Fig. 5: Forest plot of included studies evaluating postprandial ghrelin.

Postprandial plasma levels of active and total ghrelin in patients with PD and in the control group were compared using standardized mean differences (SMD) and 95% confidence intervals. Significant reductions were observed in both total (SMD: −0.45, 95% CI −0.62, −0.29; Z = 5.42; P < 0.00001) and active (SMD: −0.80, 95% CI −1.24, −0.35; Z = 3.51; P = 0.0004) ghrelin. Moderate heterogeneity was found for total ghrelin (Tau² = 0.04; Chi² = 29.61, df = 21, P = 0.10; I² = 29%), while high heterogeneity was observed for active ghrelin (Tau² = 0.46; Chi² = 56.74, df = 10, P < 0.00001; I² = 82%). There were no significant subgroup differences (Chi² = 2.02, df = 1, P = 0.16; I² = 50.4%).