2019, and this number is projected to grow to 700 million by 2045 (International

Diabetes Foundation 2019). This rise shall be followed by an increased incidence of

diabetes-related complications (Thibault et al. 2016). In various studies across India,

peripheral neuropathy prevalence ranges from about 10.5% to 32.2% in diabetic

patients (Maser et al. 1989). Compared to the West, it has a higher prevalence of DM

in India (Forouhi and Wareham 2014). Many studies have noted that glucose

tolerance test findings are abnormal in idiopathic PN patients. Sample of 107 patients

who were suffering from neuropathy due to some unknown reason were tested for

glucose tolerance, 13 suffered from diabetes mellitus and 36 had shown less glucose

tolerance (IGT) when compared to control (Singleton et al. 2001). A study

conducted in Sothern India indicated that the group in which glucose tolerance is

reduced displayed a substantially alleviated mean nerve conduction velocity (NCV)

compared to normal individuals (Viswanathan et al. 2004). In Indian epidemiologi-

cal studies from different areas, the average prevalence of PN in different community

studies ranged from 5 to 2400 per 10,000 populations (Trivedi et al. 2017). DPN is

considered the most common cause of neuropathy globally which affects more than

half of the people suffering from diabetes (Young et al. 1993). Indeed, about a

quarter portion of US diabetes health care spending is spent on DPN (Gordois et al.

2003). Due to various patient groups, concepts of neuropathy used, and methods of

evaluation, epidemiological experiments of diabetic neuropathy have produced

complex results (Stino and Smith 2017). Cardiovascular researchers found that the

incidence of neuropathic pain was 13.3% among patients who have diabetes versus

4.2% and 1.2% in subjects who possessed impairment in fasting glucose and

controls, respectively (Ziegler et al. 2009). About 66% of patients with type 1 diabe-

tes and 59% of patients suffering from type 2 diabetes were diagnosed with DPN

(Dyck et al. 1993). A community-based study found that 34% had signs of painful

neuropathy in 15,000 diabetes patients (Abbott et al. 2011). More recently, DPN’s

prevalence has been re-evaluated in young people with shorter durations of diabetes.

In a youth study (Hamman et al. 2014), a group of young people who are below

20 years of age with diabetes duration around 5 years was diagnosed for DPN,

indicating an extreme DPN burden even in teenagers (Jaiswal et al. 2017).

20.2.2 Pathogenesis of Diabetic Neuropathic Pain

A logical explanation is not yet available to explain why certain patients with

diabetes develop diabetic neuropathic pain while some do not. The mechanisms

leading to DNP are not well known, although the pathological effects of hypergly-

cemia are a significant factor that leads to this complication (Dobretsov et al. 2003;

Oyibo et al. 2002). Studies have shown partial peripheral sensory nerve degeneration

of the plantar hind paw skin area in diabetic neuropathic pain syndromes (Siau et al.

2006). Partial nerve fiber loss leads to hyper-excitability, spontaneous discharge, and

mechanosensitivity of nerve fibers with degenerated terminal arbors (Devor and

Seltzer 1999). Neuropathy condition causes cold and heat allodynia due to a

decrease in Aδ fibers which are cold specific and C fibers which are heat specific

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