Diabetic neuropathy is a common complication to diabetes and encompasses a heterogenous group of subtypes reflecting the heterogeneity of the nervous system. Diabetes can affect all parts of the nervous system, leading to various symptoms and signs of nerve damage and have a substantial impact on quality of life.1 A high co-existence of the various types of diabetic neuropathy has been demonstrated in a few studies.2,3 Distal symmetric polyneuropathy (DPN) is a length-dependent symmetric neuropathy4 and is the most common type of diabetic neuropathy, constituting approximately 80–90 % of all cases.4 DPN is associated with foot ulcer, lower-limb amputations and painful neuropathic symptoms.5,6

Large cohort studies including participants with different clinical characteristics have shown varying prevalence estimates of DPN ranging from 13 to 33 %.7., 8., 9. However, studies investigating prevalence of neuropathies diagnosed using different modalities in a tertiary diabetes specialist center is lacking.

Prevalence estimates for painful DPN, a subtype of DPN varies from 5 to 62 % for type 1 and type 2 diabetes.10,11

Diabetic autonomic neuropathy (DAN) comprises of dysfunctions of the autonomic nervous system, affecting various organ systems, leading to heterogenous manifestations. Cardiovascular autonomic neuropathy (CAN) is an independent risk factor for cardiovascular disease and mortality.12 For type 1 diabetes the prevalence ranges from 213% in a selected cohort without microvascular complications and treated hypertension to 449% in people with diabetes duration of 27-years. In type 2 diabetes it ranges from 214% in newly diagnosed diabetes to 13.515% for seven years of diabetes duration and 16,2 % after 15.3 years of diabetes duration16 when the cardiovascular autonomic reflex test (CARTS) assesses CAN.

Gastroparesis is another type of DAN, associated with poor glycemic control and reduced quality of life due to gastrointestinal symptoms. Prevalances are estimated to be 5 % and 1 % for type 1 and type 2 diabetes, respectively.17 Few large-scale studies have evaluated the co-existence of gastroparesis and other neuropathies.10 The DAN sudomotor dysfunction causes abnormalities in sweat production, and is a risk factor for development of foot ulcers.18 Sudomotor dysfunction has an estimated prevalence of 28 % in type 2 diabetes assessed by electrochemical skin conductance (ESC),19 while studies in type 1 diabetes are lacking.

These large variations in prevalences may be due to the heterogeneity of study cohorts and diagnostic modalities applied. Thus, there is a need for a clear contemporary overview of diabetic neuropathy prevalences.

In this study, we investigate the prevalence of diabetic neuropathy using a wide array of definitions and diagnostic modalities in individuals with type 1 and type 2 diabetes. Further, we examine the co-existences of various types of diabetic neuropathies.