Informing Low-acuity Emergency Department Patients of Non-emergent Healthcare Resources Following Discharge to Decrease Emergency Department Utilization (2)
Phase: NA
Conditions: Emergency Service, Hospital, Behavior Change Interventions
Sponsor: Geisinger Clinic

 
Informing Low-acuity Emergency Department Patients of Non-emergent Healthcare 
Resources Following Discharge to Decrease Emergency Department Utilization Part 2 
(NCT to be assigned) 
 
Study Protocol with Statistical Analysis Plan 
 
 
September 15, 2025 
 
 
 
 

 
Study Protocol 
 
Background 
 
The goal of this campaign is to reduce unnecessary visits to a Geisinger emergency department 
(ED). In this campaign, patients will be assigned to receive or not receive outreach following ED 
discharge with a low-acuity visit designation. Outreach will occur via a text message the day 
after discharge from the ED as well as information added to the patient's after visit summary 
(AVS). Depending on the assigned condition, it will include calls to see their primary care 
provider (PCP) or use an Intelligent Triage tool. The study will assess whether ED use within the 
following 120 days differs across patients in different outreach conditions (current standard 
practice vs contact your PCP vs use Intelligent Triage). It will also examine whether patients 
follow through on the message-specific calls to action differently across conditions. 
 
Objectives 
 
The study will involve randomized assignment of patients to different versions of outreach. 
Intervention arms will either encourage patients in non-emergent situations to contact their 
primary care provider, or to use an Intelligent Triage tool to help determine the best venue for 
their care. The control arm will receive the current standard system AVS. Data will be analyzed 
to determine which version is most effective at reducing ED use. 
 
Design  
 
This study is a randomized controlled trial with three study arms. Patients will be randomized to 
one of the three conditions: (1) current standard practice (2) contact your PCP (3) use Intelligent 
Triage. 
 
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 AVS and whatever typical system outreach occurs 
2. Contact your PCP (treatment arm):  Intervention content emphasizes contacting a 
primary care provider (content will vary slightly based on whether the patient has a 
Geisinger PCP) 
3. Use Intelligent Triage (treatment arm): Intervention content emphasizes using 
Intelligent Triage to assess symptoms and decide on an appropriate venue for care 
 
Power Analysis 
 
With 8,286 patients (2,762 per arm), we would have 80% power to detect a 3.0% absolute 
decrease in ED visits between any two arms, with two-tailed alpha of .15, assuming a 41% 
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 (approximately 6 months), with an effect deemed useful if achieved. 
 
 

 
Project Status 
 
The intervention launched on April 15, 2025, but no data have been extracted from the 
electronic health record or analyzed as of the time this document was uploaded. 
 
Statistical Analysis Plan 
 
Planned Analyses 
 
Primary Outcome: ED visit [Time Frame: within 120 days following day of discharge] 
 
Question: Do the active treatment conditions decrease ED visits compared with standard care? 
 
Analysis (Confirmatory): We will test the hypothesis that SMS text plus AVS outreach 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 = Contact your PCP, 2 = Use Intelligent Triage).  
 
Question: Are messages encouraging patients to contact their PCP or encouraging the use of 
Intelligent Triage differently effective at decreasing ED use?  
 
Analysis (Exploratory): We will test the hypothesis that SMS text plus AVS outreach is different 
in the Contact your PCP arm and Use Intelligent Triage arms. We will run an OLS regression 
including a categorical predictor variable coding for experimental arm (0 = Contact your PCP, 1 
= Use Intelligent Triage).  
 
Other Pre-specified Outcomes 
 
We will run the analysis described above on the following additional outcomes: 
 
1. PCP appointment made 
 
PCP appointment made (yes/no) 
 
[Time Frame: within 60 days following day of discharge] 
 
2. PCP visit 
 
PCP appointment attended (yes/no) 
 
[Time Frame: within 60 days following day of discharge] 
 
3. Telehealth appointment made 
 
Telehealth appointment made (yes/no) 
 
[Time Frame: within 60 days following day of discharge] 
 

 
4. Telehealth appointment attended 
 
Telehealth appointment attended (yes/no) 
 
[Time Frame: within 60 days following day of discharge] 
 
5. Urgent care visit 
 
Urgent care appointment attended (yes/no) 
 
[Time Frame: within 60 days following day of discharge] 
 
6. Call made to PCP 
 
Record of patient call to PCP (yes/no) 
 
[Time Frame: within 60 days following day of discharge] 
 
7. Used Intelligent Triage tool 
 
Used Intelligent Triage tool (yes/no) 
 
[Time Frame: within 60 days following day of discharge] 
 
8. Any of the suggested actions taken 
 
PCP called or visited, urgent care visited, telehealth appointment attended, or PCP or 
telehealth appointment scheduled, or used Intelligent Triage (yes/no) 
 
[Time Frame: within 60 days following day of discharge] 
 
Analysis Notes 
 
Recent work suggests that OLS regressions are appropriate in randomized experiments with 
binary outcome variables such as ours (Gomila, 2021). We will report heterogeneity-robust 
standard errors. 
 
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