Nurse Follow-up to Reduce Inappropriate Emergency Department Utilization in Adult Patients Seen for Ambulatory Sensitive Conditions in CMSL
Phase: NA
Conditions: Behavioral Intervention, Emergency Department Visits, Nurse Care Coordination
Sponsor: Geisinger Clinic

 
CMSL Ambulatory Sensitive Condition Nudge  
(pending) 
 
Study Protocol with Statistical Analysis Plan 
 
 
January 24, 2025 
 
 
 
 

 
Study Protocol 
 
Background and Objective 
 
The project aims to evaluate a nurse-led intervention to reduce inappropriate emergency 
department (ED) use among adult patients seen at Geisinger's Community Medicine Service 
Line (CMSL) clinics. The intervention occurs immediately following an appointment where a 
patient receives a diagnosis of an ambulatory sensitive condition (ASC; i.e., a condition 
considered to be a risk factor for near-term ED use). The evaluation will compare eligible 
patients with an ASC who were randomly assigned to receive follow-up outreach from a nurse 
(who was automatically prompted via the Epic electronic health record system to initiate 
outreach) with those who were randomly assigned to receive standard care. Analyses will be 
intent-to-treat. The primary outcome is ED use in the week following the appointment. 
 
Objectives 
 
The study will evaluate an intervention aimed at reducing ED use following ASC diagnoses via 
nurse post-appointment calls. Analyses will assess whether ED use is lower in the patients 
receiving the intervention vs. those in the control arm. 
 
Design  
 
This study is a randomized controlled trial with two study arms. Patients will be randomized to 
have their nurses receive or not receive outreach via Epic (the night following their 
appointment). 
 
Methods 
 
At the end of an eligible patient’s CMSL appointment, a 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: 
 
Current standard practice (control arm): Patients will not be included in a nurse 
follow-up call list.  
 
Nurse nudge: Following their visit and ASC diagnosis, patients in this arm will be  
included on an automated list for a nurse follow-up call. Note that, although the nurses  
will be prompted to call, not all patients in this arm will receive a call.  
 
Power Analysis 
 
With 2,988 patients, we would have 80% power to detect a 1.2% absolute decrease in ED visits 
between the active arm and the control arm, with two-tailed alpha of .05, assuming a 2% 
baseline rate of subsequent ED visits within 7 days. The target effect size and baseline rate 
were taken from a similar intervention on a separate service line at Geisinger. 
 
Project Status 
 
The intervention began on 1/6/2025. No data have been extracted from the electronic health 
record. 
 

 
Statistical Analysis Plan 
 
Planned Analyses 
 
Primary Outcome: ED visit [Time Frame: within 7 days post-appointment] 
 
Question: Does outreach decrease ED visits? 
 
Analysis (Confirmatory): We will test the hypothesis that automatic Epic notification decreases 
the likelihood patients will visit the ED in the 7 days following the day of their appointment.  We 
will run an OLS regression including a categorical predictor variable coding for experimental arm 
(0 = control arm, 1 = outreach arm).  
 
 
Other pre-specified outcome: Nurse call to patient [Time frame: within 7 days post-
appointment] 
 
Question: Does the nurse nudge increase post-appointment nurse calls to patients? 
 
Analysis (Confirmatory): We will test the hypothesis that automatic Epic notification increases 
the likelihood that nurses will call patients in the 7 days following the day of their appointment. 
We will run an OLS regression including a categorical predictor variable coding for experimental 
arm (0 = control arm, 1 = outreach arm). 
 
 
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