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

 
Informing Low-acuity Emergency Department Patients of Non-emergent Healthcare 
Resources Following Discharge to Decrease Emergency Department Utilization 
(NCT 06350266) 
 
Study Protocol with Statistical Analysis Plan 
 
 
July 25, 2024 
 
 
 
 

 
Study Protocol 
 
Background 
 
The goal of this campaign is to reduce unnecessary emergency department (ED) 
visits/encourage patients with low acuity visits to follow up with an appropriate provider and/or to 
seek care outside of the ED in the future. In this campaign, patients will be assigned to receive 
or not receive outreach following ED discharge that is aligned with the goal. Outreach will occur 
via a text message, as well as information added to the patient's after visit summary (AVS), and 
will include one or more calls to action that make patients aware of other Geisinger resources 
and avenues through which they can seek care outside of the ED. These may include, but are 
not limited to, walk-in urgent care, virtual urgent care, primary care provider (PCP) 
appointments, and/or other ways in which to contact Geisinger. The study will assess whether 
ED use differs across patients in different outreach conditions. It will also examine whether 
patients followed through on the message-specific calls to action in the messages differently 
across conditions. 
 
Objectives 
 
The study will involve randomized assignment of patients to different versions of outreach, 
including a treatment arm that encourages patients in non-emergent situations to call their 
primary care provider’s office first and, if unavailable, to try urgent care (or other options, as 
described next).  Patients with a Geisinger PCP are also provided with the appropriate contact 
number for their PCP, given hyperlinks to Geisinger’s urgent care website, and encouraged to 
consider other same-day care options via a hyperlink to Geisinger’s corresponding website.  
Patients without a Geisinger PCP are encouraged to consider Geisinger’s virtual (telehealth) 
care, with a corresponding hyperlink.  Both SMS text messages (at 1 day, 22 days, and 50 days 
post-discharge) and AVS (printed or available via patient portal upon discharge) will be used for 
active outreach.  The control arm will receive the current standard system outreach and 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 two study arms. Patients will be randomized to 
receive or not receive SMS texts and a modified AVS 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 AVS and whatever typical system outreach occurs. 
2. Same-day care alternatives (treatment arm):  Patients in this arm will receive 
suggestions for non-ED alternatives for same-day care. 
a. Those with a Geisinger PCP will also be provided with: 
i. 
PCP contact number 
ii. 
Hyperlink to Geisinger’s urgent care website 
iii. 
Hyperlink to Geisinger website detailing same-day care options 

 
b. Those without a Geisinger PCP will also be provided with a hyperlink to 
Geisinger’s virtual care option. 
 
Power Analysis 
 
With 5,524 patients, we would have 80% power to detect a 3.0% absolute decrease in ED visits 
between active and control 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 25, 2024, but no data have been analyzed as of the time this 
document was uploaded. 
 
Patients without GHP insurance who received or would have received their first message 
between 5/14/24 and 6/6/24 (N = 662) will be removed from the analysis due to unexpected 
message filtering and restrictions imposed by one of the cell service carriers.  
 
Because of the unforeseen analysis exclusions, we will collect data from an additional 662 
patients. Our updated target sample size is 6,186. 
 
Statistical Analysis Plan 
 
Planned Analyses 
 
Primary Outcome: ED visit [Time Frame: within 120 days following day of discharge] 
 
Question: Does outreach decrease ED visits when including information about same-day 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 = treatment arm).  
 
Other Pre-specified Outcomes 
 
We will run the analysis described above on the following additional outcomes: 
 
1. PCP appointment scheduled 
 
PCP appointment scheduled (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 scheduled 
 
Telehealth appointment scheduled (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. Any of the suggested actions taken 
 
PCP called or visited, urgent care visited, telehealth appointment attended, or PCP or 
telehealth appointment scheduled (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).  
 
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