Effectiveness of Multidisciplinary Protocolised Interventions on IVT Non-adherence Rates

• multidisciplinary protocolized intervention (MPI) (Behavioral): Our novel proposed approach to improve adherence to IVT is personalized patient-centred care comprising a multidisciplinary protocolized intervention (MPI), which consists of medical consultation, to optimize the treatment regimen, and combinations of appropriate referrals to either (1) a nurse-directed patient education program (NE), (2) a low vision optometrist (OP), (3) an occupational therapy services (OT) and/or (4) a medical social worker (SW).
• Routine medical care & monitoring (Behavioral): The CAT scores will be recorded by the clinical research coordinator at baseline and follow-up visits for comparison to the MPI arm.

Primary outcomes

• Effectiveness of multidisciplinary protocolized intervention (MPI) in improving adherence to intravitreal (IVT) Injection. [From 6 month to 18 months.]: Adherence is defined as 1. patient attends all follow-up appointments within 1 month of the planned follow up date, and 2. patient receives IVT within 1 month of when the doctor recommends IVT. At each follow up time point, the study team will assess if the patient has been "adherent" or "non-adherent". If the patient does not visit the clinic or does not attend the scheduled study visit, phone calls will be made to determine reasons or barriers for adherence. A remote invitation to complete the CAT questionnaire will also be sent to these patients or if uncontactable, they will be approached and interviewed at their next clinical visit. For previously treated patients, adherence status up to 2 years prior to study enrolment for the time of IVT treatment will be recorded by the study team from medical records.

Secondary outcomes

• Comparison of CAT scores (Specific aim 2A) from the CAT questionnaire database [Baseline, 6,12 and 18 month]: CAT scores will be collected via a hybrid remote or in-clinic delivery method. At baseline, CATs will be administered in-clinic or via CAT links sent by WhatsApp to their contact number . At subsequent timepoints, relevant CAT links will be sent via a WhatsApp message to their designated contact number, to complete the questionnaire remotely on their own SMART device, before their appointment. Those who are unable to complete CAT testing remotely will be given an additional opportunity to complete them in-clinic using an internet enabled tablet in person at their clinic visit with/without CRC assistance. The CAT scores will be assessed by clinical research coordinator.
• Effectiveness of MPI in improvement of visual function [Enrolment to 18 months]: Visual function -Monocular and binocular presenting corrected VA and CS (Specific aim 2B) will be collected from the clinical records. If data are not present, the CRCs will conduct these tests on participants using standardized protocols.domain-specific CAT scores at each follow-up time point. Compared to those in standard care, patients in the MPI group will have improved VA and CS at each follow-up time point.
• Effectiveness of MPI in increasing disease-free intervals in patients with nAMD or DME receiving IVT and having suboptimal CAT scores. [At the end of 18-month time point.]: Disease free intervals as defined by the maximum IVT treatment interval where no disease activity recurrence is detected on OCT will be collected from clinical records and OCT images from the clinical database (Specific aim 2B).
• The implementation outcomes of MPI through mixed method testing with interviews and questionnaires (Specific aim 3). [6 to 15 months.]: The PI, assisted by their Co-Is and collaborators, will identify eligible individuals for qualitative interviewing that will be performed with major stakeholders between 6 to 15 months timeline. These include the clinicians, nurses and the allied health specialists (OP, OT and SW) who will be involved in administering the MPI, and patients and care-givers who receive the MPI. Potential individuals will be contacted over email or phone call, and a trained study team will follow up on affirmative responses by obtaining written informed consent to carry out the following study procedures. Semi-structured (1-on-1) interviews with the above key stakeholders will be conducted to explore their perspectives on barriers and enablers of integrating MPI into a Singapore public hospital for the management of nAMD and DME patients receiving IVT. Purposive and snowball sampling will be used to ensure all stakeholder groups are represented. Interviews will be conducted until no new data emerges.
• To assess the cost-effectiveness of the MPI for improving adherence to IVT, considering its potential impact on long term visual acuity (VA) loss and QoL adjusted years (QALYs). [Baseline and 18-month]: The sample size required for cost-effectiveness analysis is usually larger than clinical studies as it involves estimating the joint distribution of patient outcomes and costs. Furthermore, power calculations require setting a willingness-to-pay threshold, which is not known for Singapore. However, as cost-effectiveness is more concerned with estimating effect size rather than hypothesis testing, it can still provide valuable information even if underpowered. Instead of confidence intervals, sensitivity analysis will be used to assess the range of estimated values.

Sex: All

Inclusion Criteria:

* Patients with chronic macula disease including those diagnosed with nAMD and DME, who require IVT.
* This would include treatment naive patients (no IVT in either eye the last 6 months) and previously treated patients who have had IVT in either eye in the last 6 months and require further IVT treatment at the baseline study visit in either eye.
* Able to provide informed consent and must consent to undergoing the MPI intervention.
* Speak English or Mandarin.
* Must be a Singapore resident.

Exclusion Criteria:

* Patients who are unwilling or unable to perform CAT testing.
* Unable to provide informed consent.
* Significant eye pathology such as cornea problems, glaucoma, or other retinal diseases that may substantially affect vision.
* Do not speak English or Mandarin fluently.
* Cognitive impairment (as assessed using 6CIT).
* Obvious observable physical or hearing disabilities that prevents them from completing the CAT questionnaire and undergoing MPI effectively.

• Study Protocol (PDF, 2026-01-24)

• Anna CS Tan, PhD, Principal investigator, Singapore Eye Research Institute (SERI)