The risk factors for diabetic peripheral neuropathy: A meta-analysis

Abstract

Diabetic peripheral neuropathy (DPN), the most common chronic complication of diabetes, has become an important public health crisis worldwide. Given that DPN is extremely difficult to treat, determining its risk factors and controlling it at an early stage is critical to preventing its serious consequences and the burden of social disease. Current studies suggest that the risk factors for diabetic peripheral neuropathy are the duration of diabetes, age, glycosylated hemoglobin A1c (HbA1c), diabetic retinopathy (DR), smoking, and body mass Index (BMI). However, most of the aforementioned studies are cross-sectional, and the sample sizes are very limited, so the strength of causal reasoning is relatively low. The current study systematically evaluated DPN's influencing factors in patients with type 2 diabetes using evidence-based medicine. Overall, 16 included studies (14 cross-sectional studies and 2 case-control studies including 12,116 cases) that conformed to the present criteria were included in the final analysis. The results suggested that the duration of diabetes (MD 2.5, 95% CI 1.71~3.29), age (MD 4.00, 95% CI 3.05~4.95), HbA1c (MD 0.48, 95% CI 0.33~0.64), and DR (OR 2.34, 95% CI 1.74~3.16) are associated with significantly increased risks of DPN among diabetic patients, while BMI, smoking, total triglyceride (TG), and total cholesterol (TC) did not indicate any risks of increasing DPN. The findings provide a scientific basis for a further understanding of the causes of type 2 diabetes complicated with peripheral neuropathy and the improvement of preventive strategies. The next step is to conduct further high-quality prospective cohort studies to validate this paper's findings.

Fig 1. Flowchart of the meta-analysis.

Fig 2. Duration of diabetes and risk of DPN.

The summary mean difference was calculated using a random-effects model. The mean difference and 95% CI for each study and the final combined results are displayed numerically on the left and graphically as a forest plot on the right. A and B are based on univariate analysis and multivariate analysis data, respectively. The sensitivity analysis results are shown in C.

Fig 3. Age and risk of DPN.

The summary mean difference was calculated using a random-effects model. The mean difference and 95% CI for each study and the final combined results are displayed numerically on the left and graphically as a forest plot on the right. A and B are based on univariate analysis and multivariate analysis data for cross-sectional studies, respectively. C showed significant differences in age in the case-control studies. The sensitivity analysis results are shown in D.

Fig 4. HbA1c and risk of DPN.

The summary mean difference was calculated using a random-effects model. The mean difference and 95% CI for each study and the final combined results are displayed numerically on the left and graphically as a forest plot on the right. A and B are based on univariate analysis and multivariate analysis data, respectively. The sensitivity analysis results are shown in C.

Fig 5. DR and risk of DPN.

The summary odds ratio was calculated using a fixed-effects model. The odds ratio and 95% CI for each study and the final combined results are displayed numerically on the left and graphically as a forest plot on the right. A and B are based on univariate analysis and multivariate analysis data, respectively.

Fig 6. Smoking and risk of DPN.

The summary odds ratio was calculated using a random-effects model. The odds ratio and 95% CI for each study and the final combined results are displayed numerically on the left and graphically as a forest plot on the right. A and B are based on univariate analysis and multivariate analysis data, respectively.

Fig 7. BMI and risk of DPN.

The summary mean difference was calculated using a random-effects model. The mean difference and 95% CI for each study and the final combined results are displayed numerically on the left and graphically as a forest plot on the right. A and B are based on univariate analysis and multivariate analysis data, respectively. A subgroup analysis was conducted on the basis of ethnicity; the results are shown in C. The sensitivity analysis results are shown in D.

Fig 8. TC and risk of DPN.

The summary mean difference was calculated using a random-effects model. The mean difference and 95% CI for each study and the final combined results are displayed numerically on the left and graphically as a forest plot on the right. A and B are based on univariate analysis and multivariate analysis data, respectively.

Fig 9. TG and risk of DPN.

The summary mean difference was calculated using a random-effects model. The mean difference and 95% CI for each study and the final combined results are displayed numerically on the left and graphically as a forest plot on the right.