Table 2. Quality characteristics of the studies.
|
Author (reference) |
Dropout rate | Reasons for dropout | Confounding variables | Estimated risk of bias (e3) |
| Ainsworth et al. (22) |
— | — | n = 25 (10.12%) M–F*1 had sex reassignment surgery n = 47 (19.02%) had sex reassignment surgery and facial feminization surgery n = 28 (11.3%) had facial feminization surgery n = 147 (59.51%) had no surgery Time of survey not stated, hormone therapy |
Moderate to high: selection bias, classification bias, bias owing to deviations in interventions |
| Bouman et al. (27) |
20.51% | Non-respondents n = 6 (15.38%) Lost to follow-up n = 1 (2.56%) Deceased n = 1 (2.56%) |
27 M–F (= 87.1%) completed the QoL questionnaire, hormone therapy | Moderate to high: selection bias |
| Cardoso da Silva et al. (26)*2 |
75.26%*3 (n= 30 M–F [15.7%] excluded) |
— | Dropout rate very high, no reasons given 31 M–F (65.95%) had corrective surgery, hormone therapy |
Moderate to high: selection bias, attrition bias |
| Castellano et al. (17) |
11.76% | Non-respondents n= 8 (11.76%) | Only the domain general quality of life score and subdomains ‧sexuality and body were requested, hormone therapy | Moderate to high: selection bias Moderate: detection bias |
| Jokic-Begic et al. (18) |
25% | Lost to follow-up n = 1 (12.5%) Refused participation n = 1 (12.5%) |
Very small study population, socioeconomic and clinical circumstances, psychotherapy, hormone therapy | Moderate to high: selection bias |
| Kuhn et al. (19) |
— | — | No detail on interventions in the control group,no separate data analysis for M–F and F–M, hormone therapy | Moderate to high: selection bias, bias owing to deviations in interventions |
| Lindqvist et al. (23)*2 |
77.37%*4 | Deceased or moved without changing address and entry in residents‘ register | Very high dropout rate, only 17 patients completed the questionnaire at all 4 follow-up points, hormone therapy | Moderate to high: selection bias, attrition bias |
| Papadopulos et al. (29) |
61.15% | Unavailable/incorrect phone number n = 38 (31.40%) Refused participation n = 14 (11.57%) Quesionnaire not completed n = 22 (18.18%) |
Inclusion criteria: only patients who had had corrective surgery or those who did not require such surgery, hormone therapy | Moderate to high: selection bias |
| Parola et al. (20) |
— | — | Hormone therapy | Moderate to high: selection bias |
| van der Sluis et al. (28) |
62.5% | Non-respondents n = 6 (25%) Lost to follow-up n = 3 (12.5%) Deceased n = 5 (20.84%) Refused participation n = 1 (4.16%) |
Small study population Secondary vaginoplasty Hormone therapy |
Moderate to high: selection bias |
| Weyers et al. (24) |
28.57% | Non-respondents n= 17 (24.29%) Refused participation n=3 (4.29%) |
Hormone therapy | Moderate to high: selection bias |
| Yang et al. (25) |
— | — | n = 73 (34.92%) had facial feminization surgery n = 43 (20.57%) had breast augmentation surgery Only n = 4 (1.91%) had sex reassignment surgery Socioeconomic and clinical circumstances Hormone therapy in only n = 37 (17.7%) |
Moderate to high: selection bias, bias owing to deviations in interventions |
| Zimmermann et al. (21) |
55.56% | Non-respondents n = 45 (50%) Incomplete questionnaire n = 3 (3.34%) Inclusion criteria not met n = 2 (2.23%) |
Absolute values from FLZ questionnaire not shown, only p-values reported, no separate evaluation of FLZ questionnaire for F–M and M–F, hormone therapy | Moderate to high: selection bias |
*1 M–F male to female; F–M female to male, reassignment surgery
*2 Prospective study design
*3 Of originally 190 participants, n = 160 (84.21%) completed the questionnaire preoperatively and n = 47 (24.73%) postoperatively
*4 Out of a total of 190 study participants, n = 146 (76.84%) completed the questionnaire preoperatively, n = 108 (56.84%) 1 year postoperatively, n = 64 (33.68%) 3 years postoperatively, and n = 43 (22,63%) 5 years postoperatively. Most of the 190 participants completed the questionnaire at least at two follow-up points.