Point of ED Discharge Interactive Outreach: High ED Utilizers
Phase: NA
Conditions: Emergency Service, Hospital
Sponsor: Geisinger Clinic

 
Nudging High Emergency Department Utilizers to Consider Non-emergent Healthcare 
Resources  
(NCT) 
 
Study Protocol with Statistical Analysis Plan 
 
 
January 29, 2025 
 
 
 
 

 
Study Protocol 
 
Background 
 
The goal of this campaign is to reduce unnecessary emergency department (ED) 
visits/encourage patients who have visited a Geisinger Emergency Department four (4) 
or more times within the last 6 months to seek care through alternatives to ED use when 
appropriate. In this campaign, patients will receive outreach aligned with this goal 
following ED discharge and will be assigned to outreach via an interactive chatbot 
message or a live phone call from a Community Health Worker (CHW) or Certified 
Medical Assistant (CMA).  
 
The study will assess whether ED use differs across patients in different outreach 
conditions. 
 
Design  
 
This study is a randomized controlled trial with two study arms. Patients will be 
randomized to receive (1) a call from a CHW or CMA or (2) a message from an 
interactive Artera chatbot upon ED discharge. 
 
Methods 
 
At the time of an eligible patient’s discharge from the ED, that patient will be assigned to 
one of the following study arms, based on which of several ranges of randomized 
numbers that patient was originally assigned in their electronic chart: 
 
1. Current standard practice (control arm): Patients in this arm will receive the 
current standard system outreach (i.e., call from CHW or CMA). 
2. Interactive chatbot outreach (treatment arm): Patients in this arm will receive 
outreach from an interactive chatbot. 
 
Power Analysis 
 
The power calculation has been modified from the original estimation, given less-than-
expected eligible patients over time. With 2,279 patients, we would have 80% power to 
detect a 5.0% absolute decrease in ED visits between the active arm and the control 
arm, with two-tailed alpha of .15, assuming a 50% baseline rate of subsequent ED visits 
within 120 days. The target effect size and number of patients are largely informed by 
practical considerations regarding the acceptable duration of the intervention (maximum 
of 7 months, regardless of whether the full sample is achieved), with an effect deemed 
useful if achieved. 
 
 
 
 

 
Project Status 
 
The intervention has not yet begun. 
 
Statistical Analysis Plan 
 
Planned Analyses 
 
Primary Outcome: ED use [Time Frame: within 120 days following day of discharge] 
 
Question: Does outreach decrease ED visits when including an automated text chatbot 
instead of live outreach? 
 
Analysis (Confirmatory): We will test the hypothesis that outreach from an interactive 
chatbot versus a CHW or CMA decreases the likelihood patients will visit the ED in the 
120 days following day of discharge.  We will run an OLS regression including a 
categorical predictor variable coding for experimental arm (0 = control arm, 1 = 
treatment arm).  
 
Other Pre-specified Outcomes 
 
We will run the analysis described above on the following additional outcomes: 
 
1. Contact with patient by monitoring center, CMA, or CHW 
 
Contact with patient by monitoring center, CMA, or CHW (yes/no) 
 
[Time Frame: within 3 business days following day of discharge] 
 
2. Contact with patient by monitoring center, CMA, or CHW 
 
Contact with patient by monitoring center, CMA, or CHW (yes/no) 
 
[Time Frame: within 5 business days following day of discharge] 
 
3. Time to successful contact by monitoring center, CMA, or CHW 
 
Number of business days to successful contact by monitoring center, CMA, or 
CHW  
 
4. Interaction of patient with Artera chatbot 
 
Interaction of patient with Artera chatbot (yes/no) 
 
[Time Frame: within 7 calendar days following first Artera outreach] 
 

 
5. ED use 
 
ED use (yes/no) 
 
[Time Frame: within 30 days following day of discharge] 
 
6. ED use 
 
ED use (yes/no) 
 
[Time Frame: within 30 days following day of outreach by Artera or CMA/CHW] 
 
 
Analysis Notes 
 
Recent work suggests that OLS regressions are appropriate in randomized experiments 
with binary outcome variables such as ours (Gomila, 2021).  
 
Reference 
 
Gomila, R. (2021). Logistic or linear? Estimating causal effects of experimental 
treatments on binary outcomes using regression analysis. Journal of Experimental 
Psychology: General, 150(4), 700-709. https://doi.org/10.1037/xge0000920