Abstract
Background Clinical prediction rules (CPRs) can be used in sexually transmitted infection (STI) testing environments to prioritize individuals at the highest risk of infection and optimize resource allocation. We previously derived a CPR to predict asymptomatic chlamydia and/or gonorrhea (CT/NG) infection among women and heterosexual men at in-person STI clinics based on 5 predictors. Population differences between clinic-based and Internet-based testers may limit the tool's application across settings. The primary objective of this study was to assess the validity, sensitivity, and overall performance of this CPR within an Internet-based testing environment (GetCheckedOnline.com). Methods We analyzed GetCheckedOnline online risk assessment and laboratory data from October 2015 to June 2019. We compared the STI clinic population used for CPR derivation (data previously published) and the GetCheckedOnline validation population using χ2 tests. Calibration and discrimination were assessed using the Hosmer-Lemeshow goodness-of-fit test and the area under the receiver operating curve, respectively. Sensitivity and the fraction of total screening tests offered were quantified for CPR-predicted risk scores. Results Asymptomatic CT/NG infection prevalence in the GetCheckedOnline population (n = 5478) was higher than in the STI clinic population (n = 10,437; 2.4% vs. 1.8%, P = 0.007). When applied to GetCheckedOnline, the CPR had reasonable calibration (Hosmer-Lemeshow, P = 0.90) and discrimination (area under the receiver operating characteristic, 0.64). By screening only individuals with total risk scores ≥4, we would detect 97% of infections and reduce screening by 14%. Conclusions The application of an existing CPR to detect asymptomatic CT/NG infection is valid within an Internet-based STI testing environment. Clinical prediction rules applied online can reduce unnecessary STI testing and optimize resource allocation within publicly funded health systems.
Original language | English |
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Pages (from-to) | 481-487 |
Number of pages | 7 |
Journal | Sexually Transmitted Diseases |
Volume | 48 |
Issue number | 7 |
DOIs | |
Publication status | Published - 1 Jul 2021 |
Funding
Conflict of Interest and Sources of Funding: This study was funded by the Canadian Institutes of Health Research (CIHR) Team Grant: HIV Implementation Science—Component 2 Grant (CTW-155387). A.A. and O.G.-R. report the aforementioned grants from the Canadian Institutes of Health Research, and O.G.-R. reports postdoctoral funding from the Canadian HIV Trials Network and postdoctoral funding from Michael Smith Foundation for Health Research during the conduct of the study.
Keywords
- asymptomatic chlamydia
- asymptomatic gonorrhea
- clinical prediction rules (CPRs)
- sexually transmitted infection (STI)
- resource allocation
- publicly funded health systems