Objectives: To study the incidence and extent of peripheral sensory neuropathy in diabetic patients without diabetic foot problems (DFPs) with <5, 5-10 and >10 years duration of diabetes using three different modalities of testing: Pin-Prick Testing, 5.07 Semmes-Weinstein Monofilament Testing (SWMT) and Rapid-Current Perception Threshold (R-CPT) measurements using the Neurometer.
Methods: Our study population consisted of 60 patients (120 feet) treated for diabetes mellitus in the Division of Endocrinology at the National University Hospital. No patient had any DFPs. Twenty-two, 21 and 17 patients had duration of diabetes of <5, 5-10 and >10 years, respectively. All patients were tested for sensory neuropathy using Pin-Prick Testing using a standardized protocol, SWMT and the Neurometer.
Results: There was a significantly higher incidence of sensory neuropathy detected by both the Pin-Prick Test and the Neurometer as compared to the SWMT. Also, in all three modalities, there was a significant increase in incidence of sensory neuropathy detected in diabetics with >5 years duration of diabetes. In addition, the Pin-Prick Test showed an increase in extent of sensory neuropathy with a longer duration of diabetes.
Conclusions: The Pin-Prick Test was found to be a simple, cheap and useful diagnostic tool for detection of sensory neuropathy in diabetics without DFPs. In addition, it could accurately delineate the extent of neuropathy in the lower limb - additional useful information not obtainable with SWMT or Neurometer. Even for patients with <5 years duration of diabetes, the incidence of sensory neuropathy detected was considerable. The incidence of neuropathy detected continued to increase with length of duration of diabetes. Hence, we recommend screening of patients for neuropathy as soon as they are diagnosed with diabetes.