Painful and Painless Neuropathies Are Distinct and Largely Undiagnosed Entities in Subjects Participating in an Educational Initiative (PROTECT Study)

Aims: We conducted a nationwide educational initiative to determine the prevalence and risk factors of diagnosed and undiagnosed painful and painless distal sensory polyneuropathy (DSPN).

Methods: Among 1850 participants, 781 had no history of diabetes (ND), 126 had type 1 diabetes (T1D), and 943 had type 2 diabetes (T2D). Painful DSPN was defined as polyneuropathy detected by bedside tests with pain and/or burning in the feet, while painless DSPN was defined as polyneuropathy with paresthesias, numbness, or absence of symptoms.

Results: DSPN was detected in 48.2% of ND, 44.3% of T1D, and 55.3% of T2D subjects. DSPN was painful, painless, or atypical in 62.1, 24.8, and 13.1% of the participants. Painful DSPN was more severe than painless DSPN. Painful and painless DSPN were previously undiagnosed in 61.5 and 81.1% of the participants, respectively. In T2D subjects, painful and painless DSPN were associated with a higher and lower BMI, respectively. Among ND participants 39.2% had HbA1c levels indicating prediabetes/diabetes.

Conclusions: Around half of participants in an educational initiative had DSPN, 62% of whom had the painful entity that correlated with BMI in T2D. Since many cases of neuropathy and diabetes remain undiagnosed, effective strategies to timely detect both conditions should be implemented.