The suffering measurement instruments in palliative care: A systematic review of psychometric properties

Background: The relief of suffering is considered one of the main goals to reach at the end of life, and nurses play an essential role in the prevention and relief of suffering. Validated instruments for assessing suffering can be useful, and selection of the most appropriate measure is crucial. To date, no systematic review has been performed that contrasts the measurement properties of instruments assessing suffering in the palliative care population, according to the most up-to-date COnsensus-based Standards for the selection of health status Measurement INstruments methodology. Objectives: The aim of this systematic review is twofold: (1) identify the measures assessing suffering in the palliative care population, and (2) assess the measurement properties of these measures. Design: A systematic review of the measurement properties of instruments assessing suffering in palliative care was carried out. Data sources: The search strategy was conducted in Medline, CINAHL, PsycINFO, Web of Science, Cochrane Library, SciELO, Scopus, Cosmin database of systematic reviews and Open gray. Review methods: The following methodologies were applied: updated COnsensus-based Standards for the selection of health status Measurement INstruments, the Meta-Analysis of Observational Studies in Epidemiology, and the Assessing the Methodological Quality of Systematic Reviews tool. A protocol for this systematic review was registered in PROSPERO (Registration number: CRD42018106488). Eligible studies were those that satisfied the following criteria: a) validation studies of measures assessing suffering in the palliative care population, b) assessing at least one measurement property of a measure, c) published in English or Spanish and d) published between January 1980 and September 2019. The included studies were assessed for the methodological quality of the measurement properties and then compared in terms of both the measurement properties and the methodological quality of the processes used. The evidence for each measurement property was summarised and the quality of the evidence was graded using the Grading of Recommendations, Assessment, Development and Evaluation approach. Results: The search strategy yielded a total of nine studies and six instruments assessing suffering. The methodological quality of the studies was doubtful and the quality of the evidence was moderate for most of the measurement properties analysed. The Suffering Pictogram was the instrument with the best rating for methodological quality and quality of evidence, for most of the measurement properties evaluated. Conclusions: Instruments assessing suffering in palliative care have been identified in this systematic review. The Suffering Pictogram seems to be the most useful instrument identified. Tweetable abstract: The relief of suffering is one of the main goals to reach at the end of life, and the selection of the most appropriate measure for assessing this construct is crucial. (C) 2020 Elsevier Ltd. All rights reserved.