P–089 Paternal age affects the performance of EAU guidelines for genetic testing in infertile men: implications for candidate selection

Study question

We aimed at challenge EAU Guidelines for genetic testing performance in infertile men according to normal vs. advanced paternal age (APA).

Summary answer

EAU Guidelines perform better in karyotype analysis (KA) and Y-chromosome microdeletions (YCM) investigation in men above 35 years of age.

What is known already

EAU Guidelines for genetic testing in infertile men recommend specific threshold for candidate selection for both KA (<10 million spermatozoa/ml) and YCM (<5 million spermatozoa/ml). However, paternal age is not taken into account for candidate selection in this setting.

Study design, size, duration

Data from 2188 infertile men (according to WHO definition) consecutively evaluated at a single academic centre were analysed.

Participants/materials, setting, methods

Demographic, clinical and laboratory data were analysed. Semen analyses were based on 2010 WHO criteria. Advanced age was defined as above 35. All men underwent KA and YCM testing. EAU Guidelines were validated in our cohort and according to APA. Specificity, sensitivity, and AUC were estimated for all scenarios. A Wald-type test compared AUC according to APA for KA and YCM. Decision curve analysis (DCA) estimated the benefit of using EAU Guidelines according to APA.

Main results and the role of chance

Median (IQR) paternal age was 37 (34–41) years. Advanced paternal age was found in 1306 (60%) of included men. Prevalence of KA and YCM was 4% (48 men) and 1% (13 men), respectively. EAU Guidelines sensitivity, specificity and AUC in the overall population were 85%, 47% and 66% for KA, whereas they were 100%, 57% and 80% for YCM. When stratifying according to APA, EAU Guidelines performed better in men over 35 both in terms of KA and YCM detection. Specifically, AUC for KA detection in men with APA was 70% vs. 63% in younger men (p = 0.04). AUC for YCM detection in men with APA was 82% vs. 79% in younger men (p = 0.03). DCA confirmed higher net benefit in using EAU Guidelines in old vs. young men for the detection of both KA and YCM.

Limitations, reasons for caution

It is a retrospective analysis at a single, tertiary-referral academic centre, thus raising the possibility of selection biases.

Wider implications of the findings: EAU Guidelines for genetic testing in infertile men perform differentially according to APA. KA and YCM are better detected in older men, likely due to a wider pool of confounding etiological factors in young men. These results suggest the implementation of more accurate predictive models in younger men.

Trial registration number

Not applicable

O-151 Detailed characterization of infertile men with idiopathic versus unexplained infertility: a single-center experience

Study question

We aimed to investigate the rate of and the clinical characteristics of men with idiopathic versus unexplained infertility from a cohort of white-European men.

Summary answer

Approximately 20% and 5% of men evaluated for primary couple’s infertility depicted characteristics suggestive for idiopathic and unexplained infertility, respectively.

What is known already

Male factor infertility (MFI) can be associated with clinical, hormonal and genetic diseases, but MFI is idiopathic in almost 30% of cases.

Study design, size, duration

Data from 3098 infertile men (according to WHO definition) consecutively evaluated between 2003-2020 at a single academic centre were analysed and compared with those of 103 fertile controls. Health-significant comorbidities were scored with the Charlson Comorbidity Index (CCI). Idiopathic infertility was defined for pathological semen analysis but normal physical examination and endocrine, genetic and biochemical laboratory testing. Unexplained infertility is defined as infertility of unknown origin with normal sperm parameters.

Participants/materials, setting, methods

Testicular volume (TV) was assessed with a Prader’s orchidometer. Serum hormones and sperm DNA fragmentation index (SDF) were measured in every patient. Vitamin D3 (VitD) deficiency was considered for vitD levels <20 ng/mL. Semen analyses were based on the 2010 WHO reference criteria. Health-significant comorbidities were scored with the Charlson Comorbidity Index (CCI).

Main results and the role of chance

Overall, 570 (18.5%) and 154 (5.0%) patients depicted criteria suggestive for either idiopathic or unexplained primary infertility, respectively. Groups were similar in terms of age, BMI, CCI, recreational habits, circulating serum hormones and SDF. Testicular volume was lower in men with idiopathic vs. unexplained infertility [median (IQR) 20 (15-25) vs. 20 (17-25); p < 0.001]; more idiopathic than unexplained infertile men depicted TV < 15ml (23.4% vs. 12%; p < 0.01). Similarly, vitD levels were lower [22 (17-28) vs. 27 (21-42) ng/mL; p < 0.001] in idiopathic vs. unexplained infertile men, with a higher rate of pathologic VitD levels in the same group (42.1% vs. 10%; p = 0.04). When compared to fertile controls, groups were similar in terms of age, BMI, CCI and serum hormones values. TV was larger in fertile controls than idiopathic and unexplained infertile men (all p < 0.01). At multivariable logistic regression analysis only vitD deficiency (OR 8.1, p = 0.03) was found to be associated with idiopathic infertility after accounting for age, BMI, testosterone values and TV. 

Limitations, reasons for caution

The small number of fertile controls may raise the possibility of biases.

Wider implications of the findings

Idiopathic and unexplained infertility were identified in approximately 20% and 5% of men evaluated, respectively. Idiopathic infertile men showed lower TV and lower vitD values compared to men with unexplained infertility. Future studies are needed to develop a more tailored management to these difficult MFI cases.

Trial registration number

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P–108 Which infertile men with normal semen analysis deserve a second semen analysis in the real-life setting?

Study question

Guidelines suggest that one semen analysis is sufficient during the diagnostic work-up of an infertile man in the case of normality as for WHO criteria.

Summary answer

We investigated the rate and the clinical features of men with abnormal sperm parameters at a second test, after a normal first semen analysis.

What is known already

A second test is recommended when the first semen analysis depicted abnormal sperm parameters.

Study design, size, duration

Complete demographic, clinical and laboratory data from 1358 consecutive primary infertile men (infertility as for WHO definition) were analysed. Health-significant comorbidities were scored with the Charlson Comorbidity Index (CCI). Serum hormones were measured in every patient. Patients underwent two consecutive semen analyses at the same laboratory, which followed 2010 WHO reference criteria.

Participants/materials, setting, methods

Descriptive statistics and logistic regression models tested the association between clinical variables and semen parameters. Receiver operative characteristic (ROC) curves were used to assess the relationship between clinical variables and to create a composite risk score for pathological sperm parameters at a second test.

Main results and the role of chance

At first analysis, 212 (15.6%) infertile men had normal semen parameters. Of 212, 87 (41.0%) had a second normal semen analysis, while 80 (37.7%), 35 (16.5%) and 10 (4.7%) men showed 1, 2 and 3 pathological sperm parameters at second test. Men with a pathological second semen analysis had higher CCI scores (p < 0.001), smaller testicular volume (p < 0.001) and higher FSH values (p < 0.01) than those with normal second samples. Overall, despite being within normal ranges, sperm concentration was lower [34 (23–57) vs. 62 (35–94); p < 0.01] in men with an abnormal second sample compared to those with confirmed normality. At multivariable logistic regression analysis, smaller testicular volume (OR 0.9, p = 0.03), FSH (OR 1.2, p < 0.01), and lower sperm concentration (OR 0.9, p < 0.01) were associated with pathological second semen analyses, after accounting for age and CCI. ROC curves showed that testicular volume <15 ml, FSH values >6 mUI/ml and sperm concentration <40 mil/ml had good predictive ability for pathologic second sperm parameters (all AUC >0.8). Considering 1-point for each of the previous variables, the chances of a pathological second analysis increased from 38.8% to 74.6%, 77.3% and 100% among patients with risk scores of 0, 1, 2 and 3, respectively (p < 0.001).

Limitations, reasons for caution

It is a retrospective analysis at a single, tertiary-referral academic centre, thus raising the possibility of selection biases. In spite of this, all patients have been consistently analysed over time with a rigorous follow-up, thus limiting potential heterogeneity in terms of data reporting.

Wider implications of the findings: Approximately 60% of infertile men with a normal semen analysis depicted a pathological second test. Smaller testicles, higher FSH, lower sperm concentrations were independently associated with a pathologic second test. These features could be useful to identify those infertile men with a normal semen analysis who deserve a second test.

Trial registration number

Not applicable

P–094 Kidney function impairment in primary infertile men

Study question

We investigated the prevalence of kidney function impairment in a homogeneous cohort of white-European primary infertile men.

Summary answer

Mild kidney function impairment characteristics were found in 9% of asymptomatic and unaware patients presenting for primary infertility investigation.

What is known already

Infertile men have shown a worse overall health status compared to the fertile counterpart. We investigated the prevalence of kidney function impairment in a homogeneous cohort of white-European primary infertile men.

Study design, size, duration

In this corss-sectional study, complete clinical and laboratories data from a cohort of 557 consecutive men aged >18 years, presenting for primary infertility investigation were analyzed.

Participants/materials, setting, methods

Comorbidities (as scored with the Charlson Comorbidity Index (CCI)) were collected in each patient. Primary outcome was the presence of functional impairment of the kidney (defined as an estimated glomerular filtration rates <90 ml/min/1.73m², according to the Kidney Outcomes Quality Initiative). The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) function was used for eGFR calculation. Logistic regression analyses tested the association between kidney function impairment and clinical and semen features.

Main results and the role of chance

Of 557, 51 (9.3%) patients depicted at least a mild loss of kidney function (eGFR<90 ml/min /1.73m²). Median [interquartile (IQR)] age was 38 (35–42) years for normal kidney function group vs. 41 (36–46.5) years for those with impaired renal function (p < 0.001). Those with impaired renal function had also a higher BMI [26.1 (24.4–27.8) vs. 24.9 (23.2–26.8); p = 0.002] and higher numbers of comorbidities [CCI≥ 1 in 11 (21.5%) vs. 40 (7.9%) patients (p < 0.001)]. Of note, they had more frequently history of hypertension [10 (19.6%) vs. 31 (6.1%), p = 0.001]. Groups did not differ in terms of hormonal and semen features. At logistic regression analysis, older age and CCI≥1 were associated with a higher risk of impaired eGFR (OR 1.06; 95%CI 1.01–1.11; p = 0.016 and OR 2.41; 95%CI 1.06–5.15; p = 0.028, respectively)(table). No association was found between sperm parameters and eGFR impairment (all p > 0.05), after accounting for age, CCI, BMI, FSH, testicular volume, and varicocele.

Limitations, reasons for caution

Mild kidney function impairment characteristics were found in 9% of asymptomatic and unaware patients presenting for primary infertility investigation. Age and the rate of comorbidities are associated with reduced eGFR. Wider implications of the findings: This novel finding confirms growing data on a significant association of male infertility with a poorer overall male health status.

Trial registration number

Not applicable

O-207 Which infertile patients mostly deserve to have a sperm DNA fragmentation index done? Findings from a cross-sectional study

Study question

Current scientific guidelines do not clearly suggest which patients would benefit the most from a sperm DNA fragmentation (SDF) test.

Summary answer

We aimed to investigate potential predictive factors for altered SDF in a homogenous cohort of white-European men presenting for primary couple’s infertility.

What is known already

High SDF has been associated with reduced fertilization rates, reduced chances of natural conception and an increased risk of early pregnancy loss.

Study design, size, duration

Data from 478 consecutive men with normal or altered SDF were analysed. Infertility was defined according to the WHO criteria. Semen analysis, SDF (according to SCSA) and serum hormones were measured in every patient. Health significant comorbidities were scored with the Charlson Comorbidity Index (CCI). Altered SDF was considered with a threshold of > 30%.

Participants/materials, setting, methods

Descriptive statistics compared the overall characteristics of patients with normal SDF and altered SDF. Logistic regression analysis tested potential predictors of altered SDF. ROC curve was used to test the accuracy of the model in predicting SDF alteration

Main results and the role of chance

Of 478 patients, 253 (57.7%) had altered SDF. Median (IQR) age and BMI of the whole cohort were 38 (35-42) years and 25.1 (23.3-27.1) kg/m2 respectively. Patients with altered SDF were older (median (IQR) age: 39 (36-43) vs. 37 (34-38) years, p < 0.0001), had lower sperm concentration (5 (1.1–18) vs. 17 x106/mL (6–38.8), p < 0.0001), testicular volume (15.1 (12 –20) vs. 16.8 (12 – 25) Prader, p = 0.0005), and total motile sperm count (TMSC) (1.8 (0.21–10.71) vs. 11.8x106 (2–37.26), p < 0.0001). Conversely, men with altered SDF had higher FSH (6.1 (3.85–9.7) vs. 4.8 (3.85 – 7.9) mIU/mL, p < 0.0001) and prolactin levels (9.8 (7.43–14.04) vs. 8.3 (6.6–11.3) pg/mL, p = 0.0004) than those with normal SDF. At multivariable logistic regression analysis, patients’ age >35 years (OR: 2.45, p = 0.0009), FSH > 8.0 mIU/mL (OR: 2.23, p < 0.0001) and lower TMSC (OR: 2.04, p = 0.002) were identified as indipendent predictors of altered SDF, after adjusting for testicular volume and CCI≥1. ROC curve (Figure 1) revealed that the model has a good predictive ability to identify patients with SDF alteration (AUC: 0.72, 95%CI: 0.67 - 0.77).

Limitations, reasons for caution

It is a retrospective analysis at a single, tertiary-referral academic centre, thus raising the possibility of selection biases. In spite of this, all patients have been consistently analysed over time with a rigorous follow-up, thus limiting potential heterogeneity in terms of data reporting

Wider implications of the findings

Primary infertile men older than 35 years, with high serum FSH and low TMSC at baseline are the ones who mostly deserve a SDF test over their diagnostic work-up and that would potentially benefit the most of certain treatments to improve SDF value, thus increasing chances of conceiving.

Trial registration number

Not applicable

P–027 Does air pollution impact on semen parameters? Findings from a real-life cross-sectional study in white-European infertile men

Study question

We aimed to investigate the association between air pollutants levels and semen parameters in a cohort of white-European men seeking medical attention for couple’s infertility.

Summary answer

We found that Pm10, Pm 2.5, and NO2 levels were negatively associated with sperm morphology.

What is known already

Air pollutants levels have been monitored closely for environmental and research issues in industrialized countries.

Study design, size, duration

Data from 156 infertile men consecutively assessed between 01/2019 and 12/2020 were analysed.

Participants/materials, setting, methods

Semen analyses were based on 2010 WHO reference criteria. We analysed the annual average level of the main markers of air pollution (Pm10, Pm2.5, and NO2) between 2014–2018 (Legambiente, 2020, Annual dossier series on air quality in Italy) relative to patients’ addresses of the last 5 years. Health-significant comorbidities were scored with the Charlson Comorbidity Index (CCI). Descriptive statistics and linear regression analyses were used to test the association between air pollutants and semen parameters.

Main results and the role of chance

Overall, median (IQR) age and BMI were 37 (33–41) years and 25.1 (23.4–27.3) kg/m2, respectively. A CCI≥1 was found in 12 (7.7%) men, and 47 (30.1%) participants were smokers. As for sperm parameters, semen volume, sperm concentration, sperm progressive motility and normal sperm morphology were 3 (2–4) ml, 18 (5–45.5) x106/ml, 32 (22–45)% and 2 (1–3)%, respectively. Pm10 was negatively associated with sperm morphology (ß: –0.580, p = 0.001). Furthermore, Pm10 was found to be an independent predictor for sperm morphology worsening (ß: –0.729, p = 0.006) (Fig.1A), after adjusting for age, BMI, CCI and smoking status. Similarly, Pm2.5 levels were negatively associated with sperm morphology (ß: –0.595, p = 0.009) (Fig.1B). After adjusting for the same variables, the association between Pm2 and sperm morphology remained significant (ß: –0.724, p = 0.015) (Fig.1C). NO2 levels were found to be associated with sperm morphology worsening after adjusting for age, BMI, CCI, and smoking status (ß: –0.471, p = 0.006).

Limitations, reasons for caution

It is a retrospective analysis at a single, tertiary-referral academic centre, thus raising the possibility of selection biases. Moreover, markers of air pollutions divided by residence may not completely evaluated the single patient exposure.

Wider implications of the findings: In this cross-sectional study we found that Pm10, Pm 2.5, and NO2 levels were negatively associated with sperm morphology, while they were not consistently associated with an increased risk of other abnormal sperm parameters in infertile men. Further studies are needed to characterize air pollution effects on sperm parameters.

Trial registration number

Not applicable