Higher systolic blood pressure (SBP) and decreased low-density lipoprotein (LDL) level are associated with increased risk for peripheral neuropathy in patients with type 2 diabetes (T2D), especially in patients of European descent, according to results of a systematic review published in BMC Endocrine Disorders.
Progression of peripheral neuropathy is influenced by lipoprotein abnormalities and cardiovascular risk factors. The goals of this systematic review were to estimate the predictive value and prognostics accuracy of LDL and SBP for peripheral neuropathy in T2D and assess the association between decreased LDL and SBP and diabetic peripheral neuropathy.
Investigators searched PubMed, Embase, Wiley Online Library, Web of Science, Cochrane Library, and VIP-Google Scholar to identify all relevant studies prior to February 2019. After applying exclusion criteria, 38 articles were included in the review. A total of 355,438 patients were included (52.6% women; mean age, 60.11±10.00 years). The mean duration of diabetes was 6.50±2.80 years, mean level of LDL was 108.88±30.89 mg/dL, and mean SBP was 134.81±15.10 mm Hg. Patients were divided into 2 groups: people with T2D without neuropathy (n=309,197) and people with T2D with neuropathy but without pain (n=44,891), with an overall prevalence of 12.67% for diabetic peripheral neuropathy. Studies were further divided by continent for subanalysis: Asia (LDL, n=29; SBP, n=26); Europe (LDL, n=4; SBP n=2); and the United States (LDL, n=3; SBP, n=1). No studies in an African population were available.
A poor prognosis of peripheral neuropathy was associated with LDL and SBP (both P <.001). Patients without neuropathy had significantly lower SBP levels compared with patients who had neuropathy, and SBP level was associated with a 2.6-fold decrease in patients without peripheral neuropathy (standardized mean difference [SMD], -2.63; 95% CI, - 4.00 to -1.27; P <.001). Based on subgroup analysis, European patients with peripheral neuropathy had higher serum LDL levels (SMD, 0.16; 95% CI, -0.06 to 0.38) compared with their counterparts in the United States (SMD, 0.07; 95% CI, -0.24 to 0.37) and Asia (SMD, 0.07; 95% CI, 0.01-0.12).
The cross-sectional SBP studies performed in the European population had low heterogeneity in their results, and as such, the investigators concluded that SBP may be a high-risk factor for peripheral neuropathy in European patients with diabetes.
Inconsistent measurement techniques and different cutoffs for LDL and SBP among studies and the exclusion of articles not published in English were noted limitations of the review.
“Our pooled results provide compelling evidence of a significant positive association between LDL and SBP and race. Recently, many studies showed diabetes patients from Europe have a lower collision risk compared with their Asian and American counterparts. Consequently, collision risk for [diabetic peripheral neuropathy] drivers is affected significantly by the race in which the studies have been performed,” investigators wrote, highlighting the need for future studies to evaluate race as a factor.
Naqvi SSZH, Imani S, Hosseinifard H, et al. Associations of serum low-density lipoprotein and systolic blood pressure levels with type 2 diabetic patients with and without peripheral neuropathy: systemic review, meta-analysis and meta-regression analysis of observational studies. BMC Endocr Disord. 2019;19(1):125.