NPPB and acute kidney injury: This diagnosis was based on the presence of three prognostic risk variables (troponin ≥0.1, BNP ≥400, NT-ProBNP ≥1,800, and dFLC ≥180 mg/L), and evidence of multi-organ involvement: cardiac (elevated NT-proBNP in the absence of renal failure), gastrointestinal (amyloid deposit in stomach), renal (proteinuria), and nervous system (peripheral neuropathy, voiding problems, and gastric emptying disorder).