Most people have never heard of Ketosis Prone Diabetes: Here is what you need to know

Clinicians once assumed that diabetic ketoacidosis (DKA) only occurred in Type 1 diabetes. So when middle-aged, high-body-weight people of African and Caribbean origin presented with DKA, they were diagnosed with Type 1 diabetes even though they didn’t fit the age or weight category: they were older and more overweight than expected. We now know that Ketosis-prone or Flatbush diabetes, an atypical form of diabetes, should have been the diagnosis. But what does it refer to exactly?

Key points

  • ‘Flatbush’ or ketosis-prone Type 2 diabetes (KPD) is common in black and Caribbean populations.
  • KPD is defined as diabetes which commences with ketoacidosis in individuals who are GAD65 and anti-islet cell antibody negative
  • KPD has short-term symptoms in common with Type 1 diabetes, and long-term symptoms in common with Type 2 diabetes
  • People living with KPD are prone to ketoacidosis, a potentially life-threatening condition that occurs due to insufficient insulin production in the body. Symptoms include nausea, vomiting, stomach pain, confusion etc
  • The factors responsible for the development and remission of KPD remain unknown.
  • The name “Flatbush” comes from the American community where this subtype of diabetes was first identified. Flatbush is a predominantly black migrant community housing people of African and Caribbean origin.

What is ketosis-prone Type 2 diabetes?

Ketosis-prone Type 2 diabetes blurs the lines between Type 1 and Type 2 diabetes and is often described as an ‘atypical’ subtype of diabetes. If refers to a form of the condition that commences with ketoacidosis in individuals who have no known precipitating causes: their GAD65 and anti-islet cell antibody tests return negative results.  

Ketosis-prone Type 2 diabetes was first identified in the 1980’s among African Americans residing in the ethnically diverse neighborhood of Flatbush in Brooklyn, New York. For this reason, it is also referred to as Flatbush diabetes. While presenting with DKA at the time of their diagnosis, the patients ultimately experienced a clinical course resembling that of Type 2 diabetes. Also described as a form of ‘Type 1.5 diabetes’ or ‘temporary diabetes’, this manifestation of diabetes has been the subject of a growing number of studies.  

While the early clinical studies focused particularly on African American, African, and Caribbean individuals, KPD has been characterized as an “emerging worldwide clinically important entity”, particularly in Sub-Saharan African, Asian, Indian, and Hispanic populations.  

Symptoms of diabetic ketoacidosis (DKA)

Ketosis-prone Type 2 diabetes initially presents with high blood glucose levels and diabetic ketoacidosis (DKA). DKA is a potentially fatal condition that occurs when insulin production in the body is insufficient. As a result, glucose can’t enter the cells, so the body converts fatty acids into acidic ketone bodies as an alternate source of fuel. In high levels, ketones in the body can cause the breath to have a fruity odour, but also lead to: 

  • stomach pain 
  • nausea and vomiting 
  • breathlessness 

These are some of the symptoms that Hope*, a 45-year-old security guard of Nigerian descent, experienced during one of the COVID-19 lockdowns in the UK. He had been diagnosed with Type 2 diabetes two years earlier but had displayed excellent control until then. Seven days prior to his visit to the hospital, he experienced headaches, vomiting and a frequent need to urinate. Dramatically, he also lost 4kg over a very short period.  

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Dr Glennis Williams, a GP with a special interest in Diabetes and Medical education, at Grove Park Terrace Surgery in London, UK, is familiar with this case of ketone-prone diabetes. “This episode for him” she explains “was triggered by the reduced activity due to the COVID-19 restrictions and the fact that he consumed six cartons of pineapple juice over a 4-day period.” Hope realized later that he had been consuming excess sugar, which had in turn triggered this acute episode. After changing his diet, he developed recurrent hypoglycaemia and had to be taken off insulin.  

According to Dr Gideon Mlawa, consultant physician and endocrinologist at Queen’s hospital, London, patients presenting with ketosis-prone diabetes show significant improvement after insulin administration brings blood glucose levels down to a normal range. In long-term care, the patients may be taken off insulin and can be managed with diet alone, or diet and oral medications like in many Type 2 diabetes cases.  

As the symptoms of Flatbush diabetes are dynamic, Dr Mlawa encourages healthcare professionals to be mindful when working with people of African and Caribbean origin. “If they [people of African or Caribbean origin] present with high blood ketones, a high body weight, and become insulin independent following an initial Type 1 diabetes diagnosis, that is a sign that they might have Flatbush or a ketone-prone subtype of diabetes,” he adds.  

How to get tested for ketone-prone diabetes

To fully confirm that the patient has ketone-prone diabetes, Dr Mlawa says that GAD65 and anti-islet antibody tests should be done. This is because a negative antibody test confirms ketone-prone diabetes, and differentiates it from latent autoimmune diabetes in adults (LADA), a slow-progressing form of autoimmune diabetes generally found in adults.  

The specific factors responsible for the development and remission of Flatbush diabetes remain unknown. However, Dr Mlawa says that when clinicians see ethnic minority patients presenting with DKA, they must start them on insulin rather than waiting for confirmation of ketone-prone diabetes. That way they won’t miss the diagnosis if it turns out to be Type 1 diabetes.  “After initial therapy, and patient’s life has been saved, then follow-up and treatment adjustments can be made,” he adds.  

This article was written following a virtual event series organised by Diabetes Africa. Novo Nordisk provided sponsorship to support the costs of running the virtual event series. Novo Nordisk did not have any input into selection of speakers, programme content or agendas.  

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