Statistical analysis
tooth
REGRESSION
A priori power analyses were based on 2018 data from HealthPartners and estimated 6900 patients ages 16 and older receiving extractions in each of the baseline and intervention periods seen by 51 providers (slightly more than the final analysis sample). In 2018, 40% of tooth extraction encounters included an opioid prescription, and the provider-level intraclass correlation for opioid prescribing was estimated at 0.3. Under these assumptions about HealthPartners providers and patients, and Data were analyzed using generalized linear mixed models for binary data (binomial family with logit link function; alternatively known as mixed effects logistic regression). The dependent variable was extraction-level opioid prescription (no vs. yes). Explanatory variables include Time (baseline vs. intervention), Arm (CDS vs. CDS-E vs. SP), and the Arm × Time interaction (representing the effect of interest). Analyses were adjusted for patient sex and age, extraction complexity (simple vs. complex), and baseline prescribing strata (dentist vs. oral surgeon; baseline opioid prescribing volume). Models included a random intercept for provider to account for the cluster design. Comparisons were made from the baseline to the intervention period within each study arm, while the primary effect of interest was examined as the differential change between CDS and CDS-E arms in comparison to the SP arm. Contrasts of interest were examined using odds ratios, model-based predicted probabilities, and their confidence intervals (95% confidence intervals for baseline vs. intervention period comparisons within study arm; 97.5% confidence intervals for comparing each of the two intervention arms against SP with respect to differential change. The 97.5% confidence interval was used for the primary endpoint in order to address multiple comparisons across three study arms). Analyses were conducted on an intent-to-treat basis. To give additional context for the findings, utilization of the CDS was examined descriptively.In addition to the primary analysis, post hoc analyses were conducted excluding oral surgeons (due to their having more opioid prescriptions and lower utilization of the CDS). The association between providers’ CDS utilization and opioid prescribing at the extraction visit was examined among providers in the CDS and CDS-E arms (i.e., those who had the opportunity to use the CDS). These post hoc analyses were conducted using a similar analytical strategy as used for the primary analysis, except that it excluded oral surgeons due to their minimal utilization of the CDS and included an interaction term between extraction complexity and CDS utilization.