Trial design
A single-masked randomized controlled trial (RCT) with balanced randomization. The trial was registered at clinicaltrials.gov (NCT03927859) on April 25, 2019.
Participants
Eligibility
Patients over 18 years of age with a diagnosis of Type 1 or 2 Diabetes Mellitus. Patients with diabetes were defined as patients whose chart contained an Ontario Health Insurance Plan (OHIP) code K030 (Diabetes Management Assessment) more than once or a problem list containing either “DM”, “dm” or “diabetes”. Patients who had a record in their chart of having been screened within the last 12 months were excluded from the study.
Settings
In Ontario, Canada, while the teleophthalmology program has been in practice for almost 20 years in rural regions, the urban program has been in practice since 2013 and was developed in response to the finding that many underscreened individuals live in urban areas(5). The program was initially set up through Community Health Centers (CHCs), but started expanding to other primary care settings outside CHCs. With the goal to expand the program to more settings outside CHCs, the program was introduced to an urban academic team-based primary care practice. The urban program in Toronto, Ontario is currently deployed at 11 core sites across the province (https://otn.ca/providers/ophthalmology/). Staff from each core site carry equipment to various satellite locations. Together with the core sites, the program provides services to 74 sites across Ontario. The focus of the program is to provide screening services for underserved and vulnerable groups and/or regions. Patients can be referred to the program either by a primary care physician, a nurse practitioner or a diabetes education program personnel. The cost of delivery is covered by the publicly funded healthcare system in Ontario (OHIP). The study was conducted at one of the satellite locations of the Toronto, Ontario teleophthalmology program: Women’s College Hospital Family Health Team, a hospital affiliated primary care team-based practice. Family Health Teams in Ontario, Canada consist of a team of family physicians and nurse practitioners, supported by registered nurses, social workers, dietitians, and other professionals. The practice had recently (within a month) become a satellite site for teleophthalmology, meaning that a nurse was available once a week to screen patients locally.
Interventions
Patients were randomized to one of four intervention groups: a phone call, a letter, a letter plus phone, and usual care. Patients assigned to the phone call intervention were contacted by an administrative staff who informed them that they were calling from the family practice and asked them whether they have had their diabetes eye screening exam completed in the recent year. Patients who indicated that they were not screened and who did not have a pre-existing scheduled appointment, were offered to make a booking for the teleophthalmology program and to be screened at the family practice. Patients who were assigned to the letter intervention received a letter in the mail from the practice stating that they were due for DR screening and provided them with a list of options for screening: receive a referral for ophthalmology from their family doctor, go to an optometrist’s office or visit the teleophthalmology program at their clinic. The letter also included a brochure about the teleophthalmology program. Patients in the letter plus phone group were sent out the letter and then were contacted by phone a week later. The usual care group was called a month after the trial was initiated to ask patients whether they have been screened and obtain a baseline screening rate for the usual care group. Usual care at this practice consisted of primary care providers asking patients during a routine visit whether they have been screened for DR within the last year and providing a referral to an optometrist, an ophthalmologist or the local teleophthalmology program for the screening. When referral was made, patients received a call with the date of their appointment from the primary care practice.
Randomization:
The four physicians with largest numbers of patients with diabetes mellitus at the practice and one physician with just a few patients participated in the study. The rest of the physicians in this practice were allocated to a concurrent physician engagement study that required a larger number of physicians and were as a result excluded from the trial. The five participating physicians initially had a total of 215 eligible patients with diabetes, but upon closer review of the list, only 182 patients met the inclusion criteria to be randomized. Once a comprehensive list of patients with diabetes across the rosters of these five physicians was collected, they were allocated to groups by matching the list of names to a randomly created sequence of group allocations that were created on the randomizer.org site. The list contained a random sequence of one of the 4 groups in a 1:1:1:1 ratio.
Outcomes
The primary outcome was the total number of patients who made a booking with teleophthalmology. This was assessed at the time of the call for interventions that involved a call and for the Mail group these data were collected by making a phone call a month after the letters were sent out.
Sample size
A recent systematic review of quality improvement interventions targeting diabetic retinopathy screening concluded that the interventions result in a risk difference of 17% on average(7). Using this information, we assumed that if 50% of the patients at baseline were to be screened, then 67% of patients in the intervention groups would be screened or booked for screening post-intervention. The resulting required sample size with an alpha= .05, one-tailed, and to achieve a power of 0.80, was 210.
Masking
This was a single-masked trial. Patients were not aware that they were part of a study until the end of the call or the time that they were contacted (for letter only and control group).
Statistical methods
We ran a linear model logistic regression with group assignment as the predictor variables and whether a patient made a booking with the teleophthalmology program as the outcome variable.