ADA: Neuropathy Most Likely to Strike in Type 2 Diabetes

CHICAGO, June 27 -- Painful neuropathy is more common in patients with type 2 diabetes than in those with type 1, possibly, researchers suggest, because of a link with the metabolic syndrome.
In an observational study, painful diabetic polyneuropathy was three times more common among type 2 patients than type 1 patients (17.9% versus 5.8%), reported Ides M. Colin, M.D., Ph.D., of CHR-S. Joseph Medical Center in Mons, Belgium, and colleagues.
This type of neuropathy was independently associated with three components of the metabolic syndrome-obesity, low HDL cholesterol, and high triglyceride levels -- they said at the American Diabetes Association meeting here.
"The higher prevalence of diabetic polyneuropathy in type 2 diabetic patients could be due to the involvement of metabolic syndrome-associated disturbances," they wrote.
Because the epidemiology of painful diabetic polyneuropathy had not been well characterized, the researchers conducted a cross-sectional study that included 1,111 patients at 40 Belgian diabetes clinics; 344 had type 1diabetes and 767 had type 2.
The researchers tested for neuropathy in patients' feet using a monofilament for sensory perception and a device called the Neuropen for pain sensation. Participants also completed a questionnaire on characteristics of the pain sensation.
Nearly half of the patients overall complained of pain on the visual analog scale. Patients with type 2 diabetes reported it more frequently than did those with type 1 (53.6% versus 34.9%).
The occurrence of diabetic polyneuropathy was significantly higher among type 2 diabetes patients than type 1 patients (50.8% versus 25.6%, P=0.0007).
The prevalence of painful diabetic polyneuropathy showed the same significant difference (17.9% versus 5.6%).
Factors associated with higher diabetic neuropathy in a multivariate analysis were male gender (P=0.02), increasing age (P<0.0001), type 2 diabetes (P=0.02), increasing duration of the disease (P=0.0006), and HDL cholesterol at or below 40 mg/dL for men or 50 mg/dL for women (P<0.0001).
The strongest predictors of neuropathy in a bivariate analysis were foot problems (odds ratio 10.5, P<0.0001) and low HDL cholesterol (OR 2.14, P<0.0001).
Independent predictors of painful diabetic neuropathy were:
Low HDL cholesterol (OR 2.17, 95% confidence interval 1.38 to 3.41, P=0.0008).
Triglyceride levels at or above 150 mg/dL (OR 1.76, 95% CI 1.13 to 2.75, P=0.01).
Obesity (OR 1.62, 95% CI 1.05 to 2.49, P=0.03).
Nephropathy (OR 1.69, 95% CI 1.10 to 2.59, P=0.02).
Age (OR 1.47 per decade, 95% CI 1.20 to 1.81, P=0.0003).
Diabetes duration (OR 1.14 per five years, 95% 1.02 to 1.28, P=0.02).
The researchers concluded that neuropathy and painful neuropathy are mainly associated with type 2 diabetes, potentially via the metabolic syndrome, which encompassed the majority of the strong predictors found.