Men with poorly controlled type 2 diabetes are more at risk of developing peripheral neuropathy, suggests results from the TODAY study reported in the journal Diabetes Care.¹

This study aimed to investigate the association of glycemic control, sex and other risk factors on the development of diabetic peripheral neuropathy (DPN) in youth with type 2 diabetes. For this analysis, 674 participants from the Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study were selected. Their mean age was 14 years and they had been diagnosed with diabetes less than 2 years at the time of their enrolment. Participants were followed up annually for up to 15 years (mean 10.2 ± 4.5). They were tested yearly with the Michigan Neuropathy Screening Instrument (MNSI) and a 10-g monofilament exam. An MNSI-exam score >2 or MNSI-survey score ≥4 or both or correct identification of less than 8 of the 10 applications on each foot on monofilament exam was considered as diabetic peripheral neuropathy. A sustained abnormal MNSI score, defined as abnormal scores at ≥2consecutive visits, were used for analyses.

The incidence of DPN was observed to be higher in the male participants than in the female participants on MNSI (38.5% vs 27.2%) and monofilament examination (14.0% vs. 5.1%). The male participants, the older participants and those who had higher BMI were more likely to show sustained abnormal scores on the MNSI-exam. Similarly, those who had sustained abnormal monofilament exam scores were more likely to be male and therefore at higher risk of DPN.

Higher A1c was also associated with higher incidence of DPN. Increase in A1c by one unit resulted in a 15% rise in the chance of an abnormal MNSI-exam score and a 22% increase in the likelihood of an abnormal monofilament exam result.

At the start of the study, 3.1% showed an abnormal score (>2) on MNSI-exam, 7.3% had an abnormal score (≥4) on the MNSI-survey, 9.8% had an abnormal score via the MNSI-exam and/or MNSI-survey, while on the monofilament examination, 0.3% participants had an abnormal score. These scores increased during the course of the study suggestive of a rise in prevalence of DPN; 25.4% via MNSI-exam, 17.7% via MNSI-survey, 34.9% via both, and 10.0% via the monofilament examination; at year 14 of the study.

The most frequently observed abnormality on the MNSI-exam at this time was an abnormal ankle reflex (44.0%), followed by dry skin/callus (26.9%) and decrease/absence of vibration at the great toe (29.1%). On MNSI-survey, the most common reported symptom was cramps in the legs and/or feet (36.0%), followed by prickling sensations in the legs and/or feet (26.9%).

These findings shed light on the high prevalence of DPN in the youth with type 2 diabetes. When this study was started, some participants were already found to have some abnormalities on MNSI early in the course of the diabetes. This number increased as the study (diabetes) progressed in time. The risk factors for DPN were found to be glycemic control (on both MNSI and monofilament exam), older age, higher BMI, hypertension, high hs-CRP (on MNSI exam) and male sex (on monofilament exam). Besides aiming for optimum glycemic control, young adults with type 2 diabetes should be screened for diabetic neuropathy in the early stages of their disease for timely detection and prevention of this complication, which can cause considerable related morbidity in the long-term.

Reference

1. TODAY Study Group. Risk factors for diabetic peripheral neuropathy in adolescents and young adults with type 2 diabetes: results from the TODAY Study. Diabetes Care. 2021 Oct 29;dc211074. doi: 10.2337/dc21-1074.