Painful and painless diabetic peripheral neuropathy prevalence in the Northern Danish Region

Aims: The diabetic peripheral neuropathy (DPN) prevalence and incidence vary significantly across studies. Epidemiological evidence regarding the phenotyping of neuropathy, painful and non-painful, is even more discordant. These epidemiological differences are caused by numerous variables: differences in populations, the type of diabetes, geographical location, health systems, definitions of DPN, and often, exclusive inclusion of patients accessing hospital and healthcare facilities. The present study aimed to estimate a questionnaire- centered prevalence of painful and painless DPN in the Northern Danish Region, to examine its geographical distribution, and to investigate associations between DPN and potential risk factors.

Methods: A questionnaire-based survey was e-mailed to all persons with diabetes, identified through The National Health Insurance Service Registry, living in the Northern Danish Region. The survey included information on demographics, socioeconomics, municipality, diabetes type, duration, and treatment, as well as the validated questionnaires Michigan Neuropathy Screening Instrument-questionnaire (MNSIq) and the Douleur Neuropathique en 4 Questions (DN4)-interview. Possible DPN was defined as an MNSIq score ≥4, while possible painful DPN was defined as pain in both feet and a DN4-interview score ≥3.

Results: 7588 subjects (33%) responded to all questionnaires among 23,206 people with diabetes. The prevalence of possible DPN was 23.3% (95% CI: 22.4-24.3%) and ranged from 22.1% to 35.0% across municipalities while the prevalence of possible painful DPN was 18.0% (17.1-18.8%), ranging from 15.6% to 20.0%. An increased risk of DPN was associated with high body mass index, long duration of diabetes, insulin use, use of glucagon-like peptide-1 analogues, and low income.

Conclusions: The study shows a high prevalence of painless and painful DPN even in a high-income country pointing to the need for better prevention and careful screening.

Comments. The prevalence of possible DPN equal to approximately 23%, and a corresponding prevalence of possible painful DPN of approximately 18% are aligned with recently published studies (Gylfadottir SS et al Pain. 2020;161:574-583; Kristensen FPB et al Diabetes Care. 2023;46:1546-1555). Among the known risk factors (high BMI, long diabetes duration, low income, and insulin use), the role of GLP1-agonist emerges unexpectedly. The Authors, recognizing a potentially protective role of GLP1 agonists on neuropathy, consider this association weak and consequent to the characteristics of the subjects who take this pharmacological category (higher BMI, hypertension, or hypercholesterolemia) rather than an effect of the GLP1-agonist itself. The study also examined regional differences in the prevalence of DPN, revealing a trend towards lower prevalence around the two largest cities, Aalborg and Hjoerring. The study's main strengths were the high quality of the Danish national/regional registers, the large population, and the risk factors assessment. The weaknesses were that the study excluded all those without digital mail, resulting in an underestimation of the prevalence. Secondly, the DPN prevalence was based exclusively on symptom-based questionnaires. Thirdly, the response rate was limited to approximately one-third of the population. Fourthly, the study lacked laboratory data, other diabetes complications, and the duration of medical treatments that could influence the reported associations.

Fabiana Picconi

Reference. Røikjer J, Wegeberg AM, Nikontovic A, Brock C, Vestergaard P. Prevalence of painful and painless diabetic peripheral neuropathy in the Northern Danish Region: A population-based study. Prim Care Diabetes. 2024 Aug 30:S1751-9918(24)00164-5. doi: 10.1016/j.pcd.2024.08.006. Epub ahead of print. PMID: 39217071.

https://www.primary-care-diabetes.com/article/S1751-9918(24)00164-5/fulltext