Neuropathy and Neuropathic Pain in Patients with Type 2 Diabetes Mellitus Receiving Metformin - A Cross-Sectional Study from Navi Mumbai, Maharashtra

Author(s): Kunal Lala1, Divya Lala2, Saurabh Duggad3

Metformin is reported to induce vitamin B12 deficiency and distinguishing
peripheral neuropathy due to vitamin B12 deficiency from diabetic peripheral
neuropathy can be challenging. The present study was conducted to assess and
compare the clinical presentation of diabetic patients taking metformin with those
not taking metformin using Toronto clinical scoring system (TCSS).
This cross-sectional study included 60 patients with diabetes mellitus, 30 patients
on metformin therapy (at least 6 months) and 30 patients not on metformin use.
Clinical presentation of the patients was assessed using the TCSS. Patients were
diagnosed according to the American diabetic association criteria.
The mean age of the patients in metformin and non-metformin group was 57.27
± 9.38 and 58.63 ± 10.27 years respectively. Gender distribution was observed to
be similar in both the study groups. Mean duration of diabetes mellitus was found
to be similar in both the study groups (5.4 ± 1.01 vs 5.2 ± 1.27 years) and duration
of peripheral neuropathy was also found to be similar in the two study groups (3.2
± 1.6 vs 3.3 ± 1.5 years). Numbness was observed in maximum number of cases
in both study groups. It was seen in 100 % (n = 30) patients on metformin drug
while in 90 % (n = 27) patients without metformin. Pain accounts to be
approximately 77 % (n = 23) and 24 % (n = 7) in patients on metformin and
without metformin. Neuropathic symptoms and neuropathic reflex scoring appear
to be higher common in patients on metformin as compared to those without
metformin. Mean pain score was found to be significantly higher among patients
on metformin as compared to those not on metformin (8.43 ± 2.13 vs 4.03 ±
3.13; P value < 0.001).
Our results show that patients on metformin for diabetes mellitus experience
higher neuropathic symptoms as compared to those not taking metformin.