How Well Do Current Measures Assess the Impact of Advance Care Planning on Concordance Between Patient Preferences for End-of-Life Care and the Care Received: A Methodological Review.

BACKGROUND: Research has begun to focus on whether Advance Care Planning (ACP) has the capacity to influence care, and to examine whether ACP can be effective in meeting patients' wishes at the end of their lives. Little attention has been paid, however, to the validity and clinical relevance of existing measures.
METHODS: A search of Medline and CINHAL identified ACP studies measuring concordance between end-of-life (EoL) preferences and the care received. Databases were searched from 2000 to August 2016. We developed a checklist to evaluate the quality of included studies. Data were collected on the proportion of patients who received concordant care, extracted from manuscript tables or calculated from the text. OUTCOMES: Of 2941 papers initially identified, nine eligible studies were included. Proportions of patients who received concordant care varied from 14% to 98%. Studies were heterogeneous and methodologically poor, with limited attention paid to bias/external validity. Studies varied with regards to design of measures, the meaning of relevant terms like "preference" "EoL care" and "concordance," and the completeness of reported data.
CONCLUSION: Methodological variations and weaknesses compromise the validity of study results, and prevent meaningful comparisons between studies or synthesis of the results. Effectively evaluating whether ACP interventions enhance a patient's capacity to receive the care they want requires harmonization of research. This demands standardization of methods across studies, validating of instruments, and consensus based on a consistent conceptual framework regarding what constitutes a meaningful outcome measure.