Methods

A retrospective analysis was conducted to evaluate changes and compare testing and infections detected before and after the staggered introduction of STI POC testing (Cepheid GeneXpert®) during the TTANGO2 program (2016-2019), for chlamydia/gonorrhoea and trichomonas tests. https://www.ttango.com.au Data included routine tests (laboratory or POC) from 20 primary care clinics (18 remote, 2 regional) among Aboriginal and Torres Strait Islander people aged 15-54. Clinics’ POC introduction dates were aligned to a common intervention point and mean monthly tests and infections detected were calculated for all clinics 9-months before and 15-months after POC introduction. Interrupted time series analysis evaluated changes at the intervention point (immediate) and trends over the follow-up period (sustained), while linear regression compared the before and after periods. Changes and comparisons in concurrent syphilis and HIV testing were also assessed.

 

Results*

When STI POC testing was introduced, there was an immediate, large increase of 26% in chlamydia/gonorrhoea tests and 21% in trichomonas tests; this increased testing level was sustained in the 15-month follow-up period. There was an overall increase in mean monthly tests for chlamydia/gonorrhoea (15%) and trichomonas (30%) compared with the before period. When STI POC testing was introduced, there was an immediate, large increase in infections detected; 30% for gonorrhoea and 29% for trichomonas; and a modest increase for chlamydia, 9%(non-significant). The increased detection of gonorrhoea and trichomonas infections was not sustained over the 15-month follow-up period. There was a modest increase (non-significant) in mean monthly infections detected: chlamydia (10%), gonorrhoea (12%) and trichomonas (13%) compared with the before period.

 

The introduction of STI POC testing did not decrease syphilis and HIV testing rates. Patterns of concurrent chlamydia/gonorrhoea tests with syphilis and HIV testing were consistent with those described above. Additionally, an analysis of the proportion of syphilis tests conducted for chlamydia/gonorrhoea tests showed no immediate change when STI POC testing was introduced (-1.6%, non-significant). There was a modest non-significant 4% increase in the proportion of syphilis tests. However, there was an immediate 25% increase in the proportion of syphilis tests conducted for chlamydia or gonorrhoea infections when STI POC testing was introduced, which was sustained in the follow-up period. Overall, the proportion of syphilis tests conducted for chlamydia/gonorrhoea infections increased by 14% (near significance, p=0.058) compared to the before period.

 

* All results presented are statistically significant at p<0.05, unless stated otherwise.

 

Conclusion

This analysis uniquely demonstrated that the introduction of molecular STI POC testing led to increased STI testing and early detection of infections in regional and remote primary care clinics where laboratory testing was already available. These increases occurred immediately after the introduction of POC and were sustained for testing throughout the follow-up period. The additional diagnoses, and more timely treatment following the introduction of STI POC testing likely contributed to a reduction of onward transmission and sequelae of infections, such as pelvic inflammatory disease. To optimise these benefits, primary care services should be supported to ensure greater uptake of molecular POC testing.