Risk of bias analysis.

Objective
It still needs to be determined if platelet-rich plasma (PRP) has any added advantage over Minoxidil in treating androgenetic alopecia. We reviewed randomized controlled trials (RCTs) comparing scalp injections of PRP plus Minoxidil vs Minoxidil alone for managing androgenetic alopecia.
Methods
All RCTs published on Embase, Cochrane Library, and PubMed comparing PRP plus Minoxidil vs. Minoxidil alone were eligible. The literature search was completed on 5 March 2024. The review was registered on PROSPERO (CRD42024509826).
Results
Of five included RCTs, three had a high risk of bias, while one had some concerns. A systematic review of the studies showed that all trials reported better outcomes with PRP plus Minoxidil than with Minoxidil alone. Meta-analysis showed that hair density at one month (MD: 11.07 95% CI: 1.20, 20.94 I2 = 0%), three months (MD: 21.81 95% CI: 10.64, 33.00 I2 = 57%) and 5/6 months (MD: 17.80 95% CI: 7.91, 27.69 I2 = 80%) of follow-up was significantly better in the PRP plus Minoxidil vs the Minoxidil alone group. Meta-analysis of adverse events showed that the risk of adverse events was comparable in both groups (OR: 0.55 95% CI: 0.22, 1.36 I2 = 0%). The certainty of evidence on the GRADE assessment was "low to very low."
Conclusion
Very low-quality evidence shows that the addition of injectable PRP to topical Minoxidil may improve outcomes in patients with androgenetic alopecia. The addition of PRP was found to improve hair density and patient satisfaction significantly. However, the small number of studies with a high risk of bias and heterogeneity in PRP preparation methods are significant limitations of current evidence. Further studies with larger sample sizes and uniform PRP preparation protocols are needed.

研究目标：目前尚不清楚富血小板血浆（platelet-rich plasma, PRP）相较于米诺地尔（Minoxidil）治疗雄激素性脱发（androgenetic alopecia）是否具备额外获益。本研究对比较头皮注射富血小板血浆联合米诺地尔与单用米诺地尔治疗雄激素性脱发的随机对照试验（randomized controlled trials, RCTs）开展了系统回顾。

研究方法：纳入所有在Embase、Cochrane图书馆及PubMed上发表的、比较富血小板血浆联合米诺地尔与单用米诺地尔的随机对照试验。文献检索完成于2024年3月5日，本系统回顾已在PROSPERO平台注册（注册号：CRD42024509826）。

研究结果：纳入的5项随机对照试验中，3项存在较高偏倚风险，1项存在一定偏倚风险疑虑。对纳入研究的系统回顾显示，所有试验均报告富血小板血浆联合米诺地尔组的治疗效果优于单用米诺地尔组。Meta分析结果表明，在随访1个月（均差(MD): 11.07，95%置信区间(CI): 1.20~20.94，I²=0%）、3个月（均差(MD): 21.81，95%置信区间(CI): 10.64~33.00，I²=57%）及5/6个月（均差(MD): 17.80，95%置信区间(CI): 7.91~27.69，I²=80%）时，富血小板血浆联合米诺地尔组的毛发密度均显著优于单用米诺地尔组。针对不良事件的Meta分析显示，两组不良事件发生风险相当（比值比(OR): 0.55，95%置信区间(CI): 0.22~1.36，I²=0%）。采用GRADE分级对证据质量进行评估，结果为"低至极低质量"。

研究结论：极低质量证据表明，在外用米诺地尔基础上加用注射用富血小板血浆，或可改善雄激素性脱发患者的治疗结局。研究发现，加用富血小板血浆可显著提升毛发密度与患者满意度。但当前证据存在显著局限性：纳入研究数量较少且偏倚风险较高，同时富血小板血浆的制备方法存在异质性。未来仍需开展样本量更大、富血小板血浆制备方案统一的相关研究。