Fig. 4: Forest plot of time-to-SCD predictors showing median conversion times (years) and hazard ratios in the cross-cohort analysis.

The plot illustrates how multiple clinical predictors affect subjective cognitive decline (SCD). The left panel shows median time to SCD onset with 95% confidence intervals (CIs), comparing subgroups for each predictor. Solid blue lines indicate statistically significant differences between groups (p-value < 0.05), while grey lines indicate non-significant differences. Key predictors include MDS-UPDRS Part I score (≥12 vs <12), postural abnormalities, tremor characteristics, and age at PD diagnosis (≥62 vs <62 years). The right panel displays corresponding hazard ratios (HR) with 95% CIs, where values > 1 indicate increased risk. Notable findings include a significantly higher SCD risk for patients diagnosed after age 62 and those with higher MDS-UPDRS Part I scores. Some features such as sleep problems and REM sleep behavior disorder show wider confidence intervals, suggesting more uncertainty in their predictive value.