The relationship between erectile dysfunction and the Atherogenic Index of Plasma

The role of lipidic balance on erectile dysfunction in prostate cancer patients undergoing robotic surgery

OBJECTIVE

New indices of dyslipidemia, such as the Atherogenic Index of Plasma (AIP) or Castelli Risk Index I and II (CR-I/II), have been tested to predict erectile dysfunction (ED). The aim of this study was to assess the role of these lipidic scores in predicting severe ED and erectile function (EF) worsening in patients who underwent robot-assisted radical prostatectomy (RARP).

METHODS

Data from 1249 prostate cancer patients who underwent RARP at our single tertiary academic referral center from September 2021 to April 2023 were reviewed. RARP patients with a complete lipid panel were included in the final analysis. Two independent multivariable logistic regression models (LRMs) were fitted to identify predictors of ED severity and worsening in RARP patients.

RESULTS

Among the 357 RARP patients, the median age was 70 (interquartile range [IQR]: 65-74), and the median BMI was 28.4 (IQR: 26-30.4). According to the preoperative IIEF5, 115 (32.2%), 86 (24.5%), 26 (7.3%), and 40 (11.2%) were mild, mild-moderate, moderate, and severe ED patients, respectively. After multivariable LRMs predicting severe ED, only the nerve-sparing (NS) approach (odds ratio [OR]: 0.09) as well as the preoperative IIEF5 score (OR: 0.32) were independent predictors (p < 0.001). After LRMs predicting EF worsening, only preoperative IIEF5 was an independent predictor (OR: 1.42, p < 0.001).

CONCLUSION

The power of novel lipidic scores in predicting severe ED and EF worsening in RARP patients was low, and they should not be routinely applied as a screening method in this patient subgroup. Only preoperative IIEF5 and nerve-sparing approaches are relevant in EF prediction after RARP.

Association between cardiometabolic index and erectile dysfunction among US adults: a cross-sectional analysis of the National Health and Nutrition Examination Survey 2001-2004

The aim of this study was to assess the association between a new metabolic index, the cardiometabolic index (CMI) and erectile dysfunction (ED). The data for this study relied on the National Health and Nutrition Examination Survey (NHANES), a cross-sectional database, between 2001 and 2004. The CMI was calculated as the following formula: Triglyceride (TG) (mmol/L)/ High density lipid-cholesterol (HDL-C) (mmol/L) ×waist-height ratio (WHtR). The multivariate logistic regression analyses were conducted to assess the association between CMI and ED, supplemented by subgroup analysis and dose-response curves. Finally, a total of 1367 adult male participants were identified, and the mean CMI was 0.83 ± 0.02. Multivariate logistic regression analysis showed that in model 2 controlling for all potential confounders, CMI was significantly associated with ED (OR = 1.49, 95% CI: 1.09, 2.04) (p = 0.017). Subsequently, we convert the CMI from a continuous variable to a categorical variable (Tertiles). The results showed that male participants in CMI Tertile 3 group had a higher risk of ED than those in Tertile 1 group in model 2 (OR = 2.07, 95% CI: 1.12, 3.83, P = 0.024). The subgroup analysis of model 2 demonstrated that CMI was significantly associate with ED in participants aged ≥50 y (OR = 2.31, 95% CI: 1.35, 3.95, P = 0.005), body mass index (BMI) > 30 kg/m2 (OR = 1.78, 95% CI: 1.10, 2.90, P = 0.023), with hypertension (OR = 1.89, 95% CI: 1.63, 3.45, P = 0.020), with diabetes mellitus (OR = 1.67, 95% CI: 1.13, 2.47, P = 0.015), with cardiovascular disease (CVD) (OR = 1.54, 95% CI: 1.12, 2.10, P = 0.011) and smoking (OR = 2.07, 95% CI: 1.26, 3.39, P = 0.007). This study demonstrates a strong association between CMI and ED and an increased risk of ED with higher CMI levels. More prospective studies with large samples and good designs are needed to validate our results in the future.

Association between atherogenic indexes and erectile dysfunction: a cross-sectional analysis of the National Health and Nutrition Examination Survey 2001-2004

PURPOSE

Elevated blood lipids are considered a risk factor for atherosclerosis, which can lead to erectile dysfunction. This study aimed to explore the relationship between the atherogenic index of plasma (AIP), atherogenic coefficient (AC), Castelli's risk index-I (CRI-I), Castelli's risk index-II (CRI-II), and erectile dysfunction.

METHODS

Based on the National Health and Nutrition Examination Survey (NHANES) data from 2001-2004, multivariable-adjusted logistic regression models were used to evaluate the association between AIP, AC, CRI-I, and CRI-II with ED. Smooth curve fitting was employed to assess the linear association.

RESULTS

A total of 1806 male participants with complete data were enrolled in the study. In Model 1, those in the highest tertile of AIP had a 49% increased risk of ED compared to the lowest tertile (OR 1.49; 95% CI 1.15-1.91 p = 0.0021). After adjusting for the variables of age, race, education, body mass index, and poverty income ratio (PIR), significant positive correlations were found between ED and AIP, with each 1-unit increase in AIP associated with a 65% increase in the risk of developing ED (OR 1.65; 95% CI 1.03-2.64 p = 0.0361).

CONCLUSIONS

AIP is positively associated with the development of ED in US adults. More prospective cohort studies are needed to confirm the link between AIP and ED.

The Association between the Gut Microbiota and Erectile Dysfunction

PURPOSE

Explore the causal relationship between the gut microbiota and erectile dysfunction (ED) at phylum, class, order, family, and genus levels, and identify specific pathogenic bacteria that may be associated with the onset and progression of ED.

MATERIALS AND METHODS

The genetic variation data of 196 human gut microbiota incorporated in our study came from the human gut microbiome Genome Wide Association Studies (GWAS) dataset released by the MiBioGen Consortium. The GWAS statistics for ED were extracted from one study by Bovijn et al., which included 223,805 participants of European ancestry, of whom 6,175 were diagnosed with ED. Subsequently, Mendelian randomization (MR) analysis was carried out to explore whether a causal relationship exists between the gut microbiota and ED. Additionally, bidirectional MR analysis was performed to examine the directionality of the causal relationship.

RESULTS

Through MR analysis, we found that family Lachnospiraceae (odds ratio [OR]: 1.27, 95% confidence interval [CI]: 1.05-1.52, p=0.01) and its subclass genus LachnospiraceaeNC2004 group (OR: 1.17, 95% CI: 1.01-1.37, p=0.04) are associated with a higher risk of ED. In addition, genus Oscillibacter (OR: 1.17, 95% CI: 1.02-1.35, p=0.03), genus Senegalimassilia (OR: 1.32, 95% CI: 1.06-1.64, p=0.01) and genus Tyzzerella3 (OR: 1.14, 95% CI: 1.02-1.27, p=0.02) also increase the risk of ED. In contrast, the inverse variance weighted estimate of genus RuminococcaceaeUCG013 (OR: 0.77, 95% CI: 0.61-0.96, p=0.02) suggests that it has a protective effect against the occurrence of ED.

CONCLUSIONS

This study preliminarily identified 6 bacterial taxa that may have a causal relationship with ED, including family Lachnospiraceae, genus Lachnospiraceae NC2004 group, Oscillibacter, Senegalimassilia, Tyzzerella 3 and Ruminococcaceae UCG013. These identified important bacterial taxa may serve as candidates for microbiome intervention in future ED clinical trials.

Can atherogenic indices and the triglyceride-glucose index be used to predict erectile dysfunction?

Background

Atherosclerosis and insulin resistance play an important role in the development of erectile dysfunction (ED), and few studies have comprehensively evaluated more specific indicators like atherogenic indices and the triglyceride-glucose (TyG) index in the assessment of ED.

Aim

This study aimed to reveal the role of atherogenic indices (atherogenic index of plasma [AIP], Castelli risk index-1/2 [CRI-1/2], and atherogenic coefficient [AC]) based on plasma lipid ratios, which have been used as more sensitive indicators of atherosclerosis in recent years, and the TyG index, a practical indicator of insulin resistance, in predicting vasculogenic ED.

Methods

The study included a total of 199 patients who met the inclusion criteria and a total of 51 control subjects without ED complaints according to the International Index of Erectile Function (IIEF-5) scores (>21) between May 2021 and October 2022. For all participants, the demographic and biochemical parameters were evaluated, and atherogenic indices, namely CRI-1 (total cholesterol/high-density lipoprotein [HDL]), CRI-2 (LDL/HDL) AIP [log10(triglycerides/HDL)], and AC (non-HDL/HDL), as well as the TyG index [Ln {fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2}] were calculated.

Outcomes

The TyG index, which is an indicator of insulin resistance, and atherogenic indices such as CRI-1, AIP, and AC were significantly associated with ED, and especially AIP and the TyG index seem to be more important in the evaluation of ED.

Results

According to the univariate analysis, the patient group had significantly higher CRI-1 (5.3 ± 1.4 vs 4.7 ± 1.3; P = .005), AIP (0.31 ± 0.26 vs 0.13 ± 0.2; P < .001), AC (4.1 ± 1.4 vs 3.70 ± 1.2; P = .026), and TyG (9.16 ± 0.71 vs 8.77 ± 0.52; P < .001) values compared with the control group. In the correlation analysis, a significant negative correlation was found between the AIP and TyG index and the IIEF-5 scores (r2 = 0.120, P < .001 between AIP and IIEF-5; r2 = 0.091, P < .001 between TyG index and IIEF-5). The multivariate analysis revealed AIP and the TyG index as independent predictive factors for ED.

Clinical Implications

The use of atherogenic indices and TyG index in daily urology practice can help physicians in the diagnosis and follow-up of ED.

Strengths and Limitations

The lack of sex hormone-binding globulin and free testosterone levels represents a limitation of our study. Another limitation is that the severity of ED was determined using the IIEF-5 scores, rather than a more objective method, such as penile artery ultrasound.

Conclusion

Atherogenic indices and the TyG index can be used as inexpensive and practical markers to predict the severity of arteriogenic ED.

The correlation between atherogenic indexes and erectile dysfunction

Aside from the ordinary plasma lipid level measurements, the ratios based on individual plasma lipid levels such as atherogenic index of plasma (AIP), Castelli's risk index 1/2 (CRI-1/2), and atherogenic coefficient (AC) are the novel parameters to evaluate the patients with a high risk of CVD. In this study, we aim to evaluate the relationship between AIP, AC, and CRI-1/2 with increased risk of ED. Between April 2018 and February 2019, 253 patients, who were diagnosed as a vasculogenic ED in our clinic, were enrolled in the study. While the first group (n = 134) consisted of patients with moderate and mild ED (IIEF-EF: 17-30), the second group (n = 119) consisted of patients with severe ED. In addition to the mean values of lipid parameters; CRI-1 (total cholesterol/HDL), CRI-2 (LDL/HDL) AIP (log10(triglycerides/HDL), and AC (non-HDL/HDL) were calculated. The mean age was 44.02 ± 10.41 (24-70), and the mean BMI was 27.80 ± 4.12 (18.52 ± 41.97). However, CRI-1 and AIP values were found to be higher in the severe ED group compared to the mild ED group (CRI-1: 4.50 ± 1.47, 4.88 ± 1.30; p = .039; AIP: 0.489 ± 0.315, 0.617 ± 0.283; p = .007). Our results demonstrated that CR-1 and AIP have a positive correlation with the severity of ED. Moreover, we can suggest that patients with higher CR-1 and AIP values are likely to have more severe ED in the future.