Atherogenic Index of Plasma: A Potential Biomarker for Clinical Diagnosis of Diabetic Foot Osteomyelitis

Atherogenic Index of Plasma (AIP): The Most Accurate Indicator of Overweight and Obesity Among Lipid Indices in Type 2 Diabetes-Findings From a Cross-Sectional Study

BACKGROUND

This study aimed to evaluate the relationships of conventional and calculated lipid indices with obesity or overweight in patients with type 2 diabetes (T2D).

METHODS

In this cross-sectional study, all participants were categorised into three groups: normal weight (18 ≤ BMI < 25), overweight (25 ≤ BMI < 30) and obese (BMI ≥ 30). Conventional lipid indices, including triglyceride (TG), total cholesterol, LDL-C and HDL-C, were measured. Lipid indices, including the atherogenic index of plasma (AIP), non-HDL-C, TC/HDL-C, LDL-C/HDL-C, non-HLD-C/HDL-C (atherogenic index, AI) and lipoprotein combine index (LCI), were calculated. The associations of these lipid indices with obesity and overweight status were evaluated using univariate and multivariate multinomial logistic regression analyses.

RESULTS

In this study, 2661 patients with T2D, including 651 patients with normal weight, 1144 with overweight, and 866 with obesity, were recruited. According to a multinomial logistic regression analysis after adjustment for multiple confounders, the odds ratio (OR) was greater for the AIP than for other conventional and calculated lipid indices in overweight and obese patients with T2D. The AIP had a significant relationship with overweight, with an OR of 4.79 (95% CI: 1.65-13.85), and it had a significant relationship with obesity, with an OR of 13.64 (95% CI: 3.96-47.04). According to the ROC curve, with a cut-off value of 0.68, AIP could predict obesity with 82% sensitivity and 55% specificity (AUC = 0.770, 95% CI: 0.729-0.812, p < 0.001).

CONCLUSION

Compared with other conventional and calculated lipid markers, the AIP is most strongly associated with obesity and overweight in patients with T2D.

Update of biomarkers to diagnose diabetic foot osteomyelitis: A meta-analysis and systematic review

The aim of this study was to evaluate the diagnostic characteristics of biomarker for diabetic foot osteomyelitis (DFO). We searched PubMed, Scopus, Embase and Medline for studies who report serological markers and DFO before December 2022. Studies must include at least one of the following diagnostic parameters for biomarkers: area under the curve, sensitivities, specificities, positive predictive value, negative predictive value. Two authors evaluated quality using the Quality Assessment of Diagnostic Accuracy Studies tool. We included 19 papers. In this systematic review, there were 2854 subjects with 2134 (74.8%) of those patients being included in the meta-analysis. The most common biomarkers were erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and procalcitonin (PCT). A meta-analysis was then performed where data were evaluated with Forrest plots and receiver operating characteristic curves. The pooled sensitivity and specificity were 0.72 and 0.75 for PCT, 0.72 and 0.76 for CRP and 0.70 and 0.77 for ESR. Pooled area under the curves for ESR, CRP and PCT were 0.83, 0.77 and 0.71, respectfully. Average diagnostic odds ratios were 16.1 (range 3.6-55.4), 14.3 (range 2.7-48.7) and 6.7 (range 3.6-10.4) for ESR, CRP and PCT, respectfully. None of the biomarkers we evaluated could be rated as 'outstanding' to diagnose osteomyelitis. Based on the areas under the curve, ESR is an 'excellent' biomarker to detect osteomyelitis, and CRP and PCT are 'acceptable' biomarkers to diagnose osteomyelitis. Diagnostic odds ratios indicate that ESR, CRP and PCT are 'good' or 'very good' tools to identify osteomyelitis.

Diagnostic Performance of Atherogenic Index of Plasma for Predicting Diabetic Foot Osteomyelitis with Peripheral Artery Disease

Background: This study aims to assess the atherogenic index of plasma (AIP) diagnostic value in detecting diabetic foot osteomyelitis (DFO) among patients with diabetic foot ulcers (DFUs). Methods: A prospective cohort study was conducted on 80 patients with DFUs and suspected DFO between January 2022 and December 2023. The primary outcome measures included the diagnosis of DFO, determined by positive microbiological analysis results from bone samples and its correlation with the AIP. Receiver operating characteristic (ROC) curves were utilized to select the optimal diagnostic cut-off points for AIP and post hoc analysis was performed to evaluate the difference in the AIP for diagnosing DFO in patients with and without peripheral arterial disease (PAD). Results: The diagnostic potential for DFO in PAD patients of AIP-1 (Log TC/HDL) showed an AUC of 0.914 (p < 0.001 [0.832-0.996]), leading to a sensitivity of 83% and a specificity of 85%. By contrast, AIP-2 (Log TG/HDL) demonstrated a slightly lower AUC of 0.841 (p < 0.001 [0.716-0.967]), leading to a sensitivity of 76% and a specificity of 74%. Conclusions: The AIP tool, with its ideal blend of sensitivity and specificity, aids in predicting DFO effectively. Therefore, clinicians should consider using AIP for patients suffering from PAD and associated DFO.

Diagnosis of infection in the foot of patients with diabetes: A systematic review

BACKGROUND

Securing an early accurate diagnosis of diabetic foot infections and assessment of their severity are of paramount importance since these infections can cause great morbidity and potential mortality and present formidable challenges in surgical and antimicrobial treatment.

METHODS

In June 2022, we searched the literature using PubMed and EMBASE for published studies on the diagnosis of diabetic foot infection (DFI). On the basis of pre-determined criteria, we reviewed prospective controlled, as well as non-controlled, studies in English. We then developed evidence statements based on the included papers.

RESULTS

We selected a total of 64 papers that met our inclusion criteria. The certainty of the majority of the evidence statements was low because of the weak methodology of nearly all of the studies. The available data suggest that diagnosing diabetic foot infections on the basis of clinical signs and symptoms and classified according to the International Working Group of the Diabetic Foot/Infectious Diseases Society of America scheme correlates with the patient's likelihood of the need for hospitalisation, lower extremity amputation, and risk of death. Elevated levels of selected serum inflammatory markers such as erythrocyte sedimentation rate (ESR), C-reactive protein and procalcitonin are supportive, but not diagnostic, of soft tissue infection. Culturing tissue samples of soft tissues or bone, when care is taken to avoid contamination, provides more accurate microbiological information than culturing superficial (swab) samples. Although non-culture techniques, especially next-generation sequencing, are likely to identify more bacteria from tissue samples including bone than standard cultures, no studies have established a significant impact on the management of patients with DFIs. In patients with suspected diabetic foot osteomyelitis, the combination of a positive probe-to-bone test and elevated ESR supports this diagnosis. Plain X-ray remains the first-line imaging examination when there is suspicion of diabetic foot osteomyelitis (DFO), but advanced imaging methods including magnetic resonance imaging (MRI) and nuclear imaging when MRI is not feasible help in cases when either the diagnosis or the localisation of infection is uncertain. Intra-operative or non-per-wound percutaneous biopsy is the best method to accurately identify bone pathogens in case of a suspicion of a DFO. Bedside percutaneous biopsies are effective and safe and are an option to obtain bone culture data when conventional (i.e. surgical or radiological) procedures are not feasible.

CONCLUSIONS

The results of this systematic review of the diagnosis of diabetic foot infections provide some guidance for clinicians, but there is still a need for more prospective controlled studies of high quality.

The infected diabetic foot: Modulation of traditional biomarkers for osteomyelitis diagnosis in the setting of diabetic foot infection and renal impairment

The objective of this paper was to investigate erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP) in diagnosing pedal osteomyelitis (OM) in patients with and without diabetes, and with and without severe renal impairment (SRI). This was a retrospective cohort study of patients with moderate and severe foot infections. We evaluated three groups: Subjects without diabetes (NDM), subjects with diabetes and without severe renal insufficiency (DM-NSRI), and patients with diabetes and SRI (DM-SRI). SRI was defined as eGFR <30. We evaluated area under the curve (AUC), cutoff point, sensitivity and specificity to characterize the accuracy of ESR and CRP to diagnose OM. A total of 408 patients were included in the analysis. ROC analysis in the NDM group revealed the AUC for ESR was 0.62, with a cutoff value of 46 mm/h (sensitivity, 49.0%; specificity, 76.0%). DM-NSRI subjects showed the AUC for ESR was 0.70 with the cutoff value of 61 mm/h (sensitivity, 68.9%; specificity 61.8%). In DM-SRI, the AUC for ESR was 0.67, with a cutoff value of 119 mm/h (sensitivity, 46.4%; specificity, 82.40%). In the NDM group, the AUC for CRP was 0.55, with a cutoff value of 6.4 mg/dL (sensitivity, 31.3%; specificity, 84.0%). For DM-NSRI, the AUC for CRP was 0.70, with a cutoff value of 8 mg/dL (sensitivity, 49.2%; specificity, 80.6%). In DM-SRI, the AUC for CRP was 0.62, with a cutoff value of 7 mg/dL (sensitivity, 57.1%; specificity, 67.7%). While CRP demonstrated relatively consistent utility, ESR's diagnostic cutoff points diverged significantly. These results highlight the necessity of considering patient-specific factors when interpreting ESR results in the context of OM diagnosis.

Atherogenic index of plasma and coronary artery disease: A systematic review

Various studies suggest that the atherogenic index of plasma (AIP) is associated with the risk of coronary artery disease (CAD) in different clinical scenarios. This review aimed to synthesize evidence of the association between AIP values and CAD. A literature search was carried out on four databases, namely, PubMed, Scopus, Web of Science, and Ovid-Medline. A handsearch was performed on preprint repositories (MedRxiv and Research Square). The effect measurements were expressed as odds ratios (OR) with their corresponding 95% confidence intervals (CI). For the quantitative synthesis, we employed a random-effects model. We analyzed 14 articles (with 40,902 participants) from seven different countries. The quantitative analysis revealed that an increase in one unit of AIP was associated with higher odds of developing CAD (OR 2.11; 95% CI 1.65-2.69; P < 0.001; I ² = 98%). We conducted subgroup analyses of Chinese (OR 1.89; 95% CI 1.40-2.56; P < 0.001) and non-Chinese studies (OR 2.51; 95% CI 1.42-4.42; P < 0.001). The sensitivity analysis by risk of bias continued to demonstrate an association, and the heterogeneity remained unchanged (OR 1.75; 95% CI 1.33-2.31; P < 0.001; I ² = 98%). Higher AIP values were associated with higher odds of developing CAD.

Atherogenic index of plasma is an independent predictor of metabolic-associated fatty liver disease in patients with type 2 diabetes

Background

Metabolic-associated fatty liver disease (MAFLD), formerly known as non-alcoholic fatty liver disease, is the leading cause of liver disease that can ultimately lead to cirrhosis. Identifying a screening marker for early diagnosis of MAFLD in patients with type 2 diabetes (T2D) can reduce the risk of morbidity and mortality. This study investigated the association between the atherogenic index of plasma (AIP) and MAFLD in patients with T2D.

Method

A retrospective case–control study was conducted and medical records of patients with T2D were assessed. The baseline characteristics, anthropometric indices, laboratory measurements including liver functions tests, fasting blood sugar, HbA1C, lipid profile were documented.

Results

Out of 2547 patients with T2D, 824 (32.4%) had MAFLD. The multivariate logistic regression analysis showed a significant difference in female-to-male ratio (1.11 vs. 1.33, OR = 0.347, P-value < 0.001), ALT (42.5 ± 28.1 vs. 22.4 ± 11.1, OR = 1.057, P-value < 0.001), and AIP (0.6 ± 0.3 vs. 0.5 ± 0.3, OR = 5.057, P-value < 0.001) between MAFLD and non-MAFLD groups, respectively. According to the AIP quartile, the prevalence of MAFLD increased significantly in patients with higher AIP quartiles (P-value < 0.001). Also, we found a cut-off of 0.54 for AIP in predicting MAFLD in patients with T2D (sensitivity = 57.8%, specificity = 54.4%).

Conclusion

In this study, we found that AIP is a good and independent predictor for MAFLD in patients with T2D which could help physicians in early diagnosis and follow-up of patients with T2D.

The association between diabetes coexisting with low levels of high-density lipoprotein cholesterol and peritoneal dialysis-related peritonitis

BACKGROUND

Low levels of high-density lipoprotein cholesterol (HDL-C) and diabetes are common in patients undergoing peritoneal dialysis (PD). The aim of this study was to investigate the association between the coexistence of diabetes with a low level of HDL-C and the first episode of peritoneal dialysis-related peritonitis (PDRP) in patients with PD.

METHODS

We retrospectively investigated patients with PD from January 1, 2003, to May 31, 2020, in four PD centers. Patients with PD were divided into four groups: no comorbidities, low HDL-C only, diabetes only, and diabetes plus low HDL-C. The clinical and laboratory baseline data of the four groups were collected and compared. The association between diabetes coexisting with low HDL-C levels and the first episode of PDRP was analyzed by multivariate Cox regression analysis.

RESULTS

A total of 1013 patients with PD were included in our study. The mean age was 49.94 ± 14.32 years, and 597 (58.99%) patients were males. A total of 301 (29.7%) patients had their first episodes of PDRP, and low HDL-C levels coexisted with diabetes in 72 patients with PD. After adjusting for confounding factors, a low level of HDL-C coexisting with diabetes was significantly associated with the first episode of PDRP in our study (hazard ratio: 2.81, 95% CI 1.32 ~ 4.73, p = 0.005). The associations among HDL-C, diabetes and PDRP were consistent in the following subgroups: sex, age, and pre-existing CVD (all P interaction > 0.05).

CONCLUSIONS

Patients with both diabetes and low HDL-C levels were at higher risk for PDRP in patients with PD.

Lipoprotein Ratios: A Potential Biomarker for Clinical Diagnosis of Atherosclerosis in Type 1 Diabetic Patients With Foot Ulceration

Background Lipoprotein ratios are indicators of atherosclerosis and related diseases such as cardiovascular diseases (CVDs). Early and accurate diagnosis of atherosclerotic disease in patients with diabetic foot ulceration (DFU) is required urgently and remains fundamental to assess the risk of CVDs. This study aimed to determine whether lipoprotein ratios can predict atherosclerosis in type 1 diabetic patients with DFU. Methodology This was a cross-sectional study including 255 patients with confirmed type 1 diabetes with a male-to-female ratio of 1.19. Patients admitted to the hospital due to diabetes-related complications were divided into the following groups: patients without DFU (n = 153) and patients with DFU (n = 102). Clinical, biological, and pathophysiological features of patients were compared. Results Our study reported a distinct predominance of males (54.50%), with a mean age of 28.64 ± 10.92 years and duration of diabetes of 10.40 ± 9.25 years. The prevalence of DFU was 40.0%. The receiver operator characteristic curve was applied to define the best cut-off lipid ratios to detect atherosclerosis. Total cholesterol (TC)/high-density lipoprotein (HDL) ratio was a valid marker for atherosclerosis with a sensitivity of 86.3%, specificity of 71.4%, and diagnostic accuracy of 0.836%. The findings showed that the fourth quartiles (odds ratio [OR] = 83.02 [22.18-310.75]; p = <10^-3) of TC/HDL ratio was significantly higher in patients with DFU. Similarly, the last quartiles (fourth) of low-density lipoprotein (LDL)/HDL and triglyceride (TG)/HDL ratio were higher in DFU group (OR = 33.71 [12.04-94.38], p = <10^-3; OR = 9.60 [4.27-21.58], p = <10^-3; respectively). In the DFU group, conventional lipid profiles and lipid ratios were markedly higher in males compared to females patients (TG = 1.31 ± 0.69 g/L vs. 1.04 ± 0.84 g/L, p = 0.04; respectively; TC/HDL = 4.79 ± 1.04 vs. 4.22 ± 0.98, p = 0.03; respectively; LDL/HDL = 2.91 ± 1.13 vs. 2.17 ± 1.28, p = 0.01; respectively; TG/HDL = 3.65 ± 2.53 vs. 2.67 ± 1.94, p = 0.008; respectively). Conclusions Elevated atherogenic indices were significantly associated with the atherosclerotic load in patients with DFU, supporting the use of lipid ratios as a biomarker for the diagnosis of atherosclerosis disease in clinical practice in the future.