Dual Intervention to Increase Chlamydia Retesting: A Randomized Controlled Trial in Three Populations

Chlamydia retesting is recommended three months after treatment to identify reinfections. However, retesting rates remain low across multiple populations. Prior research has shown that SMS reminders can encourage retesting, but their effectiveness is limited. No prior work had resolved whether combining SMS with home testing kits improves retesting rates. This gap motivated the current study to explore if adding a home collection kit to SMS reminders increases retesting rates. Established knowledge includes the role of SMS in health reminders and the challenges of clinic-based retesting. This paper's contribution is to test a novel intervention combining SMS and home testing. The study addresses a key limitation in current retesting strategies. It also considers differences across three risk groups. The findings may inform future public health approaches.

The study aimed to determine if adding a postal home collection kit to SMS reminders increases chlamydia retesting rates. It focused on three populations: women, heterosexual men, and men who have sex with men. The intervention involved SMS plus home testing kits, compared to SMS alone. The goal was to assess whether this combination improves retesting rates. The study also sought to evaluate detection of repeat positive tests. The design was a randomized controlled trial. Participants were diagnosed and treated for chlamydia at sexual health services. The study tested the effectiveness of a dual intervention approach.

Participants were randomized 1:1 to either the home arm or clinic arm. The home arm received an SMS reminder and a postal home collection kit. The clinic arm received only an SMS reminder. The home arm used different swabs depending on the population. Women received vaginal swabs, heterosexual men received UriSwab, and men who have sex with men received UriSwab and rectal swab. The main outcome was retesting rates at 1-4 months after diagnosis. The study also measured the percentage of repeat positive tests. Data collection occurred from 2011 to 2013, with analysis in 2014. The study used an intention-to-treat analysis to compare outcomes between arms.

The home arm had significantly higher retesting rates than the clinic arm across all groups. For women, 64% retested versus 39% in the clinic arm (p<0.001). For heterosexual men, 56% retested versus 34% (p=0.002). For men who have sex with men, 62% retested versus 44% (p=0.010). Overall, 61% in the home arm retested versus 39% in the clinic arm (p<0.001). Repeat positive tests were also higher in the home arm. Among men who have sex with men, 16% had repeat positives versus 5% in the clinic arm (p=0.021). Overall, 10% in the home arm had repeat positives versus 4% in the clinic arm (p=0.006). These results suggest the dual intervention improved both retesting and detection of reinfections.

The addition of a postal home collection kit to SMS reminders significantly increased retesting rates across all three groups. The home arm had higher retesting rates for women, heterosexual men, and men who have sex with men. The study also found more repeat positive tests in the home arm. These findings suggest that combining SMS with home testing improves adherence to retesting guidelines. The authors propose that extending this approach to other settings may be beneficial. No prior work had resolved whether home testing improves retesting rates. The study highlights the potential of dual interventions in public health. The authors suggest considering this approach in primary care settings with low retesting rates.