The effect of introducing routine self-taken extra-genital swabs in a genitourinary medicine clinic cohort: a before and after study

Abstract

Starting July 2013, all patients attending a sexual health clinic who reported risk of extra-genital infection were offered self-taken extra-genital swabs. The study aim was to assess the detection rate of extra-genital infection since self-taken swabs were introduced. We compared patients diagnosed with chlamydia and gonorrhoea in six-month periods before (February–July 2012) and after (February–July 2014) the introduction of self-taken extra-genital swabs. There were 408 (98 gonorrhoea, 310 chlamydia) detected infections in the 2012 period and 404 (121 gonorrhoea, 283 chlamydia) in 2014. The rate of extra-genital chlamydia/gonorrhoea increased fourfold from 18/408, 4.4% to 77/404 19% (P < 0.0001). The rise was seen in both rectal (8/408, 2% vs. 40/404, 9.9%, P < 0.0001) and pharyngeal infection (10/408, 2.5% vs. 48/404, 11.8% P < 0.0001). Significant rises were seen in men who have sex with men in rectal (5/408, 1.2% vs. 28/404, 6.9% P = 0.001) and pharyngeal infection (10/408, 2.5% vs. 20/404, 5%, P = 0.02) and for women in rectal (3/408, 0.7% vs. 12/404, 3% P = 0.03) and pharyngeal infection (0/408, 0% vs. 20/404, 5%, P < 0.0001). In 100 consecutive patients having extra-genital swabs in each study period, self-swabbing rose from 0% (0/100) to 89% (89/100) P < 0.0001. The introduction of routine self-taken extra-genital swabs has led to a large rise in detected extra-genital chlamydia and/or gonorrhoea infection in men who have sex with men and women.

Keywords

Self-taken extra-genital swabs gonorrhoea chlamydia sexual health sexually transmitted infection screening

Introduction

Background knowledge

According to the 2014 Public Health England Infection Report, the most commonly diagnosed sexually transmitted infection (STI) in England was chlamydia.¹ The incidence of gonorrhoea rose by 19% from 2013 to 2014 and there continues to be a rise of STIs among men who have sex with men (MSM) and young heterosexuals.¹ Factors attributed to rises in STI diagnosis among MSM include increased extra-genital site testing, high rates of unsafe sex and serosorting.¹ There is evidence that treatments that may be given for genital chlamydia or gonorrhoea may not be adequate treatment for extra-genital infections. A 2015 meta-analysis showed a 19.9% difference in efficacy in favour of doxycycline over azithromycin for treatment of rectal chlamydia.² Similarly, spectinomycin has been shown to have poor efficacy at treating pharyngeal gonorrhoea.³ It is therefore important to continue testing extra-genital sites if we are going to reduce onward transmission and ensure that best therapy is used.

Extra-genital swabs have been shown to be effective at detecting chlamydia and gonorrhoea and are also preferred as they are non-invasive.⁴ Swabs used are usually taken for nucleic acid amplification tests for chlamydia and gonorrhoea. Although they are not formally approved for non-genital specimens, the assays have been clinically validated and are widely used for rectal and pharyngeal swabs.⁴ In asymptomatic MSM, self-taken extra-genital swabs are comparable in terms of outcome to clinician taken swabs and there is evidence that no significant clinical diagnoses will be missed.^4,5

Local problem

A total of 41% of patients attending the service are either young heterosexuals under 25 or MSM and as stated in Public Health England Infection report, these are the groups where STIs continue to rise. Many heterosexual women were reporting oral and anal sex, as well as vaginal sex, in the clinic cohort. In view of this, in July 2013, self-taken extra-genital swabs were offered routinely to all patients (heterosexual and MSM) who attended the department and who reported risk for extra-genital infection.

Study question

To assess the detection rate of extra-genital infection since the introduction of routine self-taken swabs.

Methods

Setting

The clinic has approximately 15,000 sexual health attendances each year in either booked clinics (15%) or the walk-in (85%) service. Patients are from diverse ethnic backgrounds with over 50% of attendees being Black British/Caribbean/African. Self-taken vulvo-vaginal swabs for chlamydia and gonorrhoea have been taken by female patients since 2000, with male genital infection detected by first-pass urine. Routine self-taken extra-genital swabs for chlamydia and gonorrhoea were first introduced in mid-2013, having been clinician-taken before then. Patients are instructed on how to do this by the health care worker and diagrams are present in the toilets where the patients take their own swabs.

Method of evaluation

We assessed all patients diagnosed with chlamydia and gonorrhoea in a six-month period between February 2012 and July 2012 when self-taken swabs had not been introduced in the department, we reviewed which sites were tested, infected and whether the swabs were self-taken or not. We then compared patients diagnosed with chlamydia and gonorrhoea between February 2014 and July 2014, after the introduction of self-taken swabs, looking at the same parameters. The rate of self-swabbing was determined in separate consecutive groups of 100 patients who had attended the clinic in the same periods. The assay used was the BD Probetec Strand Displacement Assay™.

Statistical analysis

A two tailed Fisher’s exact test was used to assess the differences between the two periods.

Results

Between 2012 and 2014, the rate of detected extra-genital chlamydia/gonorrhoea infections increased fourfold from 18/408, 4.4% to 77/404, 19% (P < 0.0001, Table 1). The rise was seen in both rectal (8/408, 2% vs. 40/404, 9.9%, P < 0.0001) and pharyngeal infections (10/408, 2.45% vs. 48/404, 11.8% P < 0.0001). Significant rises were seen in MSM in rectal (5/408, 1.2% vs. 28/404, 6.9% P 0.001) and pharyngeal infection (10/408, 2.5% vs. 20/404, 5%, P = 0.02, Table 1) and for women in rectal (3/408, 0.7% vs. 12/404, 3% P = 0.03) and pharyngeal infection (0/408, 0% vs. 20/404, 5%, P < 0.0001, Table 1). In these patients, rates of extra-genital self-swabbing rose from 0% (0/24) to 58.5% (141/241), P < 0.0001, Table 1. In separate samples of 100 consecutive patients having extra-genital swabs in each study period, self-swabbing rose from 0% (0/100) to 89% (89/100) P < 0.0001.

Table 1.

CT (Chlamydia trachomatis) and GC (gonococcal) infections diagnosed in two six-month periods in 2012 and 2014.

Sexually transmitted infection	February–July 2012	February–July 2014	P values
No. gonorrhoea diagnosed	98	121	NS
No. chlamydia diagnosed	310	283	NS
Sexual orientation of infected patients	No., % (95% confidence interval)	No., % (95% confidence interval)
Heterosexual	381, 93% (91–95%)	357, 88% (85–91%)	NS
Homosexual/Bisexual	27, 7% (5–9%)	47, 12% (9–15%)	NS
Rate of self-taken swabs in infected patients	No., % (95% confidence interval)	No., % (95% confidence interval)
Extra-genital swabs not taken	383, 94% (91–96%)	163, 40% (36–45%)
Clinician-taken extra-genital swabs	24, 5% (4–9%)	100, 25% (21–29%)	<0.0001
Self-taken extra-genital swabs	0	141, 35%(30–40%)
Unclear	1, 2% (0–2%)	0
Combinations of sites infected	No., % (95% confidence interval)	No., % (95% confidence interval)
Genital + pharyngeal	3	15
Genital + pharyngeal + rectal	0	7
Genital + rectal	5	12
Pharyngeal + rectal	0	4
Pharyngeal	7	22
Rectal	3	17
Genital only	390, 96% (93–97%)	327, 81% (77–84%)	<0.0001
Total extra-genital^a	18, 4% (3–7%)	77, 19% (16–23%)
Specific extra-genital sites infected	No., % (95% confidence interval)	No., % (95% confidence interval)
Pharyngeal	10, 2% (1–5%)	48, 12% (9–15%)	<0.0001
Non-pharyngeal	398, 98% (95–99%)	356, 88% (85–90%)
Rectal	8, 2% (1–4%)	40, 10% (7–13%)	<0.0001
Non-rectal	400, 98% (96–99%)	364, 90% (87–93%)

Extra-genital sites infected based on gender
Extra-genital sites infected	Male	P value^a	Female	P value^a
Pharyngeal 2014	28	0.004	20	<0.0001
Pharyngeal 2012	10		0
Rectal 2014	28	0.001	12	0.03
Rectal 2012	5		3

Extra-genital sites infected based on sexuality
Extra-genital sites infected	Homosexual	P value^a	Heterosexual	P value^a
Pharyngeal 2014	21 (20 MSM and 1 WSW^b)	0.02	27 (19 females and 8 males)	<0.001
Pharyngeal 2012	10		0
Rectal 2014	28	0.001	12	0.03
Rectal 2012	5		3

Note: MSM: men who have sex with men; WSW: women who have sex with women.

As a proportion of total CT/GC cases for that year.

Women who have sex with women.

Discussion

Main findings

The introduction of routine self-taken extra-genital swabs in the department has led to a large rise in detected extra-genital chlamydia and/or gonorrhoea infection, especially for MSM and women. Since the introduction of extra-genital self-swabbing, we noted a fourfold rise in the number and proportion of detected extra-genital chlamydia and/or gonorrhoea infections. Rises in extra-genital infection were seen in mostly in MSM and women. There was approximately a sixfold increase in detected rectal infections and a twofold increase in detected pharyngeal infections in MSM. In women, there was approximately a fourfold increase in rectal infection and a large rise in detected pharyngeal infections (from 0 to 20 cases). Regarding heterosexual males, there were no extra-genital infections detected in 2012 and in 2014, eight heterosexual males had an extra-genital infection, mainly pharyngeal. A total of 163 patients in the 2014 group did not have extra-genital swabs done because they were not at risk of extra-genital infections. Rates of self-taken swabs increased dramatically from 0 to 89% in those offered following their introduction, showing that they were acceptable to patients.

Relation to other evidence

Our findings are similar to those noted by Public Health England in the 2014 Infection Report for MSM.¹ Other studies have shown similar findings for rectal chlamydia in women.^6,7 Non-invasive collected specimens such as urine and self-taken vaginal swabs have enabled community screening programmes and are an acceptable alternative to screening.⁸ This acceptability has also been noted in extra-genital swabs and use of self-taken extra-genital swabs in MSM was found to be comparable to clinician swabs.⁴ Evidence on extra-genital infections in women remains variable. Some studies have shown rectal chlamydia in women who do not report anal sex.⁹ In another study, the prevalence of anorectal chlamydia in women was high and almost all women with anorectal chlamydia had concurrent urogenital chlamydia.⁶ A study in Canada has suggested universal rectal testing for chlamydia in high-risk women.⁷ Findings from these studies were similar to our study where we found an increase in rectal chlamydia infections in women. According to UK chlamydia guidelines,¹⁰ there is still a paucity of good data regarding pharyngeal chlamydia infections in women; however, in our study, we noticed an increase in detected pharyngeal infections in women over the two time periods.

Limitations

Our study was retrospective therefore we did not compare self-taken with clinician-taken swabs; however, there is already good evidence that they are comparable.⁴ As there was a high uptake of self-taken swabs, we assumed acceptability to patients, however, we could not ascertain this was the case as this was retrospective. Also the technique of self-swabbing was not assessed. However information was given to the patients by the clinician and posters are available in the toilets, which illustrate and explain self-swabbing technique.

Interpretation of results

This study shows that after the introduction of self-taken extra-genital swabs, there was a significant rise in detected extra-genital infection. As a result, we were able to ensure that suitable antibiotic treatment could be given, bearing in mind that some antibiotics are less effective for extra-genital infection.

Conclusion

High rates of chlamydia and or gonorrhoea infections were found in extra-genital sites among MSM and women following the introduction of routine self-taken swabs for those at risk. The study highlights the importance of continuing extra-genital testing in at-risk patients and the high rate of self-swabbing shows that this is acceptable to patients.

Footnotes

Acknowledgements

We would like to acknowledge the efforts of the clinic staff.

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

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