Diabetes: a dynamic disease

The distinction between type 1 and type 2 diabetes was described as early as 500–600 BC by Indian physicians Sushruta and Charaka—type 1 being associated with onset in youth, and type 2 linked to obesity. Today, diabetes is recognised as a complex and heterogeneous disease that can affect people at different life stages. As such, the classic phenotypes of age of onset and metabolic features that once helped to define the types of diabetes are now far less useful clinical indicators. Modern appreciation of the heterogeneity of diabetes is not simply a product of a deeper understanding of the genetics, risk factors, and pathophysiology of the disease. A constellation of changing lifestyles, technology, and societal development has spurred an unprecedented global epidemic of diabetes over the past 40 years. This epidemic has also driven emergence of new phenotypes, in particular for type 2 diabetes, and a disturbing shift in the demographics of affected populations. The diversity of content in this issue of The Lancet—published to coincide with the 77th Scientific Sessions of the American Diabetes Association in San Diego, CA, USA, June 9–13—reflects the heterogeneity of diabetes and its management across different forms of the disease, including type 1, type 2, and gestational diabetes, as well as over the life course. In a Seminar, Sudesna Chatterjee and colleagues provide a comprehensive overview of screening and diagnosis, prevention, and challenges in the management of type 2 diabetes in adults. In addition to lifestyle interventions, they discuss the effects of glucose-lowering drugs on microvascular and macrovascular outcomes, and the fine balance between achieving aggressive glycaemic control targets and risk of severe hypoglycaemia. Understanding the complex interactions between genetics, environment, and phenotypes that drive diabetes could lead to the development of personalised therapies. Obesity is one of the strongest risk factors for type 2 diabetes. And as sedentary lifestyles and unhealthy eating habits have led to an increase in incidence of obesity among children and adolescents, so too has the incidence of adolescent type 2 diabetes risen. Russell Viner and colleagues review the emerging evidence for adolescent type 2 diabetes. The rise in prevalence of adolescent-onset type 2 diabetes is alarming, not only from the perspective of managing a chronic condition for potentially upwards of 60 years, but also because these patients seem to have a particularly aggressive disease compared with adult-onset disease and type 1 diabetes in patients of similar age. Management of adolescent type 2 diabetes must account for social considerations, such as peer acceptance and managing diabetes at school or university, as well as treating the aggressive clinical manifestations of the disease. Furthermore, many drug therapies currently used to treat adults with type 2 diabetes have not been tested in adolescent populations and are not approved for use in these patients. Viner recommends establishing specialised centres for managing adolescents with diabetes. One such example is the Young Adult Diabetes Service at the Royal Prince Alfred Hospital Charles Perkin's Centre in Sydney, NSW, Australia, where the majority of patients are from low-socioeconomic backgrounds and are of Indigenous, Asian, or Pacific Island heritage. These patients require culturally tailored interventions to encourage patient adherence and regular attendance, as well as specialised medical care. Although the types of diabetes have distinct aetiologies, there can be commonalities in the management of comorbidities. The CLARITY study, a randomised controlled trial of aflibercept versus panretinal photocoagulation for diabetic retinopathy in patients with type 1 or type 2 diabetes, is one such example. Infants born to mothers with diabetes (either pre-existing or gestational) in pregnancy are at increased risk of hypoglycaemia and the likelihoood of being exclusively breastfed is reduced. Pregnant women with diabetes are encouraged to express breastmilk in an effort to reduce these risks, but with little evidence to support the safety of this practice. The DAME study now provides reassuring data for the safety of expressing and storing breast milk late in pregnancy for women with diabetes at low risk of complications. A wealth of evidence demonstrates that the spectrum of diabetes and its complications are highly varied across disease types—and through the life course. Diagnosis and management of diabetes are compounded by the emergence of new phenotypes, particularly in adolescents. As understanding of pathophysiology of diabetes deepens, so too should the realisation that the disease itself is evolving. Clinical management strategies must rapidly adapt to meet the unique and dynamic needs of each and every patient with diabetes. Clinical efficacy of intravitreal aflibercept versus panretinal photocoagulation for best corrected visual acuity in patients with proliferative diabetic retinopathy at 52 weeks (CLARITY): a multicentre, single-blinded, randomised, controlled, phase 2b, non-inferiority trialPatients with proliferative diabetic retinopathy who were treated with intravitreal aflibercept had an improved outcome at 1 year compared with those treated with PRP standard care. Full-Text PDF Advising women with diabetes in pregnancy to express breastmilk in late pregnancy (Diabetes and Antenatal Milk Expressing [DAME]): a multicentre, unblinded, randomised controlled trialThere is no harm in advising women with diabetes in pregnancy at low risk of complications to express breastmilk from 36 weeks' gestation. Full-Text PDF Type 2 diabetes415 million people live with diabetes worldwide, and an estimated 193 million people have undiagnosed diabetes. Type 2 diabetes accounts for more than 90% of patients with diabetes and leads to microvascular and macrovascular complications that cause profound psychological and physical distress to both patients and carers and put a huge burden on health-care systems. Despite increasing knowledge regarding risk factors for type 2 diabetes and evidence for successful prevention programmes, the incidence and prevalence of the disease continues to rise globally. Full-Text PDF Type 2 diabetes in adolescents: a severe phenotype posing major clinical challenges and public health burdenType 2 diabetes in adolescence manifests as a severe progressive form of diabetes that frequently presents with complications, responds poorly to treatment, and results in rapid progression of microvascular and macrovascular complications. Although overall still a rare disease, adolescent type 2 diabetes now poses major challenges to paediatric and adult diabetes services in many countries. Therapeutic options are heavily curtailed by a dearth of knowledge about the condition, with low numbers of participants and poor trial recruitment impeding research. Full-Text PDF Elizabeth Mayer-Davis: leader in adolescent diabetes“Doing a lot of seemingly different things that are actually connected”, is the way that Elizabeth Mayer-Davis describes working life as Chair of Nutrition at the University of North Carolina at Chapel Hill, NC, USA. She is currently prioritising research into glycaemic control and weight management in type 1 diabetes; and soon hopes to be working on a trial to investigate how an automated insulin delivery system (the so-called bionic pancreas) will impact on diet and bodyweight. “When it comes to research, I try and see where the gaps in research lie, and work out where I can make a difference”, she says. Full-Text PDF