Analysis
The primary analysis was to assess whether the telemedicine-hybrid care model was non-inferior to the traditional service model. Non-inferiority is established by comparing effectiveness and safety in the two cohorts under the null hypothesis that the rates of successful abortion and serious adverse events are not different.
We first compared patient demographic and clinical characteristics between the cohorts to assess the need to covariate-adjust our hypothesis tests for systematic differences in the two groups that might affect abortion outcomes. All hypothesis tests were covariate adjusted for patient age, race/ethnicity, gestational age, parity, and prior abortions using logistic regression and weighted risk differences.(20)
We evaluated effectiveness by testing the alternative hypothesis that the rate of successful medical abortion in the telemedicine-hybrid cohort is lower than in the traditional cohort using a covariate-adjusted test of difference in proportions. We also performed a chi-squared test to evaluate whether the distribution of unsuccessful abortion sub-categories differed between the cohorts. We evaluated safety by testing the alternative hypothesis that significant adverse events occurred at higher rates in the telemedicine-hybrid cohort compared to the traditional cohort using a covariate-adjusted hypothesis test for difference of proportions. We also evaluated whether the prevalence of ectopic pregnancies managed before EMA and after EMA were different between the traditional and telemedicine-hybrid cohorts using chi-squared difference of proportions tests.
The secondary analysis was to compare effectiveness and safety of medical abortion for patients who received fully remote no-test telemedicine vs. in-person care in the telemedicine-hybrid cohort, primarily to assess whether any differences between the cohort service models were driven by one particular group. We evaluated patient demographic and clinical characteristic differences between the two groups to assess the need to covariate-adjust our hypothesis tests for systematic differences and all hypothesis tests were covariate adjusted for patient age, race/ethnicity, gestational age, parity, and prior abortions using the framework described above. We note, however, that these cohorts are fundamentally different despite covariate adjustment, as patients in the telemedicine-hybrid cohort were selected into in-person treatment based on characteristics that would affect the outcome of their abortion. We performed covariate-adjusted hypothesis tests under the null hypothesis of equal effectiveness and equal rates of significant adverse events in the telemedicine vs. in-person groups.
All analyses were performed using R, version 3.6.2. Statistical significance was defined using an alpha level of 0.05.