Fig. 3: Evolution of free light-chain (FLC) ratio in individuals with light-chain monoclonal gammopathy of undetermined significance.

The figure depicts the log₂-transformed fold-change in FLC ratio over time for repeated samples relative to the initial screening. This log transformation allows for proportional representation of changes centered at zero. Stratification is based on the FLC ratio cutoff of 3.15 at screening, with red dot representing 531 repeated samples from 124 individuals with an FLC ratio >1.65 to 3.15, and blue dots 511 repeated samples from 71 individuals with an FLC ratio >3.15. The corresponding lines indicate the effect on fold-change in FLC ratio, fitted separately for each group using a linear mixed-effects model, accounting for individual-level variation, and adjusted for age, sex, and eGFR. For the >1.65 to 3.15 (red line) group, the time effect estimate (years) was 0.011 (p = 0.056), and for the >3.15 (blue line) the estimate was 0.069 (p < 0.001). The median time from screening to the last sample was 54 months and 62 months, with a median of 4 and 6 repeated samples per individual, respectively.