Cardiovascular Risk Factors Predicting the Development of Distal Symmetrical Polyneuropathy in People with Type 1 Diabetes: A 9-Year Follow-up Study

Utility of DN4 questionnaire in assessment of neuropathic pain and its clinical correlations in Turkish patients with diabetes mellitus

AIM

We aimed to assess the utility of DN4 questionnaire (Douleur Neuropathique en 4 questions) to define the frequency and severity of neuropathic pain (NP) and also its clinical correlation to daily clinical practice.

METHODS

We included 1357 patients with diabetes (56.5% women, 90.4% type 2 diabetes) who were followed up in our diabetes outpatient clinic. Presence of NP was evaluated by performing simultaneous DN4 questionnaires and physical examination. Those who had a DN4 score ≥4 were considered to have NP.

RESULTS

The mean age was 58.2±12.1 years, mean duration was 12.5±7.5; (min-max: 1-45) years, mean HbA1c level was 7.8±1.6% (min-max: 5-16.2%), (61.7±6.0mmol/mol; min-max: 31.1-153.6mmol/mol). Three hundred thirteen patients (23%) were diagnosed with NP using the DN4 tool. Male gender (p=0.01), receiving antihypertensive treatment (p=0.01), presence of retinopathy (p<0.001), cardiovascular disease (CVD) (p=0.01) and previously diagnosed neuropathy (p<0.001) were significantly associated with higher NP scores. Those who had increased DN4 scores were more likely to be on oral hypoglycemic agents (OHA)+insulin combinations (p<0.001), had longer diabetes duration (p<0.001) and higher HbA1c levels (p=0.001). Logistic regression model revealed that diabetes duration (OR: 1.02, 95% CI: 1.00-1.04, p=0.007), elevated HbA1c levels (1.11, 1.02-1.21, 0.015), presence of retinopathy (1.41, 1.20-1.64, <0.001), management with at least one OHA (1.47; 1.12-1.92; 0.004) or any insulin regimen (1.62; 1.16-2.27; 0.005) (compared with diet only-regimens) were significantly associated with NP.

CONCLUSION

Utilization of DN4 questionnaire in daily clinical practice is an effective tool in the identification of pain related with peripheral diabetic polyneuropathy.

The Effect of Cigarette Smoking on Diabetic Peripheral Neuropathy: A Systematic Review and Meta-Analysis

OBJECTIVE

Studies suggest that smoking may be a risk factor for the development of microvascular complications such as diabetic peripheral neuropathy (DPN). The objective of this study was to assess the relationship between smoking and DPN in persons with type 1 or type 2 diabetes.

RESEARCH DESIGN AND METHODS

A systematic review of the PubMed, Embase, and Cochrane clinical trials databases was conducted for the period from January 1966 to November 2014 for cohort, cross-sectional and case-control studies that assessed the relationship between smoking and DPN. Separate meta-analyses for prospective cohort studies and case-control or cross-sectional studies were performed using random effects models.

RESULTS

Thirty-eight studies (10 prospective cohort and 28 cross-sectional) were included. The prospective cohort studies included 5558 participants without DPN at baseline. During follow-up ranging from 2 to 10 years, 1550 cases of DPN occurred. The pooled unadjusted odds ratio (OR) of developing DPN associated with smoking was 1.26 (95% CI 0.86-1.85; I(2) = 74%; evidence grade: low strength). Stratified analyses of the prospective studies revealed that studies of higher quality and with better levels of adjustment and longer follow-up showed a significant positive association between smoking and DPN, with less heterogeneity. The cross-sectional studies included 27,594 participants. The pooled OR of DPN associated with smoking was 1.42 (95% CI 1.21-1.65; I(2) = 65%; evidence grade: low strength). There was no evidence of publication bias.

CONCLUSIONS

Smoking may be associated with an increased risk of DPN in persons with diabetes. Further studies are needed to test whether this association is causal and whether smoking cessation reduces the risk of DPN in adults with diabetes.

Cardiovascular disease predicts diabetic peripheral polyneuropathy in subjects with type 2 diabetes: A 10-year prospective study

BACKGROUND

The relationship between cardiovascular disease and diabetic peripheral neuropathy is mainly sustained by data retrieved from cross-sectional studies focused on cardiovascular risk factors. We aimed to assess the presence of cardiovascular disease as a risk factor for developing diabetic peripheral neuropathy in a type 2 diabetes mellitus population.

METHOD

A 10-year prospective, primary care, multicentre study in a randomly selected cohort. Cardiovascular disease presence included stroke, coronary artery disease and/or peripheral ischaemia. Diabetic peripheral neuropathy diagnosis was based on clinical neurological examination as well as the neuropathy symptoms score and nerve conduction studies.

RESULTS

Three hundred and ten (N=310) patients were initially recruited. Two-hundred and sixty seven (N=267) patients were included in the study. Diabetic peripheral neuropathy cumulative incidence was 18.3% (95% confidence intervals 14.1-23.4; N=49). Diabetic peripheral neuropathy development was significantly more frequent in participants presenting with cardiovascular disease at baseline (P=0.01). In the final logistic regression analysis, the presence of cardiovascular disease remained associated with an increased risk for diabetic peripheral neuropathy (odds ratio 2.32, 95% confidence intervals 1.03-5.22) in addition to diabetes duration and low density lipoprotein-cholesterol levels.

CONCLUSIONS

In our series, type 2 diabetes mellitus patients with cardiovascular disease at baseline present with an increased risk of developing diabetic peripheral neuropathy at 10 years of follow-up. Our results suggest that measures aimed at the prevention, control and treatment of cardiovascular disease can also help prevent diabetic peripheral neuropathy development.

Painful and painless diabetic neuropathy: one disease or two?

Painful diabetic polyneuropathy (PDPN) is generally considered a variant of diabetic polyneuropathy (DPN) but the identification of distinctive aspects that characterize painful compared with painless DPN has however been addressed in many studies, mainly with the purpose of better understanding the mechanisms of neuropathic pain in the scenario of peripheral nerve damage of DPN, of determining risk markers for pain development, and also of recognizing who might respond to treatments. This review is aimed at examining available literature dealing with the issue of similarities and differences between painful and painless DPN in an attempt to respond to the question of whether painful and painless DPN are the same disease or not and to address the conundrum of why some people develop the insensate variety of DPN whilst others experience distressing pain. Thus, from the perspective of comparing painful with painless forms of DPN, this review considers the clinical correlates of PDPN, its distinctive framework of symptoms, signs, and nerve functional and structural abnormalities, the question of large and small fiber involvement, the peripheral pain mechanisms, the central processing of pain and some new insights into the pathogenesis of pain in peripheral polyneuropathies and PDPN.

The assessment of clinical distal symmetric polyneuropathy in type 1 diabetes: a comparison of methodologies from the Pittsburgh Epidemiology of Diabetes Complications Cohort

Distal symmetrical polyneuropathy (DSP) is the most common type of diabetic neuropathy, but often difficult to diagnose reliably. We evaluated the cross-sectional association between three point-of-care devices, Vibratron II, NC-stat(®), and Neurometer(®), and two clinical protocols, MNSI and monofilament, in identifying those with DSP, and/or amputation/ulcer/neuropathic pain (AUP), the two outcomes of major concern. This report presents data from 195 type 1 diabetic participants of the Epidemiology of Diabetes Complications (EDC) Study attending the 18-year examination (2004-2006). Participants with physician-diagnosed DSP, AUP or who were abnormal on the NC-stat, and the Vibratron II, MNSI, and monofilament were older (p<0.05) and had a longer duration of diabetes (p < 0.05). There was no difference by sex for DSP, AUP, or any testing modality, with the exception of NCstat (motor). The Vibratron II and MNSI showed the highest sensitivity for DSP (>87%) and AUP (>80%), whereas the monofilament had the highest specificity (98% DSP, 94% AUP) and positive predictive value (89% DSP, 47% AUP), but lowest sensitivity (20% DSP, 30% AUP). The MNSI also had the highest negative predictive value (83%) and Youden's Index (37%) and currently presents the single best combination of sensitivity and specificity of DSP in type 1 diabetes.

Risk factor associations with clinical distal symmetrical polyneuropathy and various neuropathy screening instruments and protocols in type 1 diabetes

OBJECTIVE

To determine whether DSP and neuropathy-assessment instruments used by non-physicians have similar risk factors.

RESEARCH DESIGN AND METHODS

analyses were cross-sectional (n=176).

RESULTS

risk factors were similar for DSP and screening devices.

CONCLUSIONS

these data support the clinical utility of neuropathy screening devices used by non-physician personnel.

Prevalence and impact on quality of life of peripheral neuropathy with or without neuropathic pain in type 1 and type 2 diabetic patients attending hospital outpatients clinics

AIMS

Diabetic polyneuropathy (DPN) without or with neuropathic pain (DPN-P) is one of the most frequent complications of diabetes. To better delineate their respective prevalences, we conducted a cross-sectional study that included 1111 patients (767 type 2 and 344 type 1 diabetic patients) followed up in diabetic outpatients clinics. The association of DPN and DPN-P with other diabetic complications, the impact on quality of life (QoL) and pain management were also investigated.

METHODS

Two validated tools (Neuropen) and the DN4 questionnaire) were used to diagnose the two conditions. Pain intensity was measured using a visual analogue scale, and participants completed the 12-item Short-Form Health Survey to evaluate the physical and mental components of QoL. Univariate and multivariate models were used for the statistical analyses.

RESULTS

The prevalence of DPN was 43% (95% CI 40.1-45.9), and was higher in type 2 (50.8%) than in type 1 (25.6%) diabetic patients. The prevalence of DPN-P was 14% (95% CI 12.1-16.2) which, again, was higher in type 2 (17.9%) than in type 1 (5.8%) patients. These prevalences both increased with age and diabetes duration. Nephropathy, obesity, low HDL cholesterol and high triglyceride levels were independently associated with DPN and/or DPN-P. Physical and mental components of QoL were significantly altered by DPN-P, but not DPN. Only half of the DPN-P patients were using analgesic treatment, while 28% were using anticonvulsants or antidepressants.

CONCLUSION

DPN and DPN-P are frequent complications of diabetes, especially in type 2, and can be identified with inexpensive and easy-to-use screening tools. Despite its profound impact on QoL, DPN-P remains undertreated.