Sexual Dysfunction And Activity Avoidance in Female Kidney Transplant Patients

Panpan Xiao¹ | Min Liu² | Lina Cui² | Siqing Ding^2,3 | Jianfei Xie² | Andy SK Cheng⁴

Contact: joanna.jia@wecistanche.com / WhatsApp: 008618081934791

Abstract

Sexual dysfunction is common after kidney transplantation and has an adverse effect on patients’ quality of life. This paper aims to evaluate the female sexual function, activity avoidance, and kidney function among a convenience sample of patients who had a kidney transplant. A cross-sectional study was conducted that included 250 patients who had undergone a kidney transplant procedure >3 months ago, from multiple transplant centers and answered a self-reported sociodemographic questionnaire, the female version of the Arizona Sexual Experience Scale, and the Tampa Scale for Kinesiophobia-13. A correlation was found between sexual function and activity avoidance (r = .361, p < .001, n = 250) as well as between activity avoidance and kidney function (r =0 .198, p = .012, n = 250). Less education, having no child, post-transplant time for <36 months, and smoking (active and passive) were risk factors for female sexual dysfunction after kidney transplantation. The results suggest that physicians that the importance of recognizing the relationship between fear of sexual activity and sexual function and that they should provide patients with more education and guidance on post-transplant sexual behaviors.

KEYWORDS: activity avoidance, kidney transplant, sexual dysfunction

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1. INTRODUCTION

Kidney transplantation (KT) has become the most ideal alternative therapy for patients with end-stage renal disease (ESRD) compared to dialysis, with the 10-year survival rate for patients with KT increasing to 85%–90%.1,2 Recently, there have been attempts from nephrologists and sociologists to find solutions that improve the quality of life for kidney transplant patients,3 such as increasing support from society, family, and medical staff,4 and providing exercise training plans.5

Sexual life is an important determinant of quality of life.6 A multinational cross-sectional study with 1472 patients with ESRD showed that approximately 85% of them reported sexual dysfunction (SD) during dialysis.7 Although KT, to some extent, improves sexual health (eg, libido) due to normalization of the hormonal disturbances,8,9 some studies with prospective cohort designs have shown that some aspects of sexual function do not improve after KT, and a significant number of patients may even experience worsening of sexual function.10,11 For instance, a literature review concluded that 60.9% of kidney transplant patients reported decreased interest or ability to perform or respond sexually.12 A qualitative interview showed that SD has been reported in approximately 50% of both men and women after transplantation.13 In addition to the quality of life, SD in patients with KT can also affect medication compliance14 and relationship satisfaction15 and can be associated with psychological effects (eg, depression).16 Nevertheless, sexual health is often ignored by health professionals encompassing physicians, nurses, and nephrologists during the consultation, especially after transplantation.17

In China, the prevalence of chronic kidney disease was estimated to be approximately 10.8%,18, and ESRD, without treatment, would progress and eventually cause death. However, KT, as the most effective therapy for ESRD, is exceptionally limited to the extreme scarcity of matched kidney sources.19 Therefore, patients receiving a KT significantly cherish this hard-won opportunity, and they have heightened anxiety concerning their graft and fear of movement and minimize or avoid physical activity.20 The majority do not meet the recommended amount or required type of physical activity, and both longitudinal studies20 and qualitative interviews21 have shown that the most important source of activity avoidance was fear of losing the graft and those with higher fear levels also tend to have worse quality of life.22 Moreover, it has been suggested in the literature that the physiological changes caused by sexual behavior are similar to those caused by exercise, with one sexual activity approximately equal to moderate-intensity physical exercise, such as vigorous walking.23 Therefore, the beliefs of fear of movement may prevent kidney transplant patients from having sex and subsequently impact the sexual quality of life.

At present, the etiology of SD in kidney transplant patients remains unclear and may be caused by physiological factors (eg, drug side effects, comorbidities, hormone disturbances, autonomic neuropathy) or psychological factors,24 and the majority of studies on sexual dysfunction in kidney transplant patients have focused on male patients.25–27 Our current study's objectives were to assess sexual dysfunction in female kidney transplant patients and the relationship between sexual function, activity avoidance, and kidney function to further elucidate the mechanism of female sexual dysfunction after transplantation. We also analyzed the relationships between some sociodemographic and clinical variables and sexual function.

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2. MATERIALS AND METHODS

2.1. Participants

The Kidney Transplant Center in the six Chinese Tertiary Hospitals followed over 700 patients between June and November 2019. Only female patients older than 18 years of age were able to communicate in Chinese, and those who had undergone kidney transplant surgery ≥3 months were recruited. All the participants received notification of research information, an informed consent waiver to be signed, and the self-reported questionnaires. Patients answered the questionnaires on paper in the absence of healthcare professionals’ supervision or counseling. No compensation was given for participating in this study. To participate, patients returned the signed informed consent forms and the completed questionnaires.

3. MEASURES

3.1. Sociodemographic data

The researchers constructed and applied a brief questionnaire to assess participants’ sociodemographic and clinical data, encompassing their age (classified by 18–44, 45–59, and ≥60 years old), marital status (classified by unmarried, married, and widowed/divorced), educational status (classified by middle school or below, high school, college or bachelor, and master or above), monthly income (classified by <3000, 3000–6000, 6000–10 000, and ≥10 000￥), number of children (0 or ≥1), and cigarette smoking (active and passive, yes or no), as for clinical variables, including their major causes of end-stage renal disease (ESRD, classified by chronic glomerulonephritis, polycystic renal disease, diabetic nephropathy, and other nephropathies), number of transplants (1 or ≥2 times), dialysis types (hemodialysis or peritoneal dialysis), post-transplant time (<36 months or ≥36 months), kidney graft characteristics (living or deceased donor), comorbidities (hypertension, diabetes mellitus, obesity, and anemia), and serum creatinine levels (reported the latest measurement by participants).

3.2. Sexual function

The Arizona Sexual Experience Scale (ASEX)28 (Cronbach's α = 0.91) is a five-item self-reported measurement instrument designed to assess sexual function. It includes both male and female versions, of female measures the quality of functioning in terms of five questions, each representing one domain: (i) sexual drive, (ii) sexual arousal, (iii) vaginal lubrication, (iv) ability to reach orgasm, and (v) sexual satisfaction from orgasm. Participants were asked to rate on a 6-point Likert-type scale ranging from 1 (no impairment) to 6 (complete impairment). The ASEX is interpreted based on a total score and/or assessment of scores on individual items with lower scores indicating better sexual functioning. SD was defined as a total score of ≥19 or a score ≥5 on any one item or a score ≥4 on any three items, with any other score indicating no SD. In the current study, a Chinese version of the ASEX29 with Cronbach's α of 0.89 was used.

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3.3. Activity avoidance

The Tampa Scale for Kinesiophobia-13 (TSK-13),22,30 adapted from the original 17-item TSK scale with four entries removed, was used to assess the level of kinesiophobia in kidney transplant patients. Its entries were rated on a 4-point Likert-type scale ranging from 1 (strongly disagree) to 4 (strongly agree), with higher scores indicating stronger fear/avoidance beliefs. The Chinese-validated version of the TSK-13 (Cronbach's alpha = 0.82) presented good psychometric properties.31

3.4. Procedures

The study design was descriptive, observational, and cross-sectional, used a convenience sample, and was approved by the Ethics Committee of The Third Xiangya Hospital of Central South University.

3.5. Statistical Analysis

The Kolmogorov-Smirnov test was used to test the distributions of the data collected. Data with a non-normal distribution are expressed as the median (Q1-Q3). Normally distributed data were expressed as the mean and the standard deviation (SD) and tested by unpaired t-tests, whereas categorical variables were expressed as frequency and percentage and tested by chi-squared (χ2 ) analysis or nonparametric test. Pearson's correlation analysis was used in the analysis of paired continuous variables if they fit a normal distribution, otherwise, Spearman's correlation analysis was used. Risk factors for sexual dysfunction (ASEX total score of ≥19 or a score ≥5 on any one item or a score ≥4 on any three items) were determined using logistic regression models with backward variable selection (Wald test). All factors with a p-value < .05 were included as candidate variables in the univariate analyses (ie, age, educational status, having childbearing or not, smoking, dialysis types, and post-transplant time). The β coefficients, odds ratios, and p-values were calculated. p-Values < .05 (2-sided) were considered statistically significant. Statistical analysis was performed using SPSS for Windows (IBM SPSS Statistics version 24; Chicago, IL, USA).

4. RESULTS

Between July and September 2019, the kidney transplant center's nursing staff invited a total of 700 patients to participate in this study before a clinical visit. The response rate was 40.3% (n = 282 patients), and finally, 250 questionnaires were validated. The median age of the participants was 39 years old (ranging from 18 to 69 years). The sociodemographic and clinical variables are displayed in Table 1. Approximately half of the participants were young adults (18–44 years old, 55.2%, n = 138) and did not have children (49.2%, n = 123). Most participants (78.0%, n = 195) reported being married. Chronic glomerulonephritis (70.4%, n = 176) was the most frequently reported major cause of ESRD. Most of the patients had undergone hemodialysis before receiving a kidney transplant (82.0%, n = 205) and received a deceased donor (90.0%, n = 225) (Table 1).

The ASEX scale was used to evaluate sexual function and presented good and excellent internal consistency (total score was 18.23 ± 4.46, Cronbach's alpha = 0.90). The scores of sexual drive, sexual arousal, vaginal lubrication, ability to reach orgasm, and sexual satisfaction were 3.62 ± 0.93, 3.59 ± 0.98, 3.78 ± 1.22, 3.79 ± 1.13, and 3.44 ± 1.01, respectively. The TSK-13 was used to investigate the activity avoidance beliefs (total score was 33.16 ± 5.00). Serum creatinine levels can reflect the recovery of kidney function after KT, and its median was 85.0 (77.0–100.5) (Table 2).

4.1. Sexual function

Sexual dysfunction was diagnosed in 61.6% (n = 154) of patients who presented a total score ≥19, a score ≥5 on any one item, or a score ≥4 on any three items. In the logistic regression, educational status with middle school or below, having no children, post-transplant time for <36 months, and smoking (active and passive) were risk factors (Table 3).

4.2. Correlations between sexual function, activity avoidance, and kidney function

A positive correlation was identified between sexual function and activity avoidance (r = .361, p < .001, n = 250) and between activity avoidance and kidney function (r = .198, p = .012, n = 250). No association was found between sexual function and kidney function (r = 0.106, p = .095, n = 250) (Table 4).

5. DISCUSSION

The main objectives of this study were to assess sexual function concerns among female kidney transplant patients and the relationship between sexual function, activity avoidance, and kidney function, as well as demographic and clinical factors associated with sexual function. We found that the prevalence of female sexual dysfunction (FSD) in kidney transplant patients was 61.6% and that educational status, having children, post-transplant time, and smoking (active and passive) were the identified influencing factors. We also found that activity avoidance was associated with sexual dysfunction and kidney function, but sexual dysfunction was not associated with kidney function. Many studies on sexual dysfunction in kidney transplant patients have focused on males.25–27 Our study, to the best of our knowledge, is the first to show that post-transplant time and activity avoidance are associated with sexual dysfunction in female kidney transplant patients, which provides a theoretical basis for improving the sexual quality of life of those populations.

We observed a high prevalence of FSD in kidney transplant patients, particularly the orgasmic disorders, and the rates identified in this study were different from those reported in earlier studies.13,32 Using different scales for evaluating sexual function after KT, Basok et al.32 reported that the prevalence of FSD was 50% that arouse dysfunction was the most serious by using the Female Sexual Function Index (FSFI). Another study from Turkey reported that the prevalence of FSD was 73.9%, particularly sexual desire disorder.33 Although sex hormone levels will gradually return to nearly normal after KT,34 there are still a significant number of patients who experience worsening sexual functioning.10,11 Empirical studies have shown that SD has been reported in approximately 50% of kidney transplant patients and has several adverse effects on quality of life.17 However, compared with male patients, researchers at home and abroad pay far less attention to the FSD and reproductive concerns after KT16,25,35; moreover, a study by Cabral et al.36 found that only 34.6% of female kidney transplant patients referred to discuss sexual issues with their physicians, whereas 73.1% stated it would have been important. These results indicated that more attention and strategies are required from healthcare providers to manage FSD after transplantation.

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Our study also identified several risk factors for FSD in kidney transplant patients and we found that FSD was inversely related to education levels, consistent with these previous studies.32,33 Our study indicated that having no children was associated with worsening sexual function, which is the opposite of Bosok's study32 results. In his study, patients with FSD included 46 dialysis, 20 KT, and 20 controls, while our study only included females with KT. Second, over 50% of patients enrolled in our study were young adults and had no children. Fertility plays a significant role in carrying on the family line due to the influence of traditional Chinese culture, and having no children brings the patient significant pressure,37 which may have an effect on the quality of sexual life. Healthcare providers need to focus on young kidney transplant patients with no children and provide them with information support about fertility and sexuality.

In the early period after KT, patients focus almost all of their attention on the kidney allograft and are afraid to perform physical activities including sexual behavior to avoid damaging the graft. Antonucci et al25 demonstrated a higher rate of erectile dysfunction in male kidney transplant patients. We divided post-transplantation time into <36 and ≥36 months according to Mota's stidies25 and found that post-transplantation time was associated with FSD. This association was observed in Spirito's study for male kidney transplant patients,27 indicating that healthcare workers should also provide sex-related guidance in the early period of transplantation, in addition to focusing on allograft kidney function. Our study also showed that smoking (active and passive) was strongly associated with FSD in kidney transplant patients. Previous studies have also shown a relationship between both variables in female medical students.38,39 Nevertheless, Costa et al40 tested whether smoking status is associated with FSD during intercourse and whether nicotine dependence rather than smoking status is related to FSD; they found that, in community women, smoking is unrelated to female sexual function, but suggested the possibility of an inverse U-shaped relationship between smoking and libido. This may explain our result because the composition of our female smokers was both active and passive smokers. It is necessary for scholars to conduct longitudinal research to further clarify the relationships between smoking and sexual function in female kidney transplant patients.

A strong positive correlation was identified between sexual function and activity avoidance. We found that this association was identified in a study of chronic nonspecific low back pain.41 Since the internal iliac artery is shallow and easily anastomosed with the graft vessels and its blood flow vessel meets the needs for blood perfusion flow of the graft kidney, generally speaking, the graft kidney is usually transplanted in the fossa iliac on one side of the patient's lower abdomen, which is adjacent to the sexual organ (ie, vagina and testis). Many patients are found afraid to have sex for fear of colliding or damaging the graft through physicians’ interviews with them,20,42 thereby presenting a low frequency of sexual intercourse after KT.15 Clinicians should explain when patients can have sex after KT and which positions are more favorable for sexual activity and protecting the graft.43 Unfortunately, healthcare professionals frequently do not discuss this topic with their patients, especially females,43–45, and/or they have poor knowledge about sexual function in kidney transplant patients and are not always able to properly interpret this kind of dysfunction in patients complaining of SD.17 We emphasize the need to incorporate adequate knowledge on the sexual health of kidney transplant patients into residence training, in order to raise healthcare practitioners’ awareness.

Our study showed no association between better sexual function and lower serum creatinine levels, whereas this association was observed among patients on hemodialysis46 and peritoneal dialysis.47 In a biopsychosocial model, the etiology of SD is often multifactorial, such as side effects due to medication, hormone disturbances, changes in body shape, and psychosocial factors.24,48 Thus, we must acknowledge that, as a cross-sectional study, this research cannot evaluate the individual variability of patients' psychological factors on sexual function changes before and after KT, and the relationships between creatinine and sexual function in kidney transplant patients need to be further explored.

One limitation of our study concerns the generalization of the results, because the study is a cross-sectional design, and we could not explain the sexual function and activity avoidance over time. Our sample was composed of participants with residents in central and southern China and the nonresponse rate was high, and hence, observations and conclusions should be treated with caution. Additionally, there was no control group (with age-matched nontransplant ESRD), resulting in this study being unable to reveal the actual changes in sexual function before and after KT. Moreover, a different study design (ie, longitudinal study or qualitative study based on interviews) should be used to clarify the multifactorial aspects (ie, physiological, hormonal, psychological, and subjective perception) that impact sexual function in female kidney transplant patients to improve the research level in this field.

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6. CONCLUSION

This study showed a high prevalence of sexual dysfunction in female patients who underwent kidney transplantation in central and southern China. Activity avoidance after undergoing kidney transplantation is associated with worse sexual function. Patients with higher beliefs of fear of movement may be less likely to engage in sexual activity, which impacts the sexual quality of life. Given this association, healthcare professionals must briefly provide sexual information or behavior guidance during preoperative and post-transplant consultation on sexual health to avoid patients’ having heightened anxiety about the graft stopping or reducing having sex, and improve the overall quality of life.

ACKNOWLEDGMENT

We acknowledge all the patients involved in this study for their cooperation.

CONFLICT OF INTEREST

The authors declared no financial conflict of interest.

AUTHOR CONTRIBUTION

Study design: Xiao P, Liu M, and Xie J; questionnaire survey and data analysis: Cui L, Xiao P, and Liu M; manuscript preparation: Liu M and Xiao P. manuscript revision: Xie J, Ding S, and Andy SK Cheng.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.

REFERENCES:
1. Almasi-Hashiani A, Rajaeefard AR, Hassanzade J, et al. Graft survival rate of renal transplantation: a single-center experience, (1999–2009). Iran Red Crescent Med J. 2011;13(6):392-397.
2. Kang SS, Park WY, Jin K, Park SB, Han S. Characteristics of Recipients With 10 or More Years of Allograft Survival in Deceased Donor Kidney Transplantation. Transplant Proc. 2018; 50(4):1013-1017.
3. Chen WC, Chen CH, Lee PC, Wang WL. Quality of life, symptom distress, and social support among renal transplant recipients in Southern Taiwan: a correlational study. J Nurs Res. 2007;15(4):319-329.
4. Dweib K, Jumaa S, Khoury M, Hallak H. Quality of life for kidney transplant Palestinian patients. Saudi J Kidney Dis Transpl. 2020;31(2):473-481.
5. Oguchi H, Tsujita M, Yazawa M, et al. The efficacy of exercise training in kidney transplant recipients: a meta-analysis and systematic review. Clin Exp Nephrol. 2019;23(2):275-284.
6. Wilmoth MC. Sexuality: a critical component of quality of life in chronic disease. Nurs Clin North Am. 2007;42(4):507-514.
7. Strippoli GF, Vecchio M, Palmer S, et al. Sexual dysfunction in women with ESRD requiring hemodialysis. Clin J Am Soc Nephrol. 2012;7(6):974-981.
8. Filocamo MT, Zanazzi M, Li MV, et al. Sexual dysfunction in women during dialysis and after renal transplantation. J Sex Med. 2009;6(11):3125-3131.
9. Wang GC, Zheng JH, Xu LG, et al. Measurements of serum pituitary-gonadal hormones and investigation of sexual and reproductive functions in kidney transplant recipients. Int J Nephrol. 2010;2010:612126.
10. Raggi MC, Siebert SB, Friess H, et al. Sexual and relationship functioning before and after renal transplantation: a descriptive study with patients and partners. Scand J Urol Nephrol. 2012;46(6):431-436.
11. Mirone V, Longo N, Fusco F, et al. Renal transplantation does not improve erectile function in hemodialysis patients. Eur Urol. 2009;56(6):1047-1053.
12. Pertuz W, Castaneda DA, Rincon O, Lozano E. Sexual dysfunction in patients with chronic renal disease: does it improve with renal transplantation? Transplant Proc. 2014;46(9):3021-3026.
13. Diemont WL, Vruggink PA, Meuleman EJ, et al. Sexual dysfunction after renal replacement therapy. Am J Kidney Dis. 2000;35(5):845-851.
14. Kenawy AS, Gheith O, Al-Otaibi T, et al. Medication compliance and lifestyle adherence in renal transplant recipients in Kuwait. Patient Prefer Adherence. 2019;13:1477-1486.
15. Einollahi B, Tavallaii SA, Bahaeloo-Horeh S, et al. Marital relationship and its correlates in kidney recipients. Psychol Health Med. 2009;14(2):162-169.
16. Mota RL, Fonseca R, Santos JC, et al. Sexual Dysfunction and Satisfaction in Kidney Transplant Patients. J Sex Med. 2019;16(7):1018-1028.
17. van Ek GF, Krouwel EM, van der Veen E, et al. The Discussion of Sexual Dysfunction Before and After Kidney Transplantation From the Perspective of the Renal Transplant Surgeon. Prog Transplant. 2017;27(4):354-359.
18. Zhang L, Wang F, Wang L, et al. Prevalence of chronic kidney disease in China: a cross-sectional survey. Lancet. 2012;379(9818):815-822.
19. Shang W, Shen Y, Gao S, et al. Comparison of HLA-A, -B and -DRB1 Loci Polymorphism between Kidney Transplants of Uremia Patients and Healthy Individuals in Central China. PLoS One. 2016;11(10):e0165426.
20. Dontje ML, de Greef MH, Krijnen WP, et al. Longitudinal measurement of physical activity following kidney transplantation. Clin Transplant. 2014;28(4):394-402.
21. Luk WS. The HRQoL of renal transplant patients. J Clin Nurs. 2004;13(2):201-309.
22. Zelle DM, Corpeleijn E, Klaassen G, et al. Fear of Movement and Low Self-Efficacy Are Important Barriers in Physical Activity after Renal Transplantation. PLoS One. 2016;11(2):e0147609.
23. Frappier J, Toupin I, Levy JJ, Aubertin-Leheudre M, Karelis AD. Energy expenditure during sexual activity in young healthy couples. PLoS One. 2013;8(10):e79342.
24. Rathi M, Ramachandran R. Sexual and gonadal dysfunction in chronic kidney disease: Pathophysiology. Indian J Endocrinol Metab. 2012;16(2):214-219.
25. Antonucci M, Palermo G, Recupero SM, et al. Male sexual dysfunction in patients with chronic end-stage renal insufficiency and in renal transplant recipients. Arch Ital Urol Androl. 2016;87(4):299-305.
26. Biebel MG, Burnett AL, Sadeghi-Nejad H. Male Sexual Function and Smoking. Sex Med Rev. 2016;4(4):366-375.
27. Spirito L, Manfredi C, Carrano R, et al. Impact of Kidney Transplantation on Male Sexual Function: Results from a Ten-Year Retrospective Study. J Sex Med. 2020;17(11):2191-2197.
28. McGahuey CA, Gelenberg AJ, Laukes CA, et al. The Arizona Sexual Experience Scale (ASEX): reliability and validity. J Sex Marital Ther. 2000;26(1):25-40.
29. Wen JK, Hung CF, Chen SW, Jing JH, Chu YJ. Validity and reliability of Arizona Sexual Experiences Scale Chinese Version (ASEX-CV) in
the clinical study of outpatients with depressive disorder and sexual dysfunction. 2006:119-120.
30. Swinkels-Meewisse EJ, Swinkels RA, Verbeek AL, Vlaeyen JW, Oostendorp RA. Psychometric properties of the Tampa Scale for kinesiophobia and the fear-avoidance beliefs questionnaire in acute low back pain. Man Ther. 2003;8(1):29-36.
31. Wei X, Xu X, Zhao Y, et al. The Chinese version of the Tampa Scale for Kinesiophobia was cross-culturally adapted and validated in patients with low back pain. J Clin Epidemiol. 2015;68(10):1205-1212.
32. Basok EK, Atsu N, Rifaioglu MM, et al. Assessment of female sexual function and quality of life in predialysis, peritoneal dialysis, hemodialysis, and renal transplant patients. Int Urol Nephrol. 2009;41(3):473-481.
33. Kurtulus FO, Salman MY, Fazlioglu A, Fazlioglu B. Effects of Renal Transplantation on Female Sexual Dysfunction: Comparative Study With Hemodialysis and a Control Group. Transplant Proc. 2017;49(9):2099-2104.
34. Akbari F, Alavi M, Esteghamati A, et al. Effect of renal transplantation on sperm quality and sex hormone levels. Bju Int. 2003;92(3):281-283.
35. Eckersten D, Giwercman A, Pihlsgard M, Bruun L, Christensson A. Impact of Kidney Transplantation on Reproductive Hormone Levels in Males: A Longitudinal Study. Nephron. 2018; 138(3):192-201.
36. Cabral JF, Cavadas V, Silva RM, et al. Female sexual function and depression after kidney transplantation: comparison between deceased- and living-donor recipients. Transplant Proc. 2015;47(4):989-991.
37. Loke AY, Yu PL, Hayter M. Experiences of sub-fertility among Chinese couples in Hong Kong: a qualitative study. J Clin Nurs. 2012;21(3–4):504-512.
38. Wallwiener CW, Wallwiener LM, Seeger H, et al. Sexual Function, Contraception, Relationship, and Lifestyle in Female Medical Students. J Women's Health (Larchmt). 2017;26(2):169-177.
39. Wallwiener CW, Wallwiener LM, Seeger H, et al. Prevalence of sexual dysfunction and impact of contraception in female German medical students. J Sex Med. 2010;7(6):2139-2148.
40. Costa RM, Peres L. Smoking is unrelated to female sexual function. Subst Use Misuse. 2015;50(2):189-194.
41. Ferrari S, Vanti C, Frigau L, et al. Sexual disability in patients with chronic non-specific low back pain-a multicenter retrospective analysis. J Phys Ther Sci. 2019;31(4):360-365.

42. Tsujimura A, Matsumiya K, Tsuboniwa N, et al. Effect of renal transplantation on sexual function. Arch Androl. 2002;48(6):467-474.

43. Josephson MA, McKay DB. Women and transplantation: fertility, sexuality, pregnancy, contraception. Adv Chronic Kidney Dis. 2013;20(5):433-440.

44. Schipper K, Abma TA, Koops C, et al. Sweet and sour after renal transplantation: a qualitative study about the positive and negative consequences of renal transplantation. Br J Health Psychol. 2014;19(3):580-591.
45. Schipper K, Abma TA. Coping, family, and mastery: top priorities for social science research by patients with chronic kidney disease. Nephrol Dial Transplant. 2011;26(10):3189-3195.
46. Hekmat R, Maghsudloo F, Mohebi M, et al. A study of the main determinants of sexual dysfunction in women aged 15–45 years on chronic hemodialysis. Saudi J Kidney Dis Transpl. 2016;27(5):916-920.
47. Azevedo P, Santos R, Duraes J, et al. Sexual dysfunction in men and women on peritoneal dialysis: Differential link with metabolic factors and quality of life perception. Nefrologia. 2014;34(6):703-709.
48. Finkelstein FO, Shirani S, Wuerth D, Finkelstein SH. Therapy Insight: sexual dysfunction in patients with chronic kidney disease. Nat Clin Pract Nephrol. 2007;3(4):200-207