Abstract
BACKGROUND: Prognostic nutritional index (PNI) has been extensively investigated for its effect on forecasting multiple myeloma (MM) survival; however, the conclusions are conflicting. This meta-analysis identified an accurate MM prognosis forecasting role for the PNI. METHODS: We systematically searched PubMed, Web of Science, Embase, Cochrane Library, and CNKI databases until July 2, 2025, and evaluated the overall survival (OS) and progression-free survival (PFS) forecasting ability of the PNI by determining pooled hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: This study included seven articles involving 1120 participants. From the pooled findings, a lower PNI exhibited a remarkable correlation with unfavorable OS (HR = 2.62, 95% CI = 1.76-3.89) and shorter PFS (HR = 1.52, 95% CI = 1.23-1.89, p<0.001) of MM. Additionally, lower PNI was significantly associated with ISS stage III (odds ratio [OR]=1.80, 95% CI = 1.19-2.73, p=0.005). However, PNI did not have a marked correlation with sex (OR = 1.02, 95% CI = 0.71-1.47, p=0.900), age (OR = 1.1, 95% CI = 0.70-1.93, p=0.558), and lactate dehydrogenase (OR = 0.98, 95% CI = 0.57-1.69, p=0.955) in MM. The meta-analysis had some limitations, such as retrospective design, small sample size, and inconsistent cut-off values of PNI. CONCLUSION: Collectively, the present work including 1120 patients showed the relationship between a lower PNI and unfavorable MM OS and PFS. Furthermore, a lower PNI was significantly associated with an advanced ISS stage of MM. The PNI can be a creditable and cost-effective factor for forecasting MM prognosis.