期刊更正指標性瑞典研究：重新分析發現性別手術對心理健康沒有益處

一項關鍵研究的更正：沒有證據表明「性別確認」手術可以改善心理健康

Authors: Society for Evidence-Based Gender Medicine (SEGM)
Journal: Society for Evidence-Based Gender Medicine (SEGM)
Year: 2020
Source: segm.org/ajp_correction_2020

Summary

A 2019 Swedish study by Bränström and Pachankis in the American Journal of Psychiatry was widely reported as showing that gender surgery improves mental health. People whose surgery was longer ago were less likely to be getting mental health care in 2015; hormones showed no such link. After critical letters, the journal asked statisticians to review it and asked the authors to compare 1,018 surgery patients with 1,018 similar people who had not had surgery. That comparison showed 'no advantage of surgery'. The 2020 correction called the pro-surgery conclusion 'too strong' and fixed a 48% vs 37.9% error. This SEGM (Society for Evidence-Based Gender Medicine) article explains the correction accurately. But the new comparison was an afterthought, not part of the original plan, the paper was not withdrawn, and SEGM is a side in the debate.

Key findings

2019 年的原始研究使用涵蓋 970 萬人的瑞典全國健康紀錄，其中包括 2005 至 2015 年間被診斷為性別不一致的 2,679 人，並只看單一年份 2015 年的心理健康治療。
研究發現使用荷爾蒙的年數與心理健康治療之間沒有關聯，但自最後一次手術後每多一年，接受治療的機率約低 8%。作者表示這支持提供手術。
在瑞典、挪威、美國和英國的研究者提出批評信函後，期刊編輯下令進行兩次統計審查，並要求作者比較 1,018 名接受手術的患者與 1,018 名相似的未手術患者。
2020 年 8 月的更正指出，這項比較顯示在情緒或焦慮就診、處方，或自殺未遂後的住院方面，手術都「沒有優勢」。
更正稱支持手術的結論「過強」，因為研究並未及時往前追蹤，也沒有隨機分配治療。更正也把接受手術的比例從 48% 改為 37.9%。
論文沒有被撤回。它附加說明後重新發布，作者在回覆中為手術後時間的發現辯護，並主張未手術患者不是好的比較組。
在新的比較中，接受手術的患者因焦慮接受治療的可能性稍高，自殺未遂後住院為 13 次對 7 次。這個差異很可能只是偶然，SEGM 表示這並不顯示有傷害。
多數手術是近期進行的：1,018 人中超過 75% 距 2015 年不到三年，只有 19 人是在 10 年或更久以前，因此這項研究對長期結果幾乎沒有說明。

Abstract

In October 2019, the American Journal of Psychiatry (AJP) published a study from the Karolinska Institute in Sweden, and the Yale School of Public Health which reported that “gender-affirming" surgeries for gender dysphoric patients are associated with improved mental health outcomes. Looking at mental health utilization in the year 2015, a retrospective analysis showed that the more time passed since surgery, the fewer mental services were utilized by patients, with an average 8% reduction in mental health utilization for each year following surgery. From this, the study concluded that surgery has a beneficial effect on mental health, and that benefits continue to accrue over time. However, following a reanalysis of the data, this conclusion has now been officially corrected to indicate that there is “no advantage of surgery.”

Conclusion

After reanalysis with a control group comparing gender dysphoric patients who received surgery to those who did not, no statistically significant difference was found in mental health utilization measures. The AJP correction stated the original conclusion that 'the longitudinal association between gender-affirming surgery and lower use of mental health treatment lends support to the decision to provide gender-affirming surgeries' was too strong. The Society for Evidence-Based Gender Medicine (SEGM) concluded that no mental health benefit of gender-affirming surgery was demonstrated in the corrected analysis.

Methodological limitations

Written by a group with a position: This record is SEGM's explanation, not the correction itself. SEGM argues for caution in gender medicine and notes that some of its advisers wrote the critical letters, so its framing should be read with that in mind.
New comparison was an afterthought: The surgery vs no-surgery comparison was not part of the original question. The correction notes that the groups may differ in several other ways, so the 'no difference' result is also not strong proof either way.
Comparison group mixes different people: The authors argued that people diagnosed with gender incongruence who had not had surgery include many who never wanted it. So finding no difference does not show surgery has no benefit for those who seek it, a point SEGM accepts.
Corrected, not withdrawn: The journal corrected the conclusion and reposted the article, but did not withdraw the time-since-surgery link, which the authors stood by. Saying 'the study was wrong' goes further than the formal correction.
One-year snapshot: Both analyses looked at mental health treatment in 2015 only, comparing different people at different times since surgery rather than following the same people over time. They cannot show change in any one person.
Indirect measures: Visits, prescriptions and hospital stays measure use of services, not symptoms or quality of life. Required mental health assessments before surgery may have pushed up service use around the time of surgery.
Deaths and moves abroad missed: Only people alive and living in Sweden in 2015 were included. If people died, including by suicide, after surgery, those with surgery long ago would look healthier than they were. The authors admitted this.
Patients changed over time: More recent patients were younger, more often born female and more often had other mental health problems. This alone could explain why people with older surgeries used fewer services, regardless of surgery.
Many tests, one hit: The single positive result in the original was only just clear of chance, and came alongside several other measures tested without allowing for the extra chance of a fluke, as letter writers pointed out.
Doubtful 'lost patients' claim: SEGM suggests about 90% of patients were 'lost', because only 19 had surgery before 2005 compared with 324 in an earlier Swedish study. But the study only included people diagnosed from 2005 to 2015, so people treated earlier were mostly outside the study rather than lost.
Too few suicide-related cases: Hospital stays after suicide attempts (13 vs 7) are too few to support conclusions either way, and the new comparison was too small to test this properly.

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