Systematic Review of Palliative Care research performed and published: Exploring the meta-research landscape and areas of improvement

Abstract

Background:

Palliative care aims to alleviate suffering, improve quality of life, and address distressing symptoms in people with advanced disease. Despite its clinical importance, many interventions—particularly pharmacological approaches—are supported by limited high-quality evidence, with recommendations often relying on expert consensus or long-standing routine. Clinical trials are essential to strengthen the evidence base, yet research in palliative care faces well-described barriers such as recruitment challenges, underpowered studies, and premature termination. To our knowledge, no meta-research study has systematically mapped the clinical-trial landscape in palliative care. This review intends to establish a benchmark for research activity, identify under-represented areas, and outline priorities for future investigation, including recruitment expectations and attrition estimates.

Objectives:

This systematic review provides a comprehensive overview of clinical trials conducted in palliative care over the past two decades. We aim to (1) quantify the number, scope, and characteristics of registered and published trials; (2) identify which symptoms and interventions are studied more intensively, and compare this with the known prevalence of symptoms in advanced disease; and (3) document rates and reasons for non-completion or non-publication of registered studies.

Methods:

We will search major trial registries (ClinicalTrials.gov, WHO ICTRP, EudraCT) and bibliographic databases for interventional studies in adult palliative-care populations registered between 2000 and 2020. Eligible studies include prospective interventional designs; pediatric studies and disease-modifying cancer therapies will be excluded. Two reviewers will independently screen records and extract data using piloted forms. Discrepancies between registered and published outcomes will be assessed, and reasons for non-publication will be sought by contacting investigators. Descriptive statistics will summarize study characteristics, with subgroup analyses by symptom category, intervention type, sponsor, and region. Meta-analysis of publication rates will be conducted if appropriate.