The Acceptability and Cost of a Home-based Chlamydia Retesting Strategy

Findings From the REACT Randomised Controlled Trial

K. S. Smith; J. M. Kaldor; J. S. Hocking; M. S. Jamil; A. M. McNulty; P. Read; C. S. Bradshaw; M. Y. Chen; C. K. Fairley; H. Wand; K. Worthington; S. Blake; V. Knight; W. Rawlinson; M. Saville; S. N. Tabrizi; S. M. Garland; B. Donovan; R. Guy


BMC Public Health. 2016;16(83) 

In This Article


REACT Trial Methods

The REACT trial methods are described in detail elsewhere.[26] Briefly, in this unblinded RCT, individuals were randomised in a 1:1 ratio to either an SMS reminder and postal home-collection kit (intervention–home arm), or an SMS reminder and clinic testing (control–clinic arm). Participants in the home arm had the option to return to the clinic for retesting if they preferred. The trial was conducted in two public sexual health clinics in Australia (Melbourne and Sydney Sexual Health Centres). Participants included three risk groups: women, heterosexual men and MSM. To be eligible participants had to be: aged 16 years or above; with a diagnosis by nucleic acid amplification tests (NAAT) of chlamydial infection (genital infection in heterosexual men and women, and urethral and/or rectal infection in MSM); and reside in the jurisdiction serviced by the clinic for the next six months. They were also required to have a mobile phone. Patients were excluded if: they were unwilling or unable to comply with all the requirements of the protocol; they could not speak English; or were HIV positive or a current sex worker. Eligible patients were asked by study nurses for their permission to pass on their contact details to a member of the research team. If the patient agreed, a member of the research team contacted the patient to explain the trial requirements and undertake a verbal consent process as per ethics committee approval.

For participants in the home arm, 3 months after chlamydia diagnosis, an SMS was sent by the research team to let the patient know their retest was due and a kit would soon be mailed to them. The home collection kit contained the collection device/s (women, self-collected vaginal swab; heterosexual men, UriSwab for urine collection (Copan Diagnostics, Murrieta, CA); MSM, UriSwab and rectal swab), plus illustrated collection instructions, a laboratory request form, and a prepaid envelope. The swabs and request form were pre-labelled with identifying information. The collection kit was mailed to the patient in an unmarked package by the research team at 3 months. Patients were instructed in a covering letter to collect their specimen/s, package them according to the provided instructions, and mail them to the laboratory in the prepaid envelope.

For participants in the clinic arm, 3 months after chlamydia diagnosis, patients were sent an SMS reminder by the clinic to remind them to return to the clinic for retesting. This is routine practice at the two participating clinics.

The main outcome measures were the percentage of participants retested at 1–4 months after chlamydia diagnosis and the percentage in each arm with repeat positive tests, by risk group and overall, analysed by intention to treat, and these have been recently reported.[27] The focus of this paper is on the secondary outcomes which include: the acceptability of home-based retesting for chlamydia and SMS reminders; and the cost of home versus clinic-based retesting. These are described in detail below.

Acceptability and Cost Analysis Methods

Acceptability. REACT participants (200 women, 200 heterosexual men, 200 MSM) were sent an SMS 4.5 months after enrolment (after ascertainment of the primary outcome), asking them to complete an online survey (Additional file 1 The SMS contained the study website and the participant's code which was linked to their patient details captured at consent. The survey captured: participant demographics; living situation (with parents or others); whether the participant retested and if not, reasons for not retesting; and the acceptability of SMS reminders (all participants). Those randomised to the home arm were also asked about their level of comfort with having a home test kit mailed to them, their ease and level of confidence with self-collection of specimens, problems with specimen collection, preferred methods of retesting in the future (home, clinic or either) and their preferred method of receiving home test kits in the future. The majority of questions used a Likert scale format to measure the participant's response, or a choice of responses plus free-text space was provided for some questions. For the following questions: reason for not retesting, problems with specimen collection and reasons for retesting preference; participants could choose more than one option. Participants who did not complete the survey were sent a second SMS two weeks later. If the survey was still not completed within another two weeks, they were sent a third SMS asking if they would prefer the survey to be mailed to them or to complete it by telephone. On completion of the survey, participants were sent a $40 AUD voucher, irrespective of retesting.

The following clinical variables collected at the initial screening consultation were extracted from the clinic's patient management system and linked with the survey results using the study identifier: date of birth, country of birth, condom use in the last 3 months (consistent, inconsistent, or never), number of sexual partners in the last 3 months, previous chlamydia diagnoses (ever), and anal and urogenital symptoms.

A chi-square test was used to assess if there were any differences in baseline characteristics: risk group, demographics, sexual behaviour or STI clinical information (previous chlamydia diagnosis or STI symptoms), between survey respondents in the home versus the clinic arm. A chi-square test was also used to assess if there were any differences in demographics, sexual behaviour and acceptability of home testing according to the preferred method of retesting (home versus clinic/no preference).

Cost Analysis. We assessed the cost of the chlamydia home retesting intervention compared to clinic based retesting from the perspective of the health system only. Based on routine practice at the participating sexual health services and the home-testing pathway used in the trial, a flowchart was constructed including all the steps from the initial chlamydia test to the retest, in both the clinic-based strategy and the home strategy (initial consultation, notification of a positive result, treatment consultation, SMS, retest) (Fig. 1). Based on information provided by the participating clinics, we assumed that 40 % of patients were treated at the initial consultation on the basis of symptoms or as contacts, and didn't require a further treatment visit.

Figure 1.

Flowchart of retest pathway

Clinic Costs

The two participating clinics conducted an audit of the last 20 clients who retested in each of the three risk groups, and provided the length of the consultation and staff type seen during the screening, treatment, and retesting visits. We then calculated the average consultation length for each risk group at each step. Additional information sourced from the clinics included the cost of SMS reminders, equipment, antibiotic treatment and telephone calls to inform clients of their results. Labour costs were estimated based on the length of consultation time, staff type and average salary including on-costs (25 %) and infrastructure (30 %). The cost of diagnostic testing was based on the fees charged by the laboratories (which included the cost of the test as well as the testing equipment, the request form, administration, courier and infrastructure). Using the above data, the clinical and laboratory costs of the entire testing pathway including registration, screening, treatment and retesting for clinic and home based testing was calculated.

Home Collection Costs

The home collection costs were the same as for the clinic arm up to the retesting step. Costs for the home retest step included the cost of assembling the kit (based on the length of time taken and the research team member's salary including on-costs and infrastructure as above), equipment additional to that which was supplied by the laboratory (saline for rectal swabs and postal satchels), return postage and the laboratory fee (which included the cost of the test, testing equipment, request form and administration).

Overall Costs and Cost Per Infection Detected

Based on the costs above, the costs of the entire clinic pathway versus the home test strategy were calculated. We also calculated the expected costs of clinic and home testing based on the uptake of retesting in each arm of the REACT trial, taking into consideration that 27 % of participants in the home arm chose to retest at the clinic. Based on these costs and repeat infections detected in each arm, the cost per infection detected for clinic and home testing was calculated by dividing the total costs for all participants in each arm by the number of infections detected.

Ethics Approval

This study was approved by the Alfred Health Human Research Ethics Committee (HREC), South Eastern Sydney and Illawarra Area Health Service HREC and the University of New South Wales HREC.