Objectives In AL amyloidosis, organ response assessment is based on surrogates (eg, cardiac biomarkers). An objective functional test, such as the 6 min walk test (6MWT), capturing overall clinical improvement, is required. We aimed to evaluate the prognostic impact of the 6MWT at baseline and change following chemotherapy.
Methods This study evaluated the outcomes of patients who enrolled in a prospective observational study at the UK National Amyloidosis Centre (2012–2017). Patients underwent comprehensive assessments inclusive of blood testing, echocardiogram and 6MWT at baseline and annually thereafter.
Results In total, 799 patients were included within the study. Median baseline 6 min walk distance (6MWD) was 362 m (IQR: 231 m). 6MWD progressively decreased with worsening cardiac disease stage (458 m, 404 m, 331 m and 168 m for cardiac Mayo stages I, II, IIIa and IIIb, respectively (p<0.0001)). In patients with a baseline 6MWT of ≥350 m, the median overall survival was not reached (vs 30.0 (95% CI 23.2 to 36.8) months if <350 m and 5.0 (95% CI 2.8 to 7.2) months if unable to attempt 6MWT (p<0.0001). Following chemotherapy, only patients in a complete haematological response improved their 6MWD by 12 months (p=0.001). Improvement in 6MWD prolonged survival in patients with cardiac amyloidosis (p=0.005).
Conclusion The 6MWT is prognostic in AL amyloidosis. A baseline distance of ≥350 m independently predicts better survival. These data suggest that 6MWT has utility in AL amyloidosis for baseline prognosis and assessing response.
- Heart Failure
- Outcome Assessment, Health Care
Data availability statement
Due to ethical and confidentiality considerations, data cannot be shared but interested parties may directly contact the authors for any queries.
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Contributors OCC and ADW conceived the study, analysed data and wrote the manuscript. OCC, AS and RM collected the data. SR, DF, SL, SS, SM, CJW, HJL, PNH, JDG, AM-N and MF contributed to the manuscript and provided critical input. All authors reviewed the final version of the manuscript. OC and AW accept full responsibility for the work, conduction of the study. All authors had full access to data and agreed on decision to publish.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.
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