Advance directives in amyotrophic lateral sclerosis - a systematic review and meta-analysis.

Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of the upper and lower motoneuron. It is associated with a life expectancy of 2-4 years after diagnosis. Individuals experience paralysis, dysphagia, respiratory failure and loss of communicative function, rendering advance care planning (ACP) critically important. This systematic review primarily aimed to internationally compare the application of advance directives (AD) and ACP in ALS. Its secondary aim was to identify ACP preferences, identify fields for future research and to generate recommendations for improving patient care through ACP.

Methods: We conducted a systematic literature review and meta-analysis. Five electronic databases (Embase, Medline, Scopus, PsycInfo and CENTRAL) were searched for qualitative and quantitative primary literature from 1999 to 2024. Cross-references were used to identify additional publications. Study selection was performed based on inclusion criteria. Number and content of AD were extracted systematically. After statistical analysis consecutive meta-analysis was performed for international differences and changes over time. Quality assessment of studies was performed using the MMAT (Mixed Methods Appraisal Tool). PROSPERO Registration (June 07, 2021) : CRD42021248040.

Results: A total of 998 records was screened of which 26 were included in the synthesis. An increase in publication numbers of 88.9% was observed from 1999 to 2024. Results regarding use and content of AD were heterogeneous and international differences were detected. AD were signed in 60.4% of records (1,629 / 2,696 patients). The number of AD decreased over time when separating the review period in two decades (1st 1999-2011: 78% vs. 2nd 2012-2024: 42%). Study quality was superior in qualitative and mixed method designs compared to quantitative studies.

Conclusion: Further prospective studies should include detailed analyses on preferences regarding ventilation and artificial nutrition in ALS and should encompass countries of the global south. Despite the complexity of ACP with regard to individual patient needs, ACP should be part of each individual support plan for ALS patients and should specifically comprise a discussion on the preferred place of death. The available disease-specific AD documents should be preferred.