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Impact of provincially-funded non-invasive prenatal testing on the utilization of invasive diagnostic testing in British Columbia Chu, Scally Wei-Lin


Introduction: Non-invasive prenatal testing (NIPT) is an accurate and safe screening test for detection of Down syndrome, trisomy 18, and trisomy 13, which can be used to reduce the need for invasive diagnostic testing in high-risk women. In November 2015, British Columba (BC) introduced publicly-funded NIPT as a contingent screening test for women at an increased risk of having a trisomic pregnancy. The objective of this research was to quantify the extent to which the introduction of publicly-funded NIPT influenced the utilization of invasive diagnostic testing in BC. Methods: We used linked population-based provincial prenatal biochemistry and cytogenetic laboratories data maintained by the BC Prenatal Genetic Screening Program and Perinatal Services BC. Our study population included all known singleton pregnancies in BC between April 1, 2011 and April 30, 2017 with a positive result from provincially-funded serum integrated prenatal screen (SIPS), integrated prenatal screen (IPS), and quad marker screen (Quad). We divided this timeframe into three periods: period 1 with no NIPT (April 1, 2011-January 31, 2013), period 2 with self-pay NIPT only (February 1, 2013-October 31, 2015), and period 3 with publicly-funded NIPT (November 1, 2015-April 30, 2017). We performed an interrupted time series analysis using log-binomial regression to evaluate the change in use of invasive diagnostic testing after the introduction of self-pay NIPT and publicly-funded NIPT. Models were adjusted for maternal age and self-reported maternal race. Results: Among the 8,649 pregnancies included in the study, the estimated rate of invasive diagnostic testing decreased by 12.7% (95% CI: 0.79 to 0.97) when self-pay NIPT was introduced. With the introduction of publicly-funded NIPT, the estimated rate of invasive diagnostic testing decreased by 47.8% (95% CI: 0.40 to 0.68). The estimated trend of decrease in the rate of invasive diagnostic testing utilization was 1.7% per month (95% CI: 0.98 to 0.99) within the second period with self-pay NIPT. Conclusions: The introduction of publicly-funded NIPT was associated with a significant decrease in the number of invasive diagnostic tests performed in BC among singleton pregnancies screened positive with provincially-funded SIPS, IPS, and Quad. Future cost-consequences studies including detailed healthcare costs would be valuable.

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