Strengths and Limitations
DIABETES
The strengths of this study include the randomized factorial design and the pragmatic implementation, where interventions were fully managed by administrative staff at the primary care practice, both of which increase external validity. Our study also has several limitations. First, this was a study that was conducted within the context of a large, academic, team-based primary care practice with external funding to pay for additional time for a casual staff member. This would be more difficult to execute without additional administrative support in smaller settings. Second, our interventions (ie, letter or phone call) limit our sample to patients who have a phone and an address, speak English, and have the literacy required for being able to read. As such, generalizability of our findings is limited to these patient populations. Third, we had to exclude a subset of providers from the study due to another concurrent physician trial being conducted; many patients had been screened already at the time they were contacted, and some asked their data to be excluded from analyses; as a result, our final sample size was much smaller than initially planned; nonetheless, the results with regard to the effectiveness of phone calls are quite evident. Our results suggested that phone calls are likely to be superior to letters, but we were unable to examine the effect of the interaction between phone call and letters, as all the patients assigned to the phone call and letter group booked an appointment. A larger sample size is needed to confirm the effects of that interaction. Finally, our primary outcome was booking of an appointment, and we were unable to link attendance to the screening appointment or attendance of screenings outside the teleophthalmology program. Many patients were booked for screening several months after the time of booking, and the project was set to be completed before the time of bookings; therefore, we were not able to ascertain exactly which patients eventually attended the booking. We do know from communication with the program, however, that 78% of the patients who booked a teleophthalmology appointment with the physicians whose patients participated in this trial have shown up for their teleophthalmology appointment.This study demonstrated that phone calls were highly effective in recruiting patients to an urban teleophthalmology program, but this intervention may be difficult to scale without external funding due to capacity constraints in primary care. Future studies could focus on regional support for different methods of directly reaching out to patients, such as letters with a stronger educational component, personalized letters, emails, and text messages. Having the ability to link health administrative data that verify whether the patient has been screened and providing primary care practices with a list of patients who have not been screened is also another approach that would enable practices to more accurately target patients who have not been screened.The authors would like to thank the Women’s College Hospital Family Health Team staff for supporting the study and assisting in its implementation. The authors would also like to thank the Toronto Teleophthalmology Program’s staff for their support. Finally, the authors would like to thank all patients who volunteered to share their information for the study. Funding for this study was provided by Diabetes Action Canada.Authors' Contributions: VS had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. VS also drafted the manuscript and performed the statistical analysis. VS, MN, NO, RM, OS, KM, IW, LIB, RSB, MHB, and OB contributed to the design of the study; the acquisition, analysis, and interpretation of data; and the critical revision of the manuscript for important intellectual content. OB supervised the study and is the guarantor. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.Conflicts of Interest: None declared.