Type 5 in Differential Diagnoses
   In lean patients, especially in malnourished settings, who have hyperglycemia but do not fit Type 1 or Type 2 profiles.
   
   
2. Order Appropriate Tests When Feasible
   Assess insulin secretion (C-peptide), nutritional markers, body composition, and, when possible, autoantibody testing.
   
   
3. Avoid Misapplication of Type 2 Therapies
   Drugs targeting insulin resistance without first confirming resistance may be ineffective or harmful.
   
   
4. Emphasize Nutritional Interventions
   Support programs addressing macro- and micronutrient deficiencies; this is not just adjunctive care but central to therapy.
   
   
5. Advocate for Research & Guidelines
   Participate in regional studies; contribute data. Engage with IDF working group outputs when they emerge; adjust local clinical practice accordingly.