Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are the most prevalent bacterial sexually transmitted infections (STIs) diagnosed worldwide [1]. General practitioners (GPs) have a major role in STI healthcare, since most STIs are diagnosed by GPs and STI clinics [2–6].

A test of cure (TOC) within 3–5 weeks after the completion of CT treatment is internationally not recommended because of possible false-positive results leading to overtreatment [7–9]. The British Association for Sexual Health and HIV in cooperation with the Royal College of General Practitioners, as well as the 2012 European guideline on the diagnosis and treatment of gonorrhoea in adults, recommend a TOC for all patients who tested positive for NG two weeks after treatment due to the increasing antimicrobial resistance of NG [10, 11]. However, the American Centers for Disease Control and Prevention only recommend an NG TOC in the case of oropharyngeal NG when treated with an alternative regimen [9]. The Dutch general practitioner guideline does not recommend a CT TOC nor an NG TOC, except for specifically indicated cases [12].

Repeat infections within 3–12 months after CT/NG diagnoses are common, totaling up to 32% for CT and up to 40% for NG [13, 14]. For effective CT/NG control, retesting CT/NG positives within 3–12 months is recommended by the Centers for Disease Control and Prevention as well as the British Association for Sexual Health and HIV [9, 10]. Moreover, a modeling study suggested that the most effective control strategy for the treatment of resistant NG is to retest NG positives, rather than testing and treating more patients [15]. Furthermore, the Dutch GP guideline has been revised since 2013 and recommends that GPs advise CT-positive patients to consider retesting within a year [12]. However, no recommendations are given for retesting NG-positive patients [12].

The majority of CT and NG positives seen by GPs are not retested [16–18]. However, retesting rates may have been underestimated, as patients could have a TOC or a retest at another STI care provider like the STI clinic or the hospital [16]. Insight into TOC and retesting rates, including associated factors among GPs and patients, is vital to inform and improve CT and NG control.

Extragenital CT infections are common among men who have sex with men (MSM) and women [19]. International guidelines recommend extragenital testing based on indication; that is, self-report of anal sex and symptoms [7, 10]. However, studies showed that extragenital CT infections are common among MSM and women without indication, which suggests routine screening at extragenital sites among MSM and women [19, 20]. According to the Dutch GP guideline, additional anorectal CT/NG testing in MSM and an indication of anal sex or anal symptoms is recommended [12]. For NG, additional oropharyngeal testing should be performed for commercial sex workers and MSM who report oral sex or oropharyngeal symptoms. According to recent studies among GPs in the Netherlands, extragenital CT and NG testing was rarely performed [2, 18]. However, an earlier Dutch study estimated that ~9% of male patients with a STI-related GP visit are MSM, for whom extragenital testing is recommended [12, 21].

The socioeconomic status (SES) of patients has been linked to various infectious diseases like CT and NG [2, 18, 22]. However, it remains unknown whether TOC and retesting practices differ between GP practices in low, middle and high SES areas. Such analyses that include the SES of GP practice areas could be helpful in advising GPs about their TOC and retest practices to optimize CT and NG control at a local level.

Here, we assessed CT and NG TOC and retesting practices of GP practices in different SES areas, taking account of TOC and retesting of patients at other STI care providers as well as extragenital testing, in order to inform and optimize local test practices of GP practices.

This retrospective cohort analysis of 48 Dutch GP practices shows that a TOC was performed in approximately 20% of the CT patients, especially at GP practices in low SES areas and in patients with a younger age (<25). Furthermore, 1 out of 4 patients had an NG TOC, which is generally not recommended in the Dutch GP guideline. However, an NG TOC is recommended in international guidelines due to increasing antimicrobial resistance of NG [9–11]. Most CT (76%) and NG (85%) patients did not have a retest at their GP. Overall, 12% retested CT positive and 0% retested NG positive. Due to the low number of CT and NG retests, repeat infections were likely missed. A comparable proportion of the NG patients were retested at the GP practice (15%) and at other STI care providers (12%), while the percentages for CT retests were 24% at the GP practice and 6% at other STI care providers. Furthermore, extragenital CT and NG testing was rarely performed at GP practices (0.3%), in which extragenital infections were likely missed.

Several studies have been performed assessing CT/NG test practices among different STI care providers [16, 23–26]. However, these studies only include patient-related factors and lack GP characteristics. We included these factors to draw up recommendations specifically for GPs in order to enhance CT/NG control. Moreover, we provided evidence that the retesting rates of patients initially seen by their GP are underestimated; that is, we showed that the rate of retesting NG patients at other STI care providers (12%) is comparable to the rate of retesting at the GP practice (15%). Despite the small numbers, analyses of NG test practices are necessary, as following up on NG positives seems to be the most effective control strategy for the treatment of resistant NG [15]. Furthermore, we analyzed recent data from before and after the revision to the Dutch GP guideline in order to assess current retesting practices of GPs. However, no difference between the two time periods was observed (Tables 1 and 2). Finally, a further strength is that we assessed whether GP practices in our study area indeed send their tests to the regional laboratory, in which we estimated that 81% (39/48) of the GP practices did.

A general limitation of the study was that information on patients’ sexual behavior and on the characteristics of or reasons for testing was unavailable. Such reasons may include financial reasons. STI tests at the GP are within patients’ deductibles in healthcare insurances, whereas STI tests at the STI clinic are free of charge for risk groups (age <25, MSM and commercial sex workers) [23, 27]. An earlier study in the southeastern part of Limburg showed that CT retesting rates were lower for GPs (23.0%) in comparison with the STI clinic (33.4%) and gynecologists (30.3%) [17]. In addition, we operationalized the outcomes according to international guidelines with a cut-off point of three months. As a result, we were unable to assess whether a CT/NG TOC or retest was also defined as such by the treating GP. A limitation for the outcome TOC was that we were unable to assess whether a CT or NG TOC was justified according to the Dutch GP guideline; that is, in the case of pregnancy, persistent symptoms, reexposure to untreated source or lack of treatment with first choice of treatment [12]. In addition, the use of the same time period for assessing TOC for both CT and NG is debatable. While a TOC for CT is not advisable, a TOC two weeks after NG treatment is internationally recommended [10–14]. However, to enable a comparison between CT and NG, we applied equal TOC periods [12]. Still, the exact time for performing an NG TOC is under debate [28, 29].

We showed that almost 1 in every 5 patients had a CT TOC. Moreover, almost two-thirds of the positive CT TOC were diagnosed within 3 weeks of the positive screening test, which is strongly not recommended and can be false positive results leading to overtreatment [8, 9, 30]. If indicated, a CT TOC should be performed at least 3 weeks post treatment [7, 9, 12]. An Australian study showed that 25% of the patients who tested positive for CT at the GP made a new test request within six weeks, which is also not recommended in the Australian GP guidelines [16]. An NG TOC was performed in almost 1 in 4 patients, which is not recommended in the Dutch GP guideline. However, forgoing a TOC after NG treatment is debatable, as international guidelines recommend a TOC two weeks post treatment for all NG patients [10, 11] or patients with oropharyngeal NG and treated with alternative medication [9]. One patient had a positive TOC after 40 days of the positive screening test, which could be related to treatment failure [11]. Still, no cases of antimicrobial resistance have yet been reported in the Netherlands [15, 31].

A high proportion of CT repeat infections were diagnosed. Other studies showed higher retesting rates among GPs than our study, still retesting rates were low and likely infections were missed [16, 32]. Moreover, due to low rate of extragenital testing also extragenital infections were likely missed, since extragenital infections are common in MSM as well as in women without symptoms in STI clinic settings [19, 21]. However, this remains unclear for the GP population. Similar findings of low extragenital testing among GPs in another Dutch region confirm the likely generalizability of our study [2, 18].

According to the laboratory data (Fig 1), most CT and NG tests were performed by the STI clinic followed by GP practices. In the Netherlands, TOC rates are higher at GP practices compared to STI clinics, whereas retesting rates are higher at STI clinics compared to GP practices [17, 18, 23]. However, in other countries retesting rates seem higher at GP practices than STI clinics [16, 32].

According to previous studies, the number of positive CT and NG tests is highest among patients living in low SES areas [2, 18]. The SES of patients’ living areas was not associated with CT or NG TOC in the current study. However, most patients lived near the GP practice (<3 km; Tables 1 and 2). This fact could explain the higher CT TOC rate of GP practices in low SES areas in our study. Our results show that patients who tested for both CT and NG were more likely to retest for CT and NG in comparison with patients who only tested for CT (Table 1). Patients without an NG test are likely to be a low-risk group or to lack symptoms, as the Dutch GP guideline recommends an additional NG test in high-risk groups or when having symptoms [12]. An NG retest is not mentioned in the Dutch GP guideline [12]. Positivity of NG retesting was 0% in the current study, which may be explained by the low rate of retesting (~15%). Recently, another study among GPs in the Netherlands showed a retest positivity rate for NG of ~23% [18]. As studies which include positivity in NG retesting of GP patients are scarce, more research is needed for NG control optimization [18].

A CT TOC should never be performed within three weeks after CT treatment due to false-positive results what could lead to overtreatment [7–9]. A CT TOC is in general not needed but should be performed (1) in the case of pregnancy, (2) when having persistent symptoms or (3) when there is lack of treatment with first choice treatment, as described in the Dutch GP guideline [12]. An NG TOC is internationally recommended at least two weeks post treatment due to increasing antimicrobial resistance of NG [10, 11]. Unfortunately this is not recommended in the Dutch GP guideline [12]. All CT and NG patients should be retested within three to twelve months, despite that the minimum time of three months is not mentioned in the Dutch GP guideline [12]. Extragenital testing should be performed in all MSM and patients reporting anorectal intercourse or symptoms, as described in the Dutch GP guideline [12].

To facilitate retesting at the GP practice, GPs could consider using modern testing and communication strategies such as e-health. For example, GPs could, in collaboration with their diagnostic laboratory and public health services, send home sampling kits 3 to 12 months post treatment to improve retesting rates. Also automatic small text messages could be used. These two methods have shown to increase retesting rates in specific settings, but not in GP settings yet [23, 33]. Moreover, education and awareness of the importance of CT and NG testing could improve (re)testing rates at the GP practice [34].

Almost 1 in every 5 CT positives returned for a TOC. Especially GP practices in lower SES areas performed a CT TOC, which is not recommended. Most patients did not have a CT retest, although the high CT positivity at retesting (12%) demonstrates the need to encourage retesting of CT positives. The proportion of retesting for NG positives was also low (15%). Moreover, only 0.3% of the CT/NG consultations had patients tested on extragenital sites. As a result, infections or reinfections could have been missed.

A TOC for CT is not needed, whereas a TOC for NG should be performed. All CT and NG patients should be retested within three to twelve months. GPs should perform extra genital testing in all MSM and in all patients with anorectal intercourse or symptoms. The Dutch GP guideline needs to be reconsidered, especially regarding NG TOC and retesting as it is inconsistent with international guidelines.