Diabetic sensorimotor polyneuropathy is a common complication of diabetes mellitus that can lead to pain, sensory loss, foot ulcers, and disability. Early detection is important, but standard diagnostic tests such as nerve conduction studies are not always easily accessible in routine clinical practice.

This study aims to evaluate the accuracy and reliability of two simple clinical tools, the Neuropathy Disability Score (NDS) and the Neuropathy Symptom Score (NSS), for screening diabetic peripheral neuropathy. These tools are based on patient-reported symptoms and bedside neurological examination and may provide a practical alternative for early detection.

In this cross-sectional diagnostic accuracy study, adult patients with diabetes will be recruited from King Chulalongkorn Memorial Hospital. Participants will undergo clinical assessments, questionnaires, laboratory investigations, and neurophysiological testing, including nerve conduction studies, which will serve as the reference standard. The performance of NDS and NSS will be analyzed to determine their sensitivity, specificity, and overall diagnostic value.

The results of this study may support the use of simple, accessible screening tools for early identification of diabetic neuropathy, potentially improving patient care and reducing complications.

This study is an analytic cross-sectional diagnostic accuracy study designed to evaluate the performance of the Neuropathy Disability Score (NDS) and Neuropathy Symptom Score (NSS) in screening for diabetic sensorimotor polyneuropathy.

Adult patients with diabetes mellitus (type 1 and type 2) will be recruited from King Chulalongkorn Memorial Hospital. Eligible participants will undergo a standardized assessment protocol, including demographic and clinical data collection, physical examination, and laboratory investigations. Patient-reported outcomes will be assessed using validated questionnaires, including the Neuropathy Symptom Score (NSS), Neuropathy Disability Score (NDS), DN4 questionnaire, Michigan Neuropathy Screening Instrument (MNSI), and other relevant clinical tools.

All participants will undergo nerve conduction studies (NCS), which will serve as the reference standard for the diagnosis of diabetic peripheral neuropathy. Additional assessments may include quantitative sensory testing (QST), monofilament testing, hand grip strength measurement, ankle-brachial index (ABI), and body composition analysis, depending on clinical indication.

The primary objective is to determine the diagnostic accuracy of NDS and NSS compared with the reference standard, including sensitivity, specificity, and optimal cutoff values. Secondary objectives include evaluating the prevalence of neuropathy among patients with diabetes, identifying associated risk factors, and comparing clinical characteristics between type 1 and type 2 diabetes.

Statistical analysis will include descriptive statistics, group comparisons using appropriate parametric or non-parametric tests, and receiver operating characteristic (ROC) curve analysis to determine diagnostic performance. Correlation analyses will also be performed to assess associations between clinical variables and neuropathy outcomes.

The findings from this study are expected to support the use of simple, cost-effective screening tools for early detection of diabetic peripheral neuropathy in clinical practice, particularly in resource-limited settings.

Inclusion Criteria:

• Adults aged 30 to 65 years
• Diagnosed with diabetes mellitus (type 1 or type 2) by a physician
• Able and willing to provide informed consent
• Willing to undergo clinical evaluation and neurophysiological testing, including nerve conduction studies

Exclusion Criteria:

• History of other causes of peripheral neuropathy (e.g., nutritional deficiency, alcohol-related neuropathy, chronic kidney disease)
• Known neuromuscular or neurological disorders (e.g., myopathy, hereditary neuropathy, Guillain-Barré syndrome, chronic inflammatory neuropathy)
• Exposure to neurotoxic agents (e.g., drugs, heavy metals)
• Presence of lower limb conditions interfering with assessment (e.g., amputation, chronic wounds, significant edema)
• Inability to communicate or complete study procedures

Adult patients with diabetes mellitus (type 1 and type 2) receiving care at King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Participants will be recruited from neurology and endocrinology clinics and are representative of patients undergoing evaluation for diabetic peripheral neuropathy in a tertiary care setting.

De-identified individual participant data (IPD) will be shared with qualified researchers upon reasonable request, subject to approval by the principal investigator, institutional review board/ethics committee requirements, and a data use agreement to protect participant confidentiality.

De-identified individual participant data and supporting documents will be available beginning 6 months after publication of the primary results and ending 5 years after publication.

Access to de-identified individual participant data and supporting documents will be provided to qualified researchers who submit a methodologically sound proposal for analyses consistent with the study objectives and approved by the principal investigator and relevant institutional and ethics requirements. The materials available will include the de-identified participant-level dataset underlying the published results, together with the study protocol, statistical analysis plan, and data dictionary, where applicable. Requests should be submitted in writing to the principal investigator, and access will be granted after review and execution of a data use agreement through a secure data-sharing mechanism.