The Prevalence and Associations of Diabetes Peripheral Neuropathy Among Diabetic Patients Registered in Medical Clinics at the National Hospital of Sri Lanka

Introduction: Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes, affecting up to 50%. DPN is associated with foot ulcers which can result in amputations. Early diagnosis is the key strategy to prevent foot ulcers.
Objective: This study aimed to determine the prevalence of DPN and its associated factors among patients with Diabetes mellitus (DM) registered in medical clinics at the National Hospital of Sri Lanka.
Methodology: This was a descriptive cross-sectional clinic-based study. We randomly selected 280 participants with diabetes. Michigan Neuropathy Screening Instrument (MNSI) was used to screen for DPN. MNSI is a simple validated clinical tool consisting of two parts: MNSI symptom score and MNSI examination score. An MNSI examination score of > 2 was taken as the cut-off point for defining DPN, which was 80% sensitive and 95% specific.
Results: Females were the majority (62.5%, n= 280). The mean age was 58.6 years, and the mean duration of diabetes was 8.6 years. Type 2 diabetes was the vast majority (96.1%). 120 patients (42.9%) had DPN according to the MNSI examination score. However, only 59 patients (21.1%) were diagnosed as having DPN. There was no significant difference in the incidence of DPN among different ethnic groups. However, the duration of diabetes was very significantly associated with DPN (p =0.001). Only 14 patients (5%) had an MNSI symptom score of 7 or more, but all of them had DPN (MNSI examination score > 2). The most common symptom was numbness of the feet (n=95); the sign was reduced vibration sensation (n=101, 36.07%). Nevertheless, a significant number of patients (26.3%) with feet numbness,36.7% with burning pain in the feet, and 26.7% with prickling sensation in the leg did not have DPN (MNSI examination score < 2). Conversely, 34 patients (28.3%) with DPN were asymptomatic There were 8 (0.03%) patients with leg ulcers, 7 of whom had DPN. The most common comorbidity in this study group was hypertension (n=205, 73.2%). Peripheral vascular disease (p=0.011) and retinopathy (p=0.016) were significantly associated with DPN.
Conclusion: DPN is a common and important complication of diabetes, however, a significant percentage of patients with DPN were not diagnosed at clinics. Many patients with DPN had no symptoms, therefore symptomatology in DPN is not a reliable clue to the diagnosis. Consequently, we reiterate the importance of annual assessment using a simple screening tool such as the MNSI examination score in patients with diabetes.