Serum LDL level as an indirect marker of erectile dysfunction in male CAD patients

ABSTRACT

Introduction:

Erectile dysfunction (ED) is a prevalent condition among male patients with coronary artery disease (CAD), often reflecting underlying vascular problems. Recent studies suggest that serum low-density lipoprotein (LDL) levels, a key factor in atherosclerosis, might serve as an indirect marker of ED in this population.

Aims & Objectives:

The aim of our study is to analyse correlation between serum LDL level and severity of erectile dysfunction. To assess the prevalence of erectile dysfunction in male CAD patients. To evaluate other potential risk factors contributing to erectile dysfunction in male CAD patients.

Method:

From September 2022 to August 2023, 240 CAD patients were analysed for organic ED with the help of IIEF-5 score, and their lipid profile (Cholesterol, Triglyceride, HDL, LDL) were compared.

Results:

Mean age in the study group is 47.61± 7.82 years. The overall prevalence of ED among MALE CAD patients was found out to be 73%, with Mean IIEF-5 score of 16.9 with SD 4.89. LDL cholesterol level had a positive correlation with Severity of ED (p value 4.88×10-16, r=-0.7052, r2=0.49). Mean LDL 95.83mg/dl with a standard deviation of 31.37. Serum cholesterol level had a positive correlation with Severity of ED (p value= 2.84×10-9). Mean Cholesterol level is 165.5mg/dl with a SD of 38.66.

Conclusion:

Treatment for hyperlipidaemia plays a crucial role in preventing ED, as evidenced by the impact of total cholesterol and LDL in particular on men’s erectile function. This highlights the need for a comprehensive approach to managing ED patients.

Introduction

Coronary artery disease (CAD) remains a leading cause of morbidity and mortality worldwide, characterized by the narrowing or blockage of coronary arteries due to atherosclerosis.[1] While its clinical manifestations, such as angina, myocardial infarction, and heart failure, are well recognized, there is growing awareness that CAD also shares a strong pathophysiological link with erectile dysfunction (ED)—a condition often underreported and underdiagnosed in male patients with cardiovascular risk factors.[2] Erectile dysfunction is inability to consistently get or sustain an erection strong enough for satisfying sexual performance is known as erectile dysfunction.[3] It is a multifactorial condition with aetiologies spanning psychological, neurological, hormonal, and vascular domains.[4] Importantly, these same mechanisms are central to the development and progression of atherosclerosis and CAD, suggesting that ED may serve as an early clinical manifestation of systemic vascular disease.[5]

In primary care, where comprehensive management of chronic conditions such as diabetes, hypertension, and dyslipidemia is central, the early detection and evaluation of ED may offer valuable insight into underlying cardiovascular risk. Studies show that ED often precedes overt coronary events by 2 to 5 years, highlighting its potential utility as a clinical red flag in cardiovascular risk stratification.[6]

The prevalence of ED has risen considerably over the decades, increasing with age and comorbidities. The Massachusetts Male Aging Study reported a prevalence of complete ED rising from 5% in men aged 40 to 15% in men aged 70.[7] Moreover, the incidence of ED is associated with several CAD risk factors, including elevated low-density lipoprotein (LDL) cholesterol, diabetes mellitus, hypertension, smoking, and obesity, all of which are routinely managed in the primary care setting.[8]

LDL-cholesterol plays a central role in endothelial dysfunction by promoting oxidative stress, decreasing nitric oxide (NO) bioavailability, and exacerbating vascular inflammation—all mechanisms implicated in both CAD and ED.[9,10,11] Notably, clinical studies have demonstrated that statins not only lower LDL-cholesterol but also improve endothelial function and erectile performance, underscoring the interconnectedness of cardiovascular and sexual health.[12]

Given the shared pathophysiology and overlapping risk factors, evaluating erectile function in men with CAD offers an opportunity for early intervention, holistic care, and improved quality of life. Primary care physicians are uniquely positioned to identify and address ED during routine cardiovascular risk assessment, thereby facilitating earlier detection of vascular dysfunction and encouraging patient-centered discussions on sexual health, often overlooked in busy clinical settings.

This study aims to explore the correlation between serum LDL-cholesterol levels and the severity of erectile dysfunction in male patients with CAD. Additionally, it assesses the overall prevalence of ED in this population and examines other potential contributing risk factors.

Material and Method

Study design and setting

This cross-sectional, observational study was conducted in the Department of General Medicine at Shyam Shah Medical College, Rewa, Madhya Pradesh, over a period of 12 months from September 2022 to August 2023. Ethical clearance was obtained from the Institutional Ethics Committee before initiation of the study.

Study population

A total of 240 male patients diagnosed with coronary artery disease (CAD) were enrolled based on predefined eligibility criteria. All participants were between 18 and 60 years of age and were sexually active at the time of recruitment.

Inclusion criteria

1. Male patients aged 18–60 years.

2. Sexually active individuals.

3. Diagnosed cases of CAD confirmed by any one of the following:

   • Electrocardiography (ECG)

   • 2D Echocardiography (2D-ECHO)

   • Treadmill Test (TMT)

   • Coronary Angiography

   • Patients already receiving treatment for CAD.

Exclusion criteria

1. Known cases of Diabetes Mellitus.

2. Patients currently on treatment for erectile dysfunction.

3. History or clinical diagnosis of hypogonadism or hypopituitarism.

4. Patients taking medications known to interfere with sex hormone levels, such as:

   • Androgens, estrogens, progesterone

   • Thiazides, spironolactone, cimetidine.

Data collection and assessment tools

Eligible patients underwent a structured clinical evaluation, including detailed history-taking with a focus on sexual health and cardiovascular risk factors. Erectile function was assessed using the International Index of Erectile Function-5 (IIEF-5) questionnaire, a self-reported tool consisting of five items that evaluate the severity of erectile dysfunction over the preceding six months.

The international index of erectile function (IIEF-5) questionnaire[13]

Over the past 6 months

1. How do you rate your confidence that you could get and keep an erection?

   Very low 1, Low 2, Moderate 3, High 4, Very high 5.

2. When you had erections with sexual stimulation, how often were your erections hard enough for penetration?

   Almost never/never 1, A few times (much less than half the time) 2, Sometimes (about half the time) 3, Most times (much more than half the time) 4, Almost always/always 5.

3. During sexual intercourse, how often were you able to maintain your erection after you had penetrated (entered) your partner?

   Almost never/never 1, A few times (much less than half the time) 2, Sometimes (about half the time) 3, Most times (much more than half the time) 4, Almost always/always 5.

4. During sexual intercourse, how difficult was it to maintain your erection until completion of intercourse?

   Extremely difficult 1, Very difficult 2, Difficult 3, Slightly difficult 4, Not difficult 5.

5. When you attempted sexual intercourse, how often was it satisfactory for you? Almost never/never 1, A few times (much less than half the time) 2, Sometimes (about half the time) 3, Most times (much more than half the time) 4, Almost always/always 5.

Based on the IIEF-5 score, erectile dysfunction was categorized as 22–25: No ED, 17–21: Mild ED, 12–16: Mild to moderate ED, 8–11: Moderate ED, 5–7: Severe ED

Laboratory Investigations: All participants underwent fasting venous blood sampling to measure serum lipid parameters consistent including total cholesterol, triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL) by using enzymatic spectrophotometric methods.

LDL levels were categorized and interpreted by standard clinical cut-offs:

• Optimal: <100 mg/dL

• Near-optimal: 100–129 mg/dL

• Borderline high: 130–159 mg/dL

• High: 160–189 mg/dL

• Very high: ≥190 mg/dL

Statistical analysis

Data were recorded using a structured proforma and managed in Microsoft Excel. Quantitative variables were expressed as mean ± standard deviation. Differences between groups based on erectile dysfunction severity were analyzed using one-way analysis of variance (ANOVA) and the independent sample t-test, as appropriate. A P value of < 0.05 was considered statistically significant.

Results

The study group included 240 patients, with the majority (47.0%) in the 50–59 years age group, followed by 40–49 years (40.8%), 30–39 years (9.16%), and 18–29 years (2.91%). The mean age is 47.61 ± 7.82 years. Hypertension (HTN) is the most common comorbidity, affecting 32.91% of patients, while coronary artery disease (CAD) affects 2.5%, and Cerebrovascular Accident (CVA) and Chronic Obstructive Pulmonary Disease (COPD) affect 1.66% and 1.25%, respectively. Hypothyroidism is the least common condition, was present in only 0.41% of patients. Notably, 61.25% of patients had no comorbid conditions. The mean LDL cholesterol level was 95.83 mg/dl (SD = 31.37), with most patients having LDL-C levels below 100 mg/dl.

Table 1. Illustrates the relationship between LDL-C levels and erectile dysfunction (ED) severity, as measured by the IIEF-5 scores. Individuals with LDL-C levels <100 mg/dl (n = 129) had the highest mean IIEF-5 score (18.98), with 37.2% reporting no ED and only 2.3% reporting severe ED. As LDL-C levels increased, the mean IIEF-5 score decreased, and the prevalence of moderate to severe ED rose. In the 100–129 mg/dl group (n = 84), the mean score dropped to 15.35, with 62% reporting mild to moderate ED. In the 130–159 mg/dl group (n = 20), the mean score was 11.65, with 65% reporting moderate or severe ED. The highest LDL-C group (≥160 mg/dl, n = 7) had a mean score of 11.85, with 42.85% experiencing severe ED. Statistical analysis using one-way ANOVA (F-statistic = 28.543, P = 4.8 × 10⁻¹⁶) confirms a significant association between higher LDL-C levels and more severe ED.

Table 1.

Correlation between LDL level and IIEF-5 score

LDL-C Levels (Mg/dl)	IIEF-5 score grading					IEF-5 score (25) (Mean±SD)
	No ED (22−25) n=65	Mild ED (17–21) n=65	Mild-to-Moderate ED (12–16) n=76	Moderate ED (8–11) n=21	Severe ED (5–7) n=13
<100 (129)	48 (37.20%)	52 (40.31%)	21 (16.29%)	5 (3.87%)	3 (2.32%)	18.98±3.8
100–129 (n=84)	13 (15.47%)	10 (11.9%)	52 (62%)	5 (5.95%)	04 (4.76%)	15.35±4.3
130159 (n=20)	03 (15%)	02 (10%)	02 (10%)	10 (50%)	03 (15%)	11.65±5.2
≥160 (n=07)	01 (14.28%)	01 (14.28%)	01 (14.28%)	01 (14.28%)	03 (42.85%)	11.85±5.9
F-statistic	28.543			P		4.88×10-16

X axis – IIEF -5 score values, Y axis – LDL-C values.

The value of the correlation coefficient (r) is − 0.7052.

This is a moderate negative correlation, which means there is a tendency for high X variable scores to go with low Y variable scores (and vice versa).

The value of R², the coefficient of determination, is 0.4973.

The analysis of Table 2 reveals that age (P = 0.044), BMI (P = 0.031), waist–hip ratio (P = 0.002), total cholesterol (P < 0.05), LDL-C (P < 0.05), and the LDL-C/HDL-C ratio (P < 0.05) are significantly correlated with the severity of erectile dysfunction (ED), suggesting that older age, higher BMI, larger waist-hip ratios, and elevated cholesterol and LDL-C levels are associated with more severe ED. In contrast, parameters such as SBP (P = 0.24), DBP (P = 0.43), triglycerides (P = 0.32), HDL-C (P = 0.07), VLDL-C (P = 0.93), AIP (P = 0.09), and serum creatinine (P = 0.87) do not show significant correlations with ED severity.

Table 2.

Parameters with their mean value correlated with IIEF-5 score

Parameters Mean value	IIEF-5 Score					P
	No ed (22–25)	Mild ed (17–21)	Mild-to-moderate (22–25)	Moderate (12–16)	Severe (5–7)
Age (Years)	46.6	47.32	47.70	48.38	51.84	0.04
BMI (kg/m2)	24.02	23.74	24.50	24.62	24.67	0.03
Waist-Hip ratio	0.94	0.93	0.94	0.98	1.01	<0.05
SBP (mmhg)	128.5	125	128.9	131.04	133	0.24
DBP (mmhg)	78.18	78.83	76	78.09	82	0.43
Cholesterol (mg/dl)	140	154.52	179	201	206.6	<0.05
TGs (mg/dl)	158	148.67	157.39	157.76	164.6	0.32
HDL-C (mg/dl)	39.17	39.65	43.05	41.09	39.16	0.07
LDL-C (mg/dl)	69.52	84.78	112	127	134.16	<0.05
VLDL-C (mg/dl)	31.62	29.70	30.22	30.8	33.09	0.93
LDL-C/HDL-C ratio	1.84	2.23	2.67	3.152	3.533	<0.05
AIP=Log(TGs/HDL-C)	0.56	0.53	0.534	0.57	0.62	0.08
S.Creatinine (mg/dl)	0.95	1.11	1.057	0.87	0.92	0.87

Discussion

This study provides valuable insights into the relationship between coronary artery disease (CAD) and erectile dysfunction (ED), with a particular focus on serum LDL-cholesterol as an indirect marker of ED severity in male CAD patients. Among 240 participants, the overall prevalence of ED was 73%. Specifically, 27.05% had no ED, 27.05% had mild ED, 31.66% had mild to moderate ED, 8.75% had moderate ED, and 5.41% had severe ED. The mean IIEF-5 score was 16.9 (SD = 4.89), indicating mild-to-moderate ED on average, though the variation in scores reflects a wide spectrum of erectile function among CAD patients.

Our findings are comparable to those of Islam Mohamed Abd Elsamie et al.[14] (2024), who used the IIEF-5 questionnaire to classify ED severity. In their cohort, 38.5% of patients had mild ED, 23.1% had mild-to-moderate ED, 21.1% had moderate ED, and 13.5% had severe ED.

A central aim of our study was to evaluate the association between LDL-cholesterol levels and ED severity. Among patients with LDL-C levels <100 mg/dL (n = 129), the mean IIEF-5 score was 18.98 ± 3.8, with 37.2% reporting no ED and only 2.3% reporting severe ED. In contrast, patients with LDL-C levels of 100–129 mg/dL (n = 84) had a lower mean score of 15.35 ± 4.3, and 4.8% reported severe ED. Those in the 130–159 mg/dL group (n = 20) had a mean score of 11.65 ± 5.2, with 15% reporting severe ED. Strikingly, in the ≥160 mg/dL group (n = 7), the mean score was 11.85 ± 5.9, and 42.9% had severe ED. ANOVA analysis revealed a statistically significant difference in ED severity across these LDL groups (F = 28.543, P < 0.05). A strong negative correlation between LDL-C levels and IIEF-5 scores (r = −0.70, r² =0.49, P < 0.0001) was observed, indicating that higher LDL levels are closely associated with more severe ED [Graph 1].

Graph 1.

Correlation between LDL level and IIEF-5 score

These results are supported by earlier studies. Ponholzer et al.[15] (2006) found that men with moderate to severe ED (IIEF-5 score 5–11) had 11.8% higher LDL levels (P = 0.02) than those with no or mild ED (score 12–25). Similarly, Nikoobakht et al.[16] (2005) reported high plasma LDL (≥160 mg/dL) in 53% of ED patients versus 17% of controls (P = 0.02), especially in individuals over age 40 (42% vs. 13%, P = 0.04). These findings reinforce the vascular etiology of ED and the central role of dyslipidemia in both penile and coronary arterial disease.

Our study also explored correlations between IIEF-5 scores and various clinical and laboratory parameters. Significant associations were found with age (P = 0.04), BMI (P = 0.03), waist–hip ratio (P < 0.05), total cholesterol (P < 0.05), LDL-C (P < 0.05), and the LDL-C/HDL-C ratio (P < 0.05), suggesting that older age, higher adiposity, and elevated cholesterol parameters are linked to more severe ED. Conversely, no significant associations were observed with systolic or diastolic blood pressure, triglycerides, HDL-C, VLDL-C, AIP, or serum creatinine.

Again, these findings align with the work of Ponholzer et al. (2006), who found that men with moderate to severe ED had 8.3% higher total cholesterol (P = 0.04) and a 2.6-fold greater risk of ED if LDL exceeded 160 mg/dL. However, their study did not find significant associations between ED and factors like blood pressure, fasting glucose, nicotine use, BMI, or waist–hip ratio.

This study is especially relevant to primary care physicians (PCPs) and family medicine practitioners, who often serve as the first point of contact for patients with cardiovascular risk factors or sexual health concerns. ED is frequently underreported in routine clinical practice, yet it can be an early clinical manifestation of endothelial dysfunction and a harbinger of underlying atherosclerotic disease. By integrating simple, non-invasive tools such as the IIEF-5 questionnaire along with lipid profile evaluation, PCPs can identify patients who may be at risk for both ED and more severe CAD. This offers an opportunity for earlier intervention and more comprehensive risk management.

For family physicians, these results underscore the importance of addressing sexual health as part of a routine cardiovascular risk assessment. Men presenting with ED, particularly those with elevated LDL levels, should be screened for asymptomatic CAD. Conversely, CAD patients, especially younger males, should be proactively questioned about sexual function as part of holistic care. Addressing ED in these populations not only improves quality of life but also may reveal opportunities for earlier cardiovascular intervention.

Limitations

While the study presents compelling findings, it is not without limitations:

• The sample size was limited and derived from a single tertiary care center.

• The lack of a control group limits broader generalizability.

• More comprehensive evaluations, such as serum testosterone levels or penile Doppler studies, could have provided deeper insights into the etiology of ED in this population.

Conclusion

CAD and ED share a common vascular etiology, with LDL-cholesterol emerging as a key biomarker bridging both conditions. Our study establishes a significant correlation between elevated LDL levels and the severity of ED in male CAD patients. For primary care physicians and family doctors, incorporating LDL-C screening and ED assessment can enhance cardiovascular risk stratification and guide early preventive strategies. This dual-benefit approach not only addresses sexual health, a critical but often neglected aspect of men’s health, but also aids in the timely identification and management of subclinical vascular disease.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.