Objective Human papillomavirus (HPV) surveillance is important to monitor the effectiveness of national HPV vaccination programmes. Positivity of HPV in urine in men varies with different sampling methods. We aimed to determine the positivity for detection of HPV-6/11 in urine samples among men in relation to the position of genital warts and circumcision status.
Method We analysed stored chlamydia-positive urine specimens in young heterosexual men aged less than 25 years attending Melbourne Sexual Health Centre, Australia, between 2004 and 2015, for HPV genotypes. Positivity of HPV-6/11 and high-risk genotypes were stratified according to the position of genital warts and circumcision status. Positivity of HPV-6/11 was calculated using diagnosis of warts as the gold standard. Warts were classified as proximal penile warts from suprapubic area to midshaft of penis, and distal penile warts from distal shaft of penis to meatus.
Results Of the 934 specimens, 253 (27.1%) men were positive for any HPV and 82 men (8.8%) had genital warts. The ORs of HPV-6/11 detection in urine were 4.63 (95% CI: 1.68 to 12.78) and 40.20 (95% CI: 19.78 to 81.70) times higher among men who had proximal penile warts and distal penile warts, respectively, compared with men who did not have genital warts. Circumcised men were less likely to have high-risk HPV (OR 0.31; 95% CI: 0.14 to 0.65) than uncircumcised men. Uncircumcised men were more likely to have distal penile warts than circumcised men (OR 8.22; 95% CI: 1.34 to 337.46).
Conclusion Positivity of HPV-6/11 in urine increases greatly in men with distal penile warts. Circumcised men are less likely to have distal penile warts, any HPV or high-risk HPV detected. Urine is likely to be an alternative sampling method for HPV-6/11 surveillance programme in men in countries with low circumcision rates.
- human papilloma virus
- genital warts
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Human papillomavirus (HPV) is the most common sexually transmitted viral infection globally, although the prevalence of genital warts and vaccine-targeted HPV has fallen rapidly after the introduction of HPV vaccination programme.1–4 Australia started the school-based quadrivalent HPV (4vHPV:16/18/6/11) vaccination programme for young females in 2007. Dramatic declines in vaccine-targeted HPV and the incidence of genital warts have subsequently been observed among young women in Australia.5–7 Large declines in vaccine-targeted HPVs and genital warts have also been seen among unvaccinated heterosexual men, suggesting men have benefited from herd protection through the female-only HPV vaccination programme.5 7–9
A number of countries such as the USA, Canada and Australia have established surveillance programmes to monitor the impact of their HPV vaccination programmes in men and women. A correct and accurate sampling method is important for HPV surveillance, but an optimal sampling method for screening in men is controversial. A review has shown that large variation is found in HPV detection in both urine samples (ranging from 0.9% to 66.7%) and penile swabs of different sites (ranging from 10% in urethra to 50% in penile shaft).10
We hypothesised that variation in positivity of HPV detection from urine in men may be related to the site of the HPV infection on the penis and the chance that the urine came into contact with the genital warts while the urine was being passed in individuals with genital warts infection. We therefore assessed HPV-6/11 positivity in urine, stratified by location of warts and circumcision status.
Study design and population
This was a retrospective study on stored urine specimens from heterosexual men aged ≤25 years attending the Melbourne Sexual Health Centre (MSHC) who were diagnosed with Chlamydia trachomatis. MSHC is the largest public sexual health service in Victoria, Australia. MSHC provides about 40 000 consultations each year, and about 25% consultations are heterosexual men, of whom about 28% are aged ≤25 years and more than 85% of heterosexual men are tested for chlamydia.11 All chlamydia-positive specimens have been routinely stored in a −80°C freezer at MSHC since 2004, unless the patients declined to provide consent, which is rare.
Detailed methods on data collection and laboratory testing methods were reported elsewhere.8 In brief, heterosexual men were defined as men who have had sex with women but not with men in the last 12 months. Stored urine specimens from heterosexual men aged ≤25 years attending MSHC between 1 July 2004 and 30 June 2015 were used in the study. For men with recurrent chlamydial infections over the study period, only the first positive specimen was used in this analysis. All specimens were tested and genotyped for HPV using PapType assay (Genera Biosystems, Scoresby, Victoria, Australia).8 We calculated the positivity of the following HPV genotype groups: any HPV genotypes (6, 11, 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, or 68), vaccine-targeted low-risk HPV genotypes (6/11) and high-risk HPV genotypes (16/18/31/33/35/39/45/51/52/56/58/59/66/68).
The demographic data of individuals, clinical diagnoses of genital warts (including physical examination findings and the location of the genital warts on penis) and circumcision status were collected by ETA from individuals’ medical records. Inconclusive examination findings were discussed with CKF and EPFC, and a consensus was reached. Urethral swabs and specimens where there was no record in the clinical notes of a physical examination at the time of wart diagnosis were excluded. Location of warts was divided into three groups: (1) proximal penile warts (included base of penis, proximal shaft and midshaft or suprapubic region); (2) distal penile warts (included sites that were located at the meatus, frenulum, prepuce, glans penis, corona or distal shaft); and (3) no visible warts on physical examination. Proximal penile warts were in locations unlikely to be in contact with urine such as the base of penis, proximal shaft and midshaft or suprapubic region. Distal penile warts included sites that were in close contact with urine such as the meatus, frenulum, prepuce, glans penis, corona or distal shaft.12 Ethical approval was obtained from the Alfred Hospital Ethics Committee, Melbourne, Australia (approval number 241/15).
Positivity of any HPV, HPV-6/11 and high-risk HPV genotypes were calculated in men by the presence and location of warts and circumcision status. The 95% confidence interval (CI) of HPV-6/11 positivity were calculated by using the binomial ‘exact’ method. Univariate and multivariate logistic regression analyses were performed to examine the association between the presence and location of genital warts (proximal vs no warts; distal vs no warts) and HPV positivity. Circumcision and location of genital warts were included in the multivariate logistic regression analyses. Similar analyses were carried out to evaluate the association between circumcision status in men (circumcised vs uncircumcised; unknown circumcision status vs uncircumcised) and HPV positivity . Crude odds ratio (OR), adjusted odds ratio (aOR) and its 95% CI were calculated. An association between circumcision and location of warts in men with reported circumcision status was evaluated using univariate logistic regression analysis; OR and its 95% CI were calculated.All analyses were performed using Stata version 13 (StataCorp, College Station, Texas).
There were 1466 individual heterosexual men with stored positive urethral or urine chlamydia specimens between 1 July 2004 and 30 June 2015. We excluded a total of 532 individuals (490 with no physical examinations recorded, 38 with urethral specimens, 3 whose medical records were unavailable for review and 1 with no description of the location of warts). A total of 934 eligible individuals with urine specimens and physical examinations were included in this analysis.
Of the 934 men, 82 (8.8%) men were diagnosed with genital warts on the day of chlamydia diagnosis, 38 (4.0%) men had only proximal penile warts and 44 (4.7%) men had distal penile warts. There were 7 (0.7%) men who had warts on both proximal and distal parts of penis, and they were included in the group with distal warts.
HPV positivity in urine
Table 1 shows that positivity of HPV-6/11 in urine among men with distal penile warts (56.8%) was significantly higher than men with proximal penile warts (13.2%) (p<0.001). Of the 852 men without warts, 27 (3.2%) tested positive for HPV-6/11. The crude OR of HPV-6/11 positivity were 4.63 (95% CI: 1.68 to 12.78) and 40.20 (19.78 to 81.70) times higher among men who had proximal and distal penile warts, respectively, compared with men who did not have genital warts. There was no significant difference in high-risk HPV positivity in relation to location of warts in both circumcised and uncircumcised men (p<0.05).
Circumcision status and HPV positivity
Table 1 shows circumcised men had lower odds of having high-risk HPV (OR 0.31; 95% CI: 0.14 to 0.65) compared with uncircumcised men (table 1). Similar trends were noted for HPV-6/11 although not statistically significant.
Location of genital warts and HPV positivity in uncircumcised men
Positivity of HPV-6/11 in urine varied significantly by the location of warts in uncircumcised men. Of the 519 uncircumcised men, the positivity of HPV-6/11 was 22.90 (95% CI: 9.73 to 53.90) times higher in men with distal warts compared with men without warts or with proximal warts (p<0.001). However, the positivity of high-risk HPV was not statistically different among uncircumcised men by location of warts (proximal warts OR 1.58 (95% CI: 0.47 to 5.40), distal warts OR 0.43 (95% CI: 0.15 to 1.30).
Circumcision status and location of genital warts
Of the 519 (519/934, 55.6%) men who had circumcision status recorded in the clinical records, 425 (425/519, 81.9%) men were uncircumcised and 94 (94/519, 18.1%) men were circumcised. Fifty-three out of 519 (10.2%) men had genital warts; circumcised men were less likely to have distal penile warts (0%; 0/94) than uncircumcised men (7.8%; 33/425) (p<0.001) (table 2).
This study shows that positivity of HPV-6/11 in the urine of men with genital warts was much greater in cases whereby warts were more likely to come into contact with urine. We also showed that the location of genital warts was strongly related to circumcision status and that uncircumcised men were more likely to have distal warts in close contact with urine. In addition, circumcised men were less likely to have high-risk HPV detected than uncircumcised men, suggesting circumcision might be protective against high-risk HPV.
A number of studies have shown large variations in HPV positivity in urine (from 6% to 73%).7–9 13–17 However, to date, no study has been able to explain this large variation. Our data are the first to suggest that it may be due to the location of genital HPV infection, which at least for warts was different by circumcision status. We found that uncircumcised men were 8.22 times more likely to have distal penile warts compared with circumcised men (table 2); this finding is consistent with a previous study conducted in a sexual health clinic in Seattle in 1988.12 Furthermore, our study has shown that circumcised men are less likely to have any HPV as well as high-risk HPV detected. This is consistent with two published meta-analysis studies showing circumcised men have a lower genital HPV compared with uncircumcised men.18 19 Previous reviews have also demonstrated a strong evidence showing circumcision is a strong protective factor for genital HPV incidence (relative risk (RR) 0.75) and invasive penile cancer (OR 0.33).18 20 21
Our finding shows that circumcision status influences the detection of HPV genotypes in urine. In addition, there is a strong assoication between HPV-6/11 and distal warts in uncircumcised men and this is because the infection of HPV-6/11 in circumcised men occurs less commonly near urine. What the optimal specimen for penile HPV detection in men has been debated. Weaver et al compared HPV detection in urine and penile swabs among 317 men in the USA. Penile swabs were collected by clinician from the foreskin, and it showed that penile swab (28%) had a higher positivity for HPV detection compared with urine (6%) and no association between circumcision status and HPV detection on the penile swabs (31% in circumcised men vs 29% in uncircumcised men, p=0.66).13 However, these results may be influenced by high circumcision rates in the USA. Another US study conducted by Hernandez and colleagues compared HPV detection using penile swabs from multiple sites of the penis and scrotum as well as urine samples in 379 men according to their circumcision status. It showed that uncircumcised men had higher detection of any HPV compared with circumcised men from penile shaft swabs (60% vs 50%; p=0.152) and in urine samples (16% vs 8%; p=0.139); however, the difference between two groups are not significant, although the sample size was small.15 The findings of these studies are consistent with our observation that the site of HPV infection influences the positivity of a urine sample and that circumcision influences the site of infection.
There are a number of factors to take into consideration in our study. First, our study population was men who have sex with women only. Positivity of HPV detection may differ in men who have sex with men due to different prevalence of genital warts and HPV positivity between the two groups. Second, this study was conducted in a single sexual health service and among men who tested positive for chlamydia. These men may be more sexually active and hence may have a higher risk of genital warts and testing positive for HPV compared with men in the general population. Furthermore, we only included men aged ≤25 years, but prevalence of HPV and genital warts vary across different age groups.9 22 23 Hence, our results may not be generalisable to the whole male population. Third, our findings on association between circumcision status and HPV detection may be influenced by several potential confounding factors such as sexual practices, number of sexual partners and vaccination status. Finally, a small number of men were diagnosed with genital warts (n=81). This is because genital warts have become less common in heterosexual men in Australia over time due to the herd protection received from the female HPV vaccination programme.6–9 Having a small sample size could limit the statistical power and precision for some associations.
Large variations in positivity of HPV detection in male populations from urine samples have been reported internationally. We provide a plausible explanation for this observation based on the rate of circumcision in the population, the location of warts and the likelihood of urine contact with the genital warts. Although our study shows higher detection of HPV-6/11 in urine in men with distal penile warts especially in uncircumcised men, we did not assess the site of high risk or other HPV infection on the penis and so we are unable to comment on whether HPV types other than HPV-6/11 preferentially infect the proximal penis. A study by Tobian et al 24 found that high-risk HPV was more frequently detected in the coronal sulcus than penile shaft in both circumcised and uncircumcised group. However, more evidence is needed to assess if there is indeed a trend for different penile sites to harbour specific high-risk HPV types, and if these are dependent on circumcision status. If other types of HPV preferentially infect the proximal penis like genital warts (or HPV-6/11) do, then in circumcised populations that use urine for surveillance, this may also result in an underestimate of the prevalence of other types of HPV. Alternative sampling methods should be used for populations with high rates of circumcision. Our findings suggest that urine could be used as an alternative sampling method for men in HPV-6/11 surveillance in countries with low circumcision rates.
Detection of human papillomavirus (HPV) 6/11 in urine in men is greater in men with distal penile warts (in close contact with urine).
Location of genital warts is strongly related to circumcision status.
Circumcised men are less likely to have distal penile warts and high-risk HPVs than uncircumcised men.
Handling editor Jackie A Cassell
Contributors ETA, CKF and EPFC conceived the study and design. JAD performed all HPV genotyping. ETA and EPFC performed data analyses. ETA conducted chart review and wrote the first draft of the manuscript. All authors helped with interpretation of data, manuscript editing and approved the final version.
Funding This work was supported by the National Health and Medical Research Council (NHMRC) programme grant (number 568971). EPFC and JJO are supported by the Early Career Fellowships from the Australian NHMRC (numbers 1091226 and 1104781, respectively).
Competing interests The authors do not have a commercial or other association that might pose a conflict of interest.
Patient consent Obtained.
Ethics approval The Alfred Hospital Ethics Committee, Melbourne, Australia.
Provenance and peer review Not commissioned; externally peer reviewed.
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