To describe prescription patterns, dosing and persistence of guideline-directed medical therapy (GDMT) among patients with heart failure with reduced ejection fraction in Singapore, and to identify factors associated with the use of quadruple therapy (ACE inhibitor (ACEi)/angiotensin II receptor blocker (ARB)/angiotensin receptor-neprilysin inhibitor (ARNI), β-blocker, mineralocorticoid receptor antagonist (MRA) and sodium-glucose cotransporter-2 (SGLT2) inhibitor).

Retrospective, observational cohort study.

Secondary and tertiary care settings across seven public hospitals in Singapore.

3999 adults hospitalised from 2020 to 2022 with a first heart failure-related admission and left ventricular ejection fraction ≤40%. Patients with absolute contraindications to specific GDMT classes were excluded from eligibility calculations.

Primary outcomes were the proportions of eligible patients prescribed each GDMT class and quadruple therapy at discharge. Secondary outcomes were 6-month prescription patterns, dose attainment and predictors of quadruple therapy use.

Among eligible patients, 80%–99% met criteria for each GDMT drug class, yet only 29% received quadruple therapy at discharge in 2022. Prescription rates for ACEi/ARB/ARNI (67%), beta-blockers (89%), MRAs (40%), and SGLT2 inhibitors (46%) remained suboptimal despite high eligibility. At discharge, over 90% of patients on ACEi/ARB/ARNI and beta-blockers received ≤50% of target doses. By 6 months, prescription rates declined by 16% for ACEi/ARB/ARNI, 26% for beta-blockers and 7% for MRAs, while SGLT2 inhibitor use increased. Older age (OR 0.97, 95% CI 0.96 to 0.98) and chronic kidney disease stage 3a–4 (OR 0.65 to 0.04) were associated with lower odds of receiving quadruple therapy, while significant institutional variation was observed.

Despite high eligibility, uptake and optimisation of GDMT remain poor in Singapore, with substantial treatment gaps driven by underprescription, inadequate dosing and discontinuation. Interventions targeting clinician awareness, postdischarge support and institutional practice variation may improve adherence to guideline-recommended therapy.

Patients with stage III non-small cell lung cancer (NSCLC) are at high risk of developing post-treatment recurrences (50–78%) during follow-up. As more effective treatments are now available, especially for patients with oligometastatic disease, earlier detection of recurrences may prolong survival and health-related quality of life (HRQOL). With the use of 2'-deoxy-2'-[¹⁸F]fluoroglucose positron emission tomography/CT ([¹⁸F]FDG PET/CT) during follow-up, recurrences may be detected earlier. Therefore, the primary objective of this study is to compare the 3-year overall survival of patients with stage III NSCLC during follow-up surveillance with [¹⁸F]FDG PET/CT versus follow-up with conventional CT (usual care). Secondary objectives address the number, location and timing of recurrences, as well as HRQOL, cost-effectiveness and patient experiences of PET/CT scans.

In this multicentre randomised controlled clinical trial, 690 patients with stage III NSCLC (8th edition International Association for the Study of Lung Cancer (IASLC) Tumor, Nodes, Metastasis (TNM) classification) who completed curative intended treatment and started follow-up care (which may include adjuvant therapy) will be randomised 1:1 to either the intervention ([¹⁸F]FDG PET/CT) or the control group (CT). Patients will undergo follow-up scans during visits at 6, 12, 18, 24 and 36 months. Data will be collected using validated questionnaires, electronic case report forms and data extractions from the electronic health records. Additionally, blood samples will be collected, and interviews will be conducted.

The study protocol has been approved by the Medical Ethical Committee of the Radboudumc and review boards of all participating centres. Written informed consent will be obtained from all participants. Study results will be published in international peer-reviewed scientific journals and presented at relevant scientific conferences. Data will be published in a data repository or other online data archive.

NCT06082492.