METHOD

Patients were eligible for this study if they were heterosexual, over 16 years of age, diagnosed with chlamydia, and their sexual partner(s) resided in the United Kingdom. All patients, who met the eligibility criteria of this study during October and November 2000 were issued with a CS1 on referral to the health adviser, as per clinic protocol. For 3 months, starting in October, the number of contact attendances at Mortimer Market Centre (MMC) or elsewhere for each index patient was recorded using a standardised data collection sheet.

During February and March 2001 all eligible patients diagnosed with chlamydia who were referred to the health adviser as per clinic protocol, were offered CS2. For 3 months, starting in February, the number of contact attendances at MMC or elsewhere for each index patient was recorded.

For both cohorts, as well as recording the number of attendances verified as attending at both MMC and other GUM clinics, patients reporting partner attendance at other GUM clinics without the details required for verification (no surname, no date of birth, partner using a pseudonym, etc) were also recorded. Refusal of either contact slip was documented. Provision of care was otherwise identical, regardless of which contact slip, if any, was issued.

It was determined that in order to detect a 20% increase in number of contacts treated, with 90% power, each cohort needed to comprise at least 110 patients. The χ² test was used to compare proportions between the two time periods.

RESULTS

In all, 136 and 133 patients, respectively, were eligible during each study period (table 1). A significantly higher proportion of patients was not given contact slips during the first period. The reasons are listed in table 2.

The number of refusals was similar in both cohorts (one in each).

The mean number of contact slips issued per patient was not different between the two groups (table 1).

The number of contacts attending per contact slip issued, and per index patient, was significantly higher with CS2 (table 1).

The proportion of contacts confirmed as, or merely reported to have been, treated elsewhere was similar in both groups (table 3).

DISCUSSION

The aim of partner notification is to break the chain of transmission of STIs and reduce the national rates of infections through identifying, counselling, and screening sexual partners/contacts of index patients and offering treatment if appropriate.⁴

The CS1 was designed to achieve this aim, as well as preserve the confidential diagnosis of the index patient through the use of a code in place of the name of the STI with which the index case has been diagnosed. In addition, use of CS1 provides an acceptable means of identifying the potential infection to the clinic attended by the contact.

The first aim of this study was to determine whether identifying the infection on the contact slip would be less acceptable to the index patient. In the case of chlamydia infections in heterosexual patients, a contact slip naming the infection appears to be equally acceptable.

CS2 was significantly more effective as a means of encouraging sexual contacts to attend for screening and treatment. CS1 achieved only a 45% rate of one or more contact attendance per index patient, less than the 70% minimum standard as documented in The Clinical Management of Genital Chlamydia Infection.⁵ CS2, however, resulted in 89% rate of one or more contact attendance. CS2 also surpassed the standard of at least one contact per index patient attending,⁵ whereas CS1 achieved only half of this target.

The study was not randomised, nor could it be blinded and there is, therefore, potential for bias. Staff may have been more enthusiastic about partner notification when using the new contact slip. There is some evidence for this as more patients were seen by a health adviser and therefore more patients received contact slips in the second study period. However, since more index patients were seen by health advisers in the second time period, it might be expected that this included more patients who were more reluctant to engage in partner notification. The number of contact slips issued per index patient seen remained the same, but the number of contacts attending per index patient increased, suggesting that the increase was due to the contact slip itself.

Health advisers may have more readily accepted that partner notification had been resolved in the second half of the study, but as every set of notes was reviewed by AW this was minimised. Furthermore, partner notification resolution was recorded on a specific proforma and there was no evidence of a higher proportion of “reported” as opposed to “confirmed” contacts treated, as shown in table 3.

Other clinics may have been more likely to return the new contact slip to the issuing clinic, leading to an apparently higher partner notification resolution rate for CS2. However, there is no evidence that a higher proportion of cases were treated elsewhere during the second part of the study (table 3).

Contacts from the CS2 cohort may have been encouraged to attend by the high profile health education awareness programmes in the media about chlamydia, and its potential long term sequelae, which began in 2000. Contacts, having been made aware of their potential risk of contracting chlamydia, may have found these programmes to be a catalyst in determining whether to attend for treatment.

Other studies have looked at ways of increasing the success of partner notification by using financial incentives or health education materials⁶ and by pre-booking contacts’ appointments.⁷ Only verbally delivered health education appeared to be effective in randomised controlled trials. Several of these studies used contact slips (or referral cards) but none has examined the content of these slips. Most studies of contact tracing have used “numbers of contacts traced” as the outcome measure, as we did in this study. It has been suggested that numbers of infected contacts is a better measure⁶ but van de Laar et al⁸ have shown high rates of infection among traced contacts.

Further study of the use of such contact slips in other settings will provide information about the repeatability and generalisability of these findings. Studies focusing on other infections and other population groups will also be required.