Forest plot of the effect of NHT plus RP versus RP alone on PSM rates. Subgroup analysis of PSM by country of origin. The effect of NHT + RP versus RP alone stratified by geographic location. Subgroup analysis of PSM by treatment duration. Comparison of short-term (<6 months) and long-term (≥6 months) NHT before RP. Subgroup analysis of PSM by sample size. Studies with sample size <150 versus ≥150. Subgroup analysis of PSM by study quality based on risk of bias assessments.