Diabetes mellitus is a highly prevalent metabolic disorder associated with chronic, low-grade inflammation. Of recent interest is the association between diabetes and circadian rhythm disruption. The aim of this review is to evaluate and synthesise clinical evidence for whether diabetes affects homeostatic diurnal patterns to proinflammatory markers in the human body. This could inform the optimal timing of immune-targeted therapies over the course of the day.

This systematic review will include primary clinical research studies reporting on diurnal variations, defined as an afternoon/evening (PM) minus a morning (AM) value, within a timeframe of 12±4 hours, for predefined proinflammatory markers, in individuals with diabetes (type 1 or type 2) compared with healthy controls. A search of online databases (Cochrane CENTRAL, Ovid MEDLINE and Ovid Embase) will be performed. Grey literature searches will be performed in clinical trial registries. Two review authors will independently screen retrieved citation records at the title/abstract and full-text levels. Study quality will be assessed using an appropriate National Institute of Health quality assessment tool. A meta-analysis will be performed if more than one study reports equivalent data for any outcome. Statistical heterogeneity will be assessed using the ² test. Where a meta-analysis is not possible or unlikely to be meaningful, a narrative synthesis of the findings will be provided.

Ethics approval is not required for this systematic review as no original data will be collected. The results will be disseminated through peer-reviewed publication and conference presentations.

CRD420251115780.

Diabetic retinopathy (DR) in pregnancy can cause blindness. National guidelines recommend at least one eye examination in early pregnancy, then ideally 3-monthly, through to the postpartum for pregnant women with pregestational diabetes. Here we examined adherence rates, barriers and enablers to recommended DR screening guidelines.

Cross-sectional survey study, as part of a larger prospective cohort study.

Participants were recruited from two tertiary maternity hospitals in Melbourne, Australia.

Of the 173 pregnant women with type 1 (T1D) or type 2 diabetes (T2D) in the main cohort study, with an additional four who participated solely in this survey study, 130 (74.3%) completed the survey.

This study calculated rates of adherence to guideline-recommended DR screening schedules and collected data on the enablers and barriers to attendance using a modified Compliance with Annual Diabetic Eye Exams Survey. Each of the 5-point Likert-scale survey items was compared between adherent and non-adherent participants using the Wilcoxon rank-sum test and logistic regression models were constructed to quantify associations as ORs.

A retinal assessment was undertaken at least once during pregnancy in 86.3% of participants, but only 40.9% attended during their first trimester and only 21.2% attended the recommended number of examinations. Competing priorities were the main barriers to adherence, with eye examinations ranked as the fourth priority (IQR 4th–5th) among other health appointments during pregnancy. Meanwhile, knowledge of the benefits of eye screening examinations, eye-check reminders and support from relatives was identified as enablers.

Despite the risk of worsening DR during pregnancy, less than half of the participants adhered to recommended screening guidelines, suggesting that eye health is not a priority. Proactive measures to integrate care are needed to prevent visual loss in this growing population.