Nudging myGeisinger Enrollment Using Timely Email Messaging Reminding Patients of Lab Results Available
Phase: NA
Conditions: Telehealth, Health Behavior
Sponsor: Geisinger Clinic

Nudging myGeisinger Enrollment Using Timely Email Messaging Reminding Patients of Lab 
Results Available 
 
NCT04333199 
 
April 7, 2021 
 
 

Study Protocol 
 
Purpose 
The purpose of the current study is to test whether sending email communications in a timely 
manner - when patients have laboratory results available to view on the myGeisinger patient 
portal - increases enrollment in the portal. Secondarily, this study A/B tested 2 different 
versions of the timely email. 
 
Method 
 
Sample 
The study population consisted of patients aged 18 or older who were not yet enrolled in 
myGeisinger, who had an email address on file, for whom a lab or test was ordered within 30 
days prior to the email date, and whose lab or test result was released to myGeisinger the day 
before the email date. Patients who had declined enrollment in myGeisinger were excluded 
from the study. 
Based on the above criteria, N = 5,012 patients were randomized to a study condition 
and sent an email between May 18, 2020 and June 1, 2020 (15 days). Patients who had multiple 
lab/test results in this period were only randomized to a study condition once, upon their first 
qualifying result, and did not receive more than one email. Electronic Health Records (EHR) for 
study patients were subsequently examined to evaluate portal enrollment; records for 3 
patients were no longer present in the EHR, leaving a total of N = 5,009 patients for analysis. All 
comparisons between patients emailed and those not contacted were conducted within this 
total. 
Within the analyzed sample, 3,340 patients were allocated to an email condition. Of 
these, 404 were flagged by the email delivery software as invalid email addresses and were 
thus not sent an email. Subsequently, an additional 186 emails bounced, leaving a total of N = 
2,750 emails delivered. All comparisons between the two email conditions were conducted 
within this total.  
 
Intervention 
Patients were randomly assigned to one of three conditions, two of which entailed an email. 
Each intervention is named and described in the pre-registration under “Groups and 
Interventions.”  
 
Outcomes Timeframe 
As described in the “Outcome Measures” section of the pre-registration, we examined study 
outcomes within one week (or 7 days) after they received the intervention (for the patients in 
the email groups) or, for the control group, within one week after they would have received the 
intervention had they been in an email group. For example, if the patient was emailed on 
5/20/20, we assessed if they had enrolled by 5/26/20. Secondary analyses examined study 
outcomes within one month (or 31 days) after the intervention. 
 
 
 

Statistical Analysis Plan 
 
The primary question of interest was whether a timely email improves one-week patient portal 
enrollment when compared with no such email. This was evaluated using a logistic regression (a 
generalized linear model with a binary distribution and log-link function) in an intent-to-treat 
design: patients who were randomized to receive an email but whose addresses were scrubbed 
by the email delivery software were still included in any such comparisons with the control 
group, so the total sample size was N = 5,099. 
 
A secondary question of interest was whether one email version performed better than the 
other. This question was assessed by examining whether a patient opened the email, clicked on 
the registration link in the email, unsubscribed from email communications, or enrolled within 
the outcome timeframe (1 week). This was evaluated for all four outcome measures using a 
logistic regression (a generalized linear model with a binary distribution and log-link function). 
These analyses focused on patients’ responses to the two email conditions and thus only 
included patients who were successfully sent the email, N = 2,075. Unsubscribe data was 
unexpectedly unavailable at 1-week post-intervention, so this measure was collected and 
analyzed at 1-month post-intervention instead. 
 
Finally, for the primary question of interest, a secondary analysis was conducted 1 month (31 
days) after the intervention. 
 
For all tests, odds ratios (ORs) were calculated, along with 95% confidence intervals (CIs); two-
tailed p-values < 0.05 were used to determine statistical significance.