Prognostic Impact of Bone Marrow Plasma Cell Percentage in Patients With Systemic Light‐Chain Amyloidosis: A Systematic Review and Meta‐Analysis

The prognostic value of bone marrow plasma cell percentage (BMPC%) in systemic light-chain (AL) amyloidosis remains controversial. This meta-analysis aimed to determine the association between BMPC% ≥ 10% and survival outcomes in patients with AL amyloidosis. We systematically searched multiple databases for studies published through September 2025. Ten studies involving 5322 patients were included. A BMPC% ≥ 10% was significantly associated with poorer OS (pooled HR = 1.35, 95% CI [1.13, 1.62], p = 0.001) and PFS (pooled HR = 1.63, 95% CI [1.29, 2.04], p < 0.001). Consistently, patients with BMPC% ≥10% had significantly shorter mean OS (MD = -31.79 months, 95% CI [-43.22, -20.36], p < 0.0001) and mean PFS (MD = -16.12 months, 95% CI [-40.69, -1.54], p < 0.0001). Significant heterogeneity was observed, for which study design was identified as a major source. Evidence of publication bias was present. This meta-analysis provides robust evidence that a BMPC% ≥ 10% is an independent predictor of inferior OS and PFS in AL amyloidosis. Integrating this readily available biomarker with existing cardiac-based staging systems could enhance risk stratification and inform clinical decision-making.