Table 1 Baseline characteristics of included studies
Author | Year | Country | No. of patients | Design | Risk of bias |
|---|---|---|---|---|---|
Deng [21] | 2013 | China | Â | Retrospective | Moderate risk |
 HHR |  |  | 20 |  |  |
 LHR |  |  | 20 |  |  |
Taqi [20] | 2013 | China | Â | Retrospective | Moderate risk |
 HHR |  |  | 5 |  |  |
 LHR |  |  | 20 |  |  |
Zhu [22] | 2014 | China | Â | Retrospective | Moderate risk |
 HHR |  |  | 102 |  |  |
 LHR |  |  | 152 |  |  |
Ozturk [23] | 2015 | Turkey | Â | Retrospective | Moderate risk |
 HHR |  |  | 16 |  |  |
 LHR |  |  | 12 |  |  |
Ye [24] | 2015 | China | Â | Retrospective | Moderate risk |
 HHR |  |  | 16 |  |  |
 LHR |  |  | 20 |  |  |
Wang [26] | 2017 | China | Â | Retrospective | Moderate risk |
 HHR |  |  | 25 |  |  |
 LHR |  |  | 20 |  |  |
Chen [27] | 2017 | China | Â | Retrospective | Moderate risk |
 HHR |  |  | 33 |  |  |
 LHR |  |  | 37 |  |  |
Ahonen [15] | 2017 | Finland | Â | Retrospective | Moderate risk |
 HHR |  |  | 24 |  |  |
 LHR |  |  | 38 |  |  |
Halka [25] | 2018 | United States | Â | Retrospective | Low risk |
 HHR |  |  | 25 |  |  |
 LHR |  |  | 57 |  |  |
Liu [29] | 2019 | China | Â | Retrospective | Moderate risk |
 HHR |  |  | 12 |  |  |
 LHR |  |  | 23 |  |  |
Zhao [30] | 2019 | China | Â | Retrospective | Moderate risk |
 HHR |  |  | 14 |  |  |
 LHR |  |  | 16 |  |  |
2018, 2020 | Finland | Â | RCT | Low risk | |
 HHR |  |  | 90 |  |  |
 LHR |  |  | 94 |  |  |
Tian [32] | 2020 | China | Â | Retrospective | Moderate risk |
 HHR |  |  | 20 |  |  |
 LHR |  |  | 21 |  |  |
Yang [33] | 2022 | China | Â | Retrospective | Moderate risk |
 HHR |  |  | 153 |  |  |
 LHR |  |  | 73 |  |  |