# Diabetes Mellitus is a Risk Factor for Developing CMV Retinitis in Solid Organ Transplant Recipients: A Case-control Study

## TL;DR

This study found that diabetes increases the risk of CMV retinitis in organ transplant patients, a rare but late complication.

## Contribution

The study identifies diabetes mellitus as an independent risk factor for CMV retinitis in solid organ transplant recipients.

## Key findings

- The incidence of CMV retinitis was 5.3 per 10,000 person-years in solid organ transplant recipients.
- Diabetes mellitus was independently associated with a 16.5-fold increased odds of developing CMV retinitis.
- CMV retinitis typically occurs 3.4 years post-transplant and is more common in kidney transplant recipients.

## Abstract

The incidence of cytomegalovirus retinitis (CMVR) in solid organ transplant (SOT) recipients may be increasing due to improved long-term survival post-transplant. However, the epidemiology of CMVR after SOT is not well described. We therefore aimed to determine the incidence of CMVR and identify risk factors for its development post-SOT.

Case-control study at a 1:4 ratio between January 1, 2012 and March 31, 2024. Cases were SOT recipients at 1 of 2 British Columbia transplant centres diagnosed with CMVR clinically or through ocular fluid viral PCR. Controls were matched on transplant organ, year, and center. Univariable and multivariable analyses were performed using conditional logistic regression models.

Out of 5877 SOT recipients followed during the study period, there were 16 CMVR cases with an incidence rate of 5.3 per 10 000 person-years. Fourteen eligible cases of CMVR were matched to 56 controls. Cases were older than controls (median age 60.9 vs 42.6 years) and more likely to have diabetes mellitus (DM) (9 [64.3%] vs 9 [16.4%]), chronic heart disease (4 [28.6%] vs 4 [7.3%]), and CMV DNAemia any time post-SOT (12 [85.7%] vs 19 [35.2%]). Most received kidney transplants (50.0%), and the median time to CMVR was 3.4 years. After adjusting for age at transplant, DM, chronic heart disease, CMV DNAemia, and significant lymphopenia, only DM was associated with an increased odds of CMVR (odds ratio 16.5 [95% confidence interval, 1.12–243.8]).

CMVR is a rare and late complication post-SOT. DM was independently associated with increased odds of CMVR post-SOT.

In this case-control study in SOT recipients, the incidence of CMV retinitis was found to be 5.3 per 10 000 person-years, with a cumulative incidence of 0.3%. DM was independently associated with increased odds of CMV retinitis post-transplant.