Introduction

There is substantial evidence that diabetic neuropathy (DN) leading to foot ulceration (FU) is associated with increased morbidity and increased risk of mortality. Previous estimates of the prevalence of diabetic peripheral neuropathy vary widely due to the different diagnostic criteria employed and study populations involved.1,2

Since a definition of DN was obtained in the San Antonio Conference3 and a more clinical approach to the diagnosis was suggested later by the Neurodiab subcommittee of the European Association, there have been only a few population-based studies that have examined the prevalence of this disorder and foot ulceration.3 However, such studies are important when a large population sample size is captured and a high response rate is obtained. These types of studies can give valuable information regarding the actual prevalence of the disease in the whole community. Furthermore, the studies that have been published so far have reported different prevalence rates and also different risk factors for DN and FUs.4–10

The aim of the present study was to estimate the prevalence of diabetic chronic sensorimotor neuropathy and foot ulceration in a geographically well-defined diabetic population and to evaluate the potential risk factors.

Patients and Methods

Patients who had already been diagnosed with diabetes, age 18 to 70 years, were eligible for enrollment in the study. All patients were living in the same prefecture in Northern Greece. Patients with other diseases known to cause neuropathy, such as pernicious anemia, were excluded from the study.

Eight-hundred and twenty-one diabetic patients (306 men, 781 type 2) were studied. They represented 80 percent of the known diabetic population in this area (as estimated in a previous study).11 Mean age was 60 years (59.5 ± 7.96) and the mean known duration of diabetes was 7.6 ± 6.9 years. All the patients were examined by a single observer.

Painful symptoms of neuropathy were assessed using a modified neuropathy symptom score (NSS) based on the original system proposed by Dyck.12 More specifically, the patients were asked if they had experienced at any time the following symptoms: pins and needles, abnormal cold or hot sensations in their feet, aching pain, burning pain, and irritation in their feet and legs by the bedclothes at night (paresthesia). One point for the presence of each of these symptoms was assigned. For the first five symptoms one extra point was added if nocturnal exacerbation was present.

The Neuropathy Disability Score (NDS) was used to quantify the severity of diabetic neuropathy on clinical examination. The sensations of pain, touch, cold, and vibration were tested in both legs of all patients and were scored according to the level up to which the sensation was impaired (from 1 for toe up to 5 just below the knee). The reflexes were scored in every leg as normal (0), present with reinforcement (1), and absent (2). A NDS greater than five (maximum 28) was considered abnormal.12 The VPT was measured at the great toe of the dominant side using a Bio-Thesiometer (Biomedical Instrument, Newbury, Ohio, USA). The mean value after three readings was recorded as previously described.13

Peripheral neuropathy was diagnosed when at least two of the three quantitative measurements (NSS, NDS, and VPT) were abnormal. Retinal status was assessed from a single funduscopy. Fasting plasma glucose values were obtained from the medical records. Foot pulses were recorded as either present or absent. The absence of one or more pulse, presence of claudication, and/or a history of previous revascularization was regarded as diagnostic for peripheral vascular disease (PVD). The existence of a foot ulcer or history of previous ulceration was also recorded.

Statistical Analysis

For the univariate analysis, the chi-square test and student t-test were used.