Rationale and background
Globally, sexually transmitted infections (STIs) constitute a major public health concern, with more than one million acquired every day. In Catalonia, as also seen in Spain and Europe more broadly, rates of STIs have been increasing in recent years. In addition, the COVID-19 pandemic led to significant disruptions in sexual health services, which may have exacerbated existing barriers to health service access, particularly for those who were less engaged with the health service prior to COVID-19. Given the higher rates of STIs reported as well as the barriers migrants may face in accessing sexual health services, migrants comprise an important population for STI prevention and response. However, there is significant diversity among migrants as a group. In order to target interventions, it is crucial to better understand the characteristics of migrants most at risk of STIs as well as the impact of COVID-19 disruptions on access to and uptake of sexual health services.
Objectives
The aim of this study is to estimate time trends in the incidence and prevalence of sexually transmitted infections, including Chlamydia, Gonorrhoea, Syphilis, Trichomoniasis, Genital herpes, Mpox and HPV, in Spanish and non-Spanish primary care users in Catalonia and identify changes in key population groups at risk over time.
This aim will be addressed through three objectives:
1.Characterise Spanish and non-Spanish primary care users in Catalonia in terms of sex, age, socioeconomic status, geographic location, and country of origin.
2.Investigate the incidence and prevalence of STIs in Spanish and non-Spanish individuals by sex, age, socioeconomic status, geographic location and country of origin.
3.Explore the impact of COVID-19-related disruptions on access to sexual health services and STI positivity among migrants and non-migrants.
Methods
Study design
This study is a population-based observational cohort study using individual-level routinely collected Electronic Health Records from the SIDIAP database
Population
The study population will include all patients registered with primary care in Catalonia, with a recorded nationality, diagnosed with any of the following STIs, including chlamydia, syphilis, gonorrhoea, trichomoniasis, HPV, genital herpes, and mpox, from 1st January 2006 to end of data availability. Patients will need to have at least 365 days of data visibility prior to index date.
Variables
Primary outcome: diagnosis of STI including chlamydia, syphilis, gonorrhoea, trichomoniasis, human papillomavirus (HPV), genital herpes, and mpox.
Secondary outcomes: visits to sexual health services and uptake of HPV vaccination.
Relevant covariates: sex, age, socioeconomic deprivation, geographic location and region of origin.
Data Source
The Information System for Research on Primary Care (SIDIAP), Spain
Statistical analysis
We will firstly characterise participants in terms of nationality (Spanish vs. non-Spanish), sex, age, socioeconomic status, geographic area, and region of origin (in the case of non-Spanish individuals) at their index date. Then we will summarise incidence and prevalence rates by infection and overall by nationality (Spanish vs. non-Spanish) and calculate relative risks adjusted by sex, age and socioeconomic status. Lastly, we will conduct an interrupted time series analysis of the impact of COVID-19-related health service disruptions on access to STI services and diagnosis for migrants and non-migrants.
The statistical analyses will be performed based on OMOP-CDM mapped data using OHDSI R packages. A minimum cell counts of 5 will be used when reporting results, with any smaller count reported as <5.