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SA JOURNAL OF DIABETES & VASCULAR DISEASE
RESEARCH ARTICLE
VOLUME 17 NUMBER 1 • JULY 2020
11
cannot be recommended for screening in many of the hospitals
in developing countries. A number of simple methods that are
easy to use for regular screening are advocated, however, for early
detection of DPN. This early recognition is essential to prevent foot
ulceration in patients with diabetes.
Hence,inresource-constrainedenvironments,theuseofinstruments
such as neuropathy symptoms score, neuropathy examination score
and the monofilament for detection of neuropathy among patients
with diabetes is valuable. The monofilament is a non-invasive,
inexpensive, easy-to-use and portable instrument for assessing the
loss of protective sensation and it is recommended by several practise
guidelines, including the American Diabetes Association,
20
to detect
peripheral neuropathy in otherwise normal feet.
Early recognition of ‘foot at risk’ with the aim of arresting its
progression to advanced foot ulcer is an important preventative
measure to reduce the prevalence of amputation among individuals
with diabetes, preserving quality of life and ameliorating the social
and economic costs of diabetic foot disease. Hence this study aimed
to determine the frequency and patterns of peripheral neuropathy
and other risks that predispose to foot ulcerations among diabetic
patients in south-west Nigeria.
Methods
This was a cross-sectional, descriptive study carried out at the
diabetic clinic of LAUTECH teaching hospital, Ogbomoso, south-
west, Nigeria. All adult diabetes mellitus patients who attended the
diabetes clinic for follow-up visits during the study period, met the
inclusion criteria and gave their consent, were included in this study.
The purpose, nature and significance of the study were explained
to each of the participants. The study was approved by the ethics
and research committee of the hospital and informed consent was
obtained from the study participants.
The main inclusion criteria for selection were being a known
diabetic patient who had made at least three visits to the out-patient
diabetes clinic, was aged 30 years or older, and with a confirmed
diagnosis of type 2 diabetes mellitus based on WHO criteria of
a fasting plasma glucose (FPG) level of ≥ 126 mg/dl (7 mmol/l).
21
Exclusion criteria included patients with gestational diabetes and
those with amputation due to trauma, or conditions other than
diabetes.
The age, gender, marital status, level of education, duration
of diabetes, presence of hypertension and smoking history were
obtained from the patients using a proforma questionnaire specifically
designed for the study. Anthropometric measurements including
body weight (kg), body height (m), and waist and hip circumferences
(cm), measured with a non-stretchable measuring tape, were made.
The height was measured, without shoes, to the nearest 0.1 cm
on a stadiometer, and weight was measured, while wearing light
clothing, to the nearest 0.1 kg using a standard bathroom scale.
The body mass index (BMI) was calculated as weight (in kg)
divided by the square of the height (in m). The WHO classification
was used to estimate the degree of obesity.
22
Waist circumference
was used to assess central obesity, and was measured from midway
between the lower border of the ribs and the iliac crest on the
mid-axillary line, while hip circumference was taken as the widest
diameter over the greater trochanters.
Blood pressure was measured in the left arm after participants
had been seated for at least five minutes, using a digital
sphygmomanometer (Omron M X2 Basic, Omron Health Care
Co, Ltd, Kyoto Japan). Hypertension was defined as systolic blood
pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg
and/or concomitant use of antihypertensive medications.
23
The average of three most recent FPG values was used, as
less than one-third of the study participants had had glycated
haemoglobin (HbA
1c
) tests. Good glycaemic control was assumed
with a FPG level of ≤ 8.0 mmol/l.
The feet of each study participant were examined to identify
diabetes-related lesions and other features on the foot that could
predispose them to foot lesions in future. The appearance of the feet
and inspection of the lower limbs for skin status (colour, thickness,
dryness, cracking, trophic changes, loss of skin integuments), bony
deformities (such as claws, hammer toes and callus), abnormal nails
(colour, thickness, trophic changes), and other features (such as
fissures, blistering, oedema, ulceration, gangrene and amputations)
were then noted.
A peripheral neuropathy assessment was carried out with the
use of the diabetes neuropathy symptoms score (DNS) as previously
described.
24
The interviewer assessed five variables on both feet
and counted the total points (0–10). A DNS score greater than two
on the 10-point scale was considered neuropathic.
23
The diabetes
neuropathy examination (DNE) score, which is a modification of
the neuropathy disability score of Dyck, consists of eight items, two
testing muscle strength, one a tendon reflex, and five sensations.
25
The maximum score is 16 but a score of more than three points is
considered abnormal.
Light touch/pressure perception was assessed using the 5.07-
or 10-g Semmes-Weinstein monofilament examination (SMWE),
where the monofilament is applied perpendicularly to the test sites
on each foot. The end of the filament is pressed on the plantar
surface of the feet with enough pressure to cause the monofilament
to buckle. A ‘yes–no’ method is used, meaning that the patient says
yes each time he/she senses the application of the monofilament.
The ability to correctly sense the monofilament on each site was
defined as normal, whereas the inability to sense the monofilament
correctly in one or more trials was defined as disturbed. Abnormality
was assumed with insensitivity in at least four out of the 10 sites.
The 128-Hz tuning fork was struck against the palm of the
tester’s hand so that it would vibrate for approximately 40 seconds,
and then applied to the base of the forehead so that participants
could understand the concept of the vibration sensation. After
asking the patient to close his/her eyes, the tuning fork was placed
on the bony prominence at the dorsum of the first toe, which is
just proximal to the nail bed. The participant was asked to report
when the vibration stopped, and the tester dampened the tuning
fork with the other hand. One point was assigned for each correct
perception of vibration (‘on’ or ‘off’). The procedure was performed
twice on each foot in such a way that the participants could not
anticipate the tester’s actions. This is a rule-out test for the presence
of neuropathy and does not indicate risks related to future onset.
Statistical analysis
The Statistical Package for Social Sciences version 17.0 (SPSS Inc,
Chicago, IL, USA) was used for data analysis. The data were cross
checked for data-entry errors. The results were initially analysed
by descriptive statistical methods, including mean and standard
deviation (SD). The independent
t
-test was used to ascertain
the association between outcome variables of diabetic foot
complications and their determinants (relevant clinical variables).
Statistical significance was set at
p
< 0.05.