Significance of Neutrophil to Lymphocyte Ratio (NLR) and Platelet Lymphocyte Ratio (PLR) in Diabetic Foot Ulcer and Potential New Therapeutic Targets

Diabetic foot ulcer (DFU) is a well-known complication of diabetes and a significant burden on the national health systems. The neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio are inexpensive and easily accessible biomarkers that have proved to be useful in several inflammatory, infectious and cardiovascular diseases. We carried out a comprehensive review examining the association of NLR and PLR with the onset and progression of DFU. PLR and NLR were significantly increased in patients with DFU, compared with a control group of T2DM patients without DFU, and correlate well with DFU severity, evaluated by Wagner and IWGDF grading scales. In patients with diabetic foot infections (DFI), elevated NLR and PLR were correlated with osteomyelitis, increased risk of amputation, and septic complications. The significance of the elevated value of these biomarkers in DFU is related to chronic hyperglycemia and low-grade systemic inflammation, atherosclerotic and vascular complications, and also the associated septic factor. Serial, dynamic follow-up can provide useful information in planning and monitoring DFU treatment, as well as in risk stratification of these vulnerable patients. Further randomized studies are needed to set the cut-off values with clinical significance.

The role of neutrophils in diabetic ulcers and targeting therapeutic strategies

Diabetic ulcers (DUs) are a common complication of diabetes with high morbidity, poor prognosis, and a high socio-economic burden. The main pathological manifestations of DUs are chronic inflammation, impaired re-epithelialization, and impaired angiogenesis. During the inflammatory phase, neutrophils are one of the main DU cell types and act by releasing neutrophil extracellular traps (NETs), leading to poor healing in DUs. This review summarizes the role of neutrophils in the pathology and treatment of DUs, with a view to potential novel therapies and therapeutic targets.

Basic haematological tests as inflammatory performance markers of patients treated either by conservative surgery or minor amputation for infected diabetic foot ulcers

Basic inflammatory markers have been extensively studied to differentiate between non-infected and infected diabetic foot ulcers (DFUs). Very rarely, basic haematological tests such as white cell count (WCC) and platelet counts were used as performance markers for DFU infection severity. The aim is to investigate these biomarkers in patients with DFU treated exclusively with surgery. In this retrospective comparative study, we included 154 procedures comparing a conservative surgery group (n = 66 for infected DFU) and a minor amputation group (n = 88 for infected DFU with osteomyelitis). Outcomes were set as the preoperative values of: WCC, neutrophils (N), lymphocytes (L), Monocytes (M), Platelets (P), red cell distribution width (RDW) and the ratios N/L, L/M and P/L. Area under curve (AUC) of the receiver operating characteristic (ROC) was calculated based on the diagnosis of minor amputation as a positive result. Cutoff point values with the highest sensitivity and specificity were obtained for each outcome. The highest AUC values were for WCC (0.68), neutrophils (0.68), platelets (0.7) and P/L ratio (0.69) with corresponding cut-off values of 10,650/mm3 , 76%, 234,000/mcL and 265, respectively. The highest sensitivity was for the platelet count (81.5%) while the highest specificity was for L/M (89%) and P/L ratios (87%). Postoperative values showed similar results. Simple routine blood tests could serve as inflammatory performance markers to help predict the severity of infection in patients treated surgically for infected DFU.

Relationship between systemic immune inflammation index and amputation in patients with diabetic foot ulcer

AIM

The systemic immune inflammation index (SII) is a cost-effective biomarker calculated by lymphocyte, neutrophil and platelet counts and is currently being studied in various diseases. Since there is no study examining the relationship between SII and diabetic foot ulcers (DFU) in the literature, our aim was to investigate the relationship between SII and amputation rate in DFU.

METHODS

Type 2 DM 511 patients with DFU were screened from 2017 to 2021. Laboratory data obtained on the first day of hospitalization were considered. Platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR) and SII were calculated from routine blood count. Participants were divided into two groups as amputation (Group 1) and non-amputation (Group 2).

RESULTS

Amputation rate was 18.8%. The A1c (8.80 (3.26) % vs. 9.52 (3.10) %, p = 0.007) and HGB (10.17 ± 2.16 g/dL vs. 12.05 ± 2.20 g/dL, p < 0.001) levels, and lymphocyte count (1.81 (1.16) vs. 2.05 (1.11), p = 0.015) were significantly lower in Group 1 than Group 2. The counts of WBC (14.01 (9.16) × 109/L vs. 10.41 (5.82) × 109/L), PLT (393.35 (196.98) × 109/L vs. 312.05 (141.33) × 109/L), neutrophil (11.52 (8.75) × 109/L vs. 6.93 (5.96) × 109/L), PLR (226.04 (159.24) × 109/L vs. 153.12 (101.91) × 109/L), NLR (6.64 (6.93) vs. 3.34 (3.99)) and SII (2505.86 (3957.47) × 109/L vs. 1092.50 (1476.08) × 109/L), and the levels of CRP (14.12 (12.66) mg/dL vs. 3.86 (12.63) mg/dL) and ESR (87.50 (50.50) mm/h vs. 63.00 (57.25) mm/h) were significantly higher in Group 1 than Group 2 (all p < 0.001). AUC of ROC analysis of PLR was 0.666 (95% CI, 0.604-0.728), NLR was 0.695 (95% CI, 0.638-0.752) and SII was 0.716 (95% CI, 0.661-0.772) for the predicting of amputation and the SII had the best AUC with 67.4% sensitivity and 63.3%specificty.

CONCLUSION

SII is a cost-effective and readily available marker, but alone may not be sufficient to predict the risk of amputation in DFU. In our results, the predictive role of SII alone or with other markers for future DFU and its role in predicting other chronic diabetic complications will be evaluated in extensive studies.

The Association of the Neutrophil-Lymphocyte Ratio With the Outcome of Diabetic Foot Ulcer

Introduction One of the most common lower-extremity impediments in people suffering from diabetes mellitus (DM) is foot ulceration. Neutrophil-lymphocyte ratio (NLR) is a useful measure in predicting disease-specific morbidity and mortality. Objectives The objective is to study the association between diabetic foot ulcer healing and the NLR. Methodology A prospective analytical study was conducted among 100 patients with diabetic foot ulcers admitted to a surgical ward in a teaching hospital between April and November 2022. Basic demographic details, ulcer examination, and NLR were evaluated on the day of admission, and the status of ulcers was assessed after six weeks and the outcome was compared with the NLR value. Data analysis was done using SPSS version 20 software (SPSS, Inc., Chicago, IL). Results The average neutrophils, lymphocytes, and neutrophil-lymphocyte ratio were, respectively, 94.73%, 14.97%, and 6.65%. 58% had healing ulcers, and 42% had non-healing ulcers. 44% of study subjects had NLR <6, which is normal, and 56% had NLR >6, which is abnormal. Among 58 subjects with healing ulcers, 75.9% had NLR < 6, and among 42 subjects with non-healing ulcers, 100% had NLR >6, which was statistically significant. The mean NLR in the healing group was 5.15 and in the non-healing group was 8.205; this was statistically significant. This shows an increased NLR has a predisposition towards non-healing chronic ulcers with a poor prognosis. Conclusion NLR can be used as a reliable indicator for determining the healing status of diabetic foot ulcers.

Effect of leukocyte-platelet fibrin-rich wound reconstruction followed by full-thickness skin grafting in the treatment of diabetic foot Wagner grade 4 ulcer gangrene (toe area)

This study investigated the effect of L-PRF on promoting full-thickness skin grafting for the treatment of diabetic foot ulcer wounds and attempted to characterize the mechanism. In a retrospective study, we centrifugated 10-20 ml of venous blood at 1006.2 g for 20 min. The fibrin clot between the top oligocellular plasma layer and the bottom erythrocyte layer was extracted and directly used, without compression, to cover the wound after debridement. Patients who received L-PRF before skin grafting underwent surgery earlier than patients in the control group. Skin necrosis occurred in 7 patients (28%) in the L-PRF group and 16 (64%) in the control group. The difference was statistically significant, P < .05. The postoperative infection rate in the control group (56%) was significantly higher than that in the L-PRF group (24%), P < .05. During a mean follow-up of 1 year, ulcer recurrence occurred in 9 patients (36%) in the control group compared with 4 patients (16%) in the L-PRF group, P < .05. The final amputation rate was also higher in the control group (48%) than in the L-PRF group (20%). The difference is statistically significant, P < .05. The Maryland scale score and SF-36 score of the two groups of patients after treatment were significantly better than those before treatment, and the difference was statistically significant (P < .05). The L-PRF group (94.80 ± 4.14) had better foot scores at the last follow-up after treatment than the control group (88.84 ± 5.22) (P < .05). The results showed that L-PRF played a positive role in the treatment of Wagner grade 4 ulcer gangrene with free full-thickness skin grafts.

Impact of red cell distribution width and red cell distribution width/albumin ratio on all-cause mortality in patients with type 2 diabetes and foot ulcers: a retrospective cohort study

Background

Red blood cell distribution width (RDW) has emerged as a prognostic factor for mortality in various diseases. Up to now, few studies have focused on the prognostic value of RDW in patients with diabetic foot ulcers (DFUs). This retrospective cohort study aimed to investigate the impact of RDW and RDW/albumin (ALB) ratio on all-cause mortality in patients with DFUs.

Methods

This study included 860 patients with DFUs in a tertiary academic hospital. The associations of RDW and RDW/ALB with all-cause mortality were assessed by multivariable cox regression analyses. The pairwise comparisons of receiver operating characteristic (ROC) curves were performed to compare the predictive performance of RDW and RDW/ALB ratio. Harrell’s concordance index, integrated discrimination improvement, and net reclassification improvement were used to estimate the improvements in risk discrimination.

Results

Patients with high RDW and RDW/ALB had lower overall survival rates (all P < 0.001). The multivariable Cox regression revealed that high RDW [adjusted hazard ratio (HR) 2.426, 95% confidence interval (CI): 1.557–3.778, P < 0.001] and high RDW/ALB (adjusted HR 2.360, 95% CI: 1.414–3.942, P = 0.001) were independent associated with high all-cause mortality. In subgroup analyses, the comparative analysis of ROC curves revealed that the discriminating ability of the RDW/ALB ratio was significantly superior to RDW in patients with no severe DFUs or no severe peripheral artery disease, or in young and middle-aged patients (all P < 0.05). Adding RDW and RDW/ALB ratio to base models improved discrimination and risk reclassification for all-cause mortality.

Conclusions

RDW and RDW/ALB ratio are robust and independent prognostic markers in patients with DFUs. The RDW/ALB ratio appears to be of more predictive value for mortality in younger and less severely ill patients with DFUs. Both RDW and RDW/ALB ratio can provide incremental predictive value for all-cause mortality over traditional risk factors. RDW and RDW/ALB ratio can be used to identify high-risk patients with DFUs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01534-4.

Blood Cell Count Biomarkers, Risk, and Outcomes of Ischemia-Related Lower Limb Amputations: Systematic Review

Lower limb amputations due to ischemia represent an important health care and social issue. However, there are currently no specific biomarkers able to predict the risk of amputation and postamputation complications and prognosis. We conducted a systematic review of studies investigating whether blood cell count indexes of systemic inflammation are linked to the risk and the outcome of lower limb amputations due to ischemia. Overall, in 22 studies involving 8832 patients selected for review, several blood cell count indexes, particularly the neutrophil lymphocyte ratio, showed some promise in terms of predicting amputations and general outcomes of conservative and surgical treatments, as well as postamputation complications and prognosis. However, largely due to methodological limitations, further prospective studies are required to establish the clinical utility and applicability of blood cell indexes in the routine management of patients with ischemia-related lower limb amputations.