ORAL VERSUS TRANSDERMAL ESTROGEN IN TURNER SYNDROME: A SYSTEMATIC REVIEW AND META-ANALYSIS

OBJECTIVE: To conduct a systematic review and meta-analysis comparing transdermal estrogens (TDEs) versus oral estrogens (OEs) in Turner syndrome (TS).

RESULTS: Of 845 candidate references, 4 studies were included. Both OEs and TDEs were associated with an increase in whole-body bone mineral density (BMD) z-score, with TDE therapy displaying a greater increase. OEs were associated with higher fasting glucose and total cholesterol. Both OEs and TDEs reduced low-density lipo-protein cholesterol (LDL-C) and increased high-density lipoprotein cholesterol (HDL-C), with OEs providing a more favorable effect. The use of 17-β estradiol was associated with a higher total cholesterol and lower LDL-C than TDE. No statistically significant difference was found between OEs and TDEs in body mass index, fat mass, fat free mass, insulin-like growth factor 1, insulin-like growth factor binding protein 3, fasting insulin, triglycerides, estradiol, or estrone levels.

METHODS: Randomized trials and observational comparative studies with a minimal follow-up of 6 months for skeletal and metabolic outcomes and serum hormone changes were included. Outcomes were pooled with a random effects model and are reported as mean differences between OE and TDE groups and 95% confidence intervals (CIs).

CONCLUSION: In girls with TS, TDEs may be associated with a more beneficial effect on fasting glucose, cholesterol, and whole-body BMD. However, OEs have a more favorable impact on LDL-C and HDL-C. 17-β estradiol has a more favorable effect on LDL-C.

ABBREVIATIONS: BMI = body mass index BMD = bone mineral density CI = confidence interval HDL-C = high density lipo-protein-cholesterol IGF-1 = insulin-like growth factor 1 IGF-BP3 = insulin-like growth factor binding protein 3 LDL-C = low density lipoprotein-cholesterol MD = mean difference OE = oral estrogen RCT = randomized controlled trial TDE = transdermal estrogen TS = Turner syndrome.