Determination of sexual health is challenging, especially in Asian men who are often reluctant to undergo evaluation of sexual function. The response rate among participants to questionnaires designed to survey sexual function has been reported to range from 22.5 % to 81 % [
8,
11,
16]. In our study, however, the response rate was 85 %. The introductory letters written by the surgeon who performed the LDLT procedures most likely contributed to the relatively high compliance rate in our study. The etiology of sexual dysfunction is multi-factorial and ESLD is one of many factors associated with the disorder. Liver transplantation restores liver function and should, theoretically, result in improvements in sexual function [
8]. However, immunosuppressive drugs, which are key to survival after liver transplantation, are known to impair sexual function [
17]. Alterations in the hypothalamic-pituitary-gonadal axis, changes in estrogen-over-androgen ratio, and altered sex hormone transport have been shown to cause hypogonadism in patients with impaired liver function [
16,
18,
19]. Decreased testosterone level, libido, testis size and even infertility have been reported in patients with cirrhosis [
3,
20]. Foresta et al. reported decreased sex hormone binding protein levels and higher free testosterone in serum in patients after OLT, which may explain the improvement in physiological function after the operation, even under immunosuppressive therapy [
4]. Park et al. reported that up to 60 % of men reported no improvement in erectile function after OLT [
10]. Klein and colleagues reported improvement in sexual function including erectile function, sexual satisfaction and sexual desire and a statistical trend in improvement in IIEF scores after liver transplant [
21]. In our study, we found that nearly half of the patients reported improvement in erectile function. Many factors contribute to ED, including drugs, neurogenic disorders, cavernosal disorders, hormones, psychological causes, surgery, aging, and diabetes [
22]. In our study, higher IIEF-5 scores were associated with absence of hypogonadism after the operation. That is, improvement in erectile function after liver transplantation is mainly hormone related. Theoretically, irreversible damage of the hypothalamic-pituitary-gonadal axis by long-term consumption of alcohol implies the low possibility of improvement in sexual function after LDLT [
23]. However, Huyghe E et al. reported no higher risk of erectile dysfunction in patients with end-stage liver disease secondary to alcohol consumption [
8]. Burra et al. also reported that there was no significantly lower trend in IIEF score in patients with alcohol-induced ESLD [
3]. Sorrell and Brown found that 40 % of patients developed erectile dysfunction and 25 % reported having a lower level of sexual satisfaction after liver transplantation [
16]. Ho et al. reported that 32 % of patients developed de novo sexual dysfunction after OLT [
24]. Cardiovascular disease, post-transplantation diabetes, alcohol abuse, antidepressants and angiotensin II receptor blockers have been shown to be associated with new onset erectile dysfunction after liver transplantation [
8]. In our study, 12 % (n = 7) of our patients reported a decrease in erectile function after LDLT. The low incidence of de novo erectile dysfunction might be due to the relatively short follow-up period in our study.
There are several limitations in this study. First, immunosuppressive regimens after transplantation were not consistent throughout the study population. Therefore, we were not able to take pharmacologic factors into account. Second, our findings are limited by the relatively small sample size and short follow-up period. Third, we did not measure serum testosterone levels and therefore we do not have laboratory data to support the change in prevalence of hypogonadism. Nonetheless, to the best of our knowledge, this is the first study to compare changes in sexual function before and after LDLT. Large-scale studies with longer follow-up periods are needed to clarify the role liver transplantation plays in sexual function.