Mateu Arrom et al. BMC Women’s Health (2021) 21:63 https://doi.org/10.1186/s12905-021-01213-8 RESEARCH ARTICLE Open Access Development and validation of a short version of the Female Sexual Function Index in the Spanish population Laura Mateu Arrom1, Montserrat Girabent‑Farrés2*, Mónica González3, Joan Palou4, Carlos Errando‑Smet5 and Inés Ramírez‑García6 Abstract Background: The Female Sexual Function Index (FSFI) is a commonly used scale for the assessment of female sexual function. Our aim was to develop and validate a Spanish short version of the FSFI. Methods: A parallel exploratory, sequential mixed-methods approach was used, involving 2 sites. The process con‑ sisted of 2 steps: (1) cognitive and content validation of the previously translated FSFI in the Spanish population, both through a focus group; and item selection based on the difficulty and discrimination parameters using item response theory (IRT), thereby obtaining a short version of the scale (sFSFI-sv); (2) assessment of test–retest reliability (intraclass correlation coefficient, ICC) of the sFSFI-sv. The presence or absence of a sexual disorder variable based on clinical interview was used on the Receiver Operating Characteristic (ROC) to establish the cut off point whose Area Under the Curve (AUC) based on sensibility and specificity was maximum. Results: Specific modifications of the FSFI were made according to the focus group results. 114 women were included for IRT analysis. The initial IRT model pointed to the exclusion of items 1, 2, 5, 11, 18, and 19 (S-χ2 p < 0.001). Items 3, 9, 11, and 14 showed the best discrimination and difficulty parameters. On the basis of the IRT and focus group results, items 1, 3, 9, 12, 16, and 17 were included in the final sFSFI-sv. sFSFI-sv showed good reliability (ICC 0.91) in a group of 93 women. A total score ≤ 18 could indicate a higher risk of sexual disorder (sensitivity: 81.0%, specificity: 73.3%). Conclusion: A focus group and the IRT analysis allowed the development of a 6-item Spanish version of the FSFI, which showed good reliability in a group of Spanish women. Keywords: Female sexual function index, Spanish FSFI, Validity and reliability, Scale, Sexual dysfunction Background including anatomical, hormonal, and neurological fac- Sexuality is a key component in women’s quality of life tors, pelvic dysfunction, medications or drug abuse, and and closely related to their psychosocial wellbeing [1, 2]. psychological or socio-cultural factors [4]. Female sexual dysfunction (FSD) may be present in 19%– Despite its high prevalence, FSD continues to be under- 50% of women [3] and can result from a variety of causes, recognized and undertreated [5, 6], because few women seek help and most health care professionals do not openly ask female patients about their sexual function [4]. *Correspondence: lmateuar@gmail.com 2 As sexual dysfunction is a self-reported condition, direct Department of Physioterapy, School of Health Sciences, TecnoCampus- Pompeu Fabra University, C/Mallorca, 198 4º2ªD, 08036 Mataró, Barcelona, questioning by clinicians about sexual health is crucial in Spain order to identify FSD appropriately [4]. However, it may Full list of author information is available at the end of the article not be easy to talk directly to women about their sexual © The Author(s) 2021. 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The Creative Commons Public Domain Dedication waiver (http://creat​iveco​ mmons​.org/publi​cdoma​in/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Mateu Arrom et al. BMC Women’s Health (2021) 21:63 Page 2 of 8 lives and to decode their answers [4]. Thus, a standard- functioning [7, 8]. As no FSFI versions validated in the ized validated scale assessing the multiple domains of Spanish population were available at the time when the female sexual function is a valuable tool. study was started, we conducted cognitive validation of In 2000, Rosen et al. developed the Female Sexual the Spanish version of the FSFI translated by Blümel et al. Function Index (FSFI) scale [7], consisting of 19 items in [11]. This version was chosen because (a) the authors six domains, with the twin aims of providing a tool that reported a correct backward translation technique to would allow proper assessment of the multiple domains obtain the Spanish translation from the original Eng- of women’s sexual function and initiating and promot- lish version and (b) this version was already in common ing research in the field of female sexuality. The FSFI has use in our routine clinical practice and a priori women been shown to have good psychometric properties [8, 9] showed a good comprehension of all the items. and has been used to assess sexual function in women Cognitive validation of the FSFI was carried out by suffering from diverse medical conditions such as dia- means of the focus group technique. This type of vali- betes, cancer, and pelvic organ prolapse, as well as in dation ensures correct understanding of questions and women at different life stages [10]. instructions by participants, as well as the identification The FSFI has been translated into several languages of words and categories used by the target population, around the world and is an internationally recognized which can help in the reformulation of items [19]. The scale [10]. In 2004, Blümel et al. [11] conducted the Span- focus group was held in July 2018, and participants were ish translation and validated the FSFI in the Chilean pop- approached through a convenience sampling method in ulation. Although the FSFI has been widely used in Spain the participating departments. [12, 13] suitable cultural validations in Spanish popula- In both sites, the chiefs of the department were first tion have only recently been published [14, 15]. approached via email in which the study was introduced While the FSFI is one of the most commonly used and the specific collaboration they were asked for was questionnaires in Spain to assess female sexual func- described. The clinical centers were requested to select tion, it has been considered too long for use in either adults women with different social and academic profiles research or routine outpatient clinics as it takes 13 min in order to ensure a greater range of inputs to our dis- for completion [16, 17]. As the use of time consuming cussion. The stakeholders signed the informed consent to tools is not usually affordable in those settings, the use participate in the focus groups, with a final sample of 10 of short versions become crucial. In fact, short versions women aged older than 18. Final group was balanced in of the original FSFI scale have been proposed, which can terms of age. be completed in 5 min or less[16, 17] and, indeed, used The focus group was carried out at the Fundació Puig- in Spain [19], which also reflects its clinical usefulness. vert meeting room and took approximately 3 h to com- However, to our knowledge, no FSFI short version has plete. Three study investigators attend the meeting been validated in the Spanish population. Thus, our aim according to the focus group methodology. was to develop and validate a Spanish short version of the At the beginning of each session, participants were FSFI. provided with an explanation of the research and were encouraged to participate and give their opinion as much Materials and methods as possible. They were handed out a copy of the ques- The development and validation of a Spanish short ver- tionnaire and were asked to give a general opinion of sion of the FSFI was conducted through a parallel explor- the comprehension of the document, as well as rephrase atory, sequential mixed-methods approach involving two complex questions in their own words. Beyond these, sites (Fundació Puigvert, Barcelona and RAPbarcelona other specific questions regarding the most controver- Clinical Centre, Barcelona). The process consisted of two sial points of the questionnaire were asked. At every par- steps: (1) cognitive and content validation, both through ticipant’s intervention, consensus was sought from all a focus group, and through item selection based on item the members of the group. This meeting was recorded response theory (IRT); (2) assessment of test–retest to allow its better transcription. Afterwards, the three reliability. investigators elaborated a final Spanish 19-item FSFI (sFSFI) version based on the analysis of the comments Cognitive and content validation of the FSFI made by patients. The FSFI comprises 19 items distributed in six domains: desire (items 1,2), arousal (items 3–6), lubrication (items Item selection by IRT analysis to elaborate the FSFI 7–10), orgasm (items 11–13), satisfaction (items 14–16), short version and pain (items 17–19). This yields a final score of 2–36, A total of 114 consecutive female patients attending the with higher scores indicating more optimal sexual outpatient clinics of the three participating departments Mateu Arrom et al. BMC Women’s Health (2021) 21:63 Page 3 of 8 were asked to complete the sFSFI. The needed num- The statistical program IBM® SPSS® v.23.0 (IBM ber of participants was calculated taking into account Corp., Armonk, NY, USA) was used for data analysis. A the formulas developed by Jiang et al. [20]. The follow- descriptive analysis of the sample and scale results was ing patients were excluded: patients under 18 years old, performed. Test–retest reliability was assessed with the patients who could not read, native Spanish speakers intraclass correlation coefficient (ICC) or kappa index for from countries other than Spain, patients with cognitive scales’ total score or item scores respectively (γ). Excel- impairment or in whom, according to the investigators’ lent reliability was considered present when γ > 0.8, good judgment, there was a risk of impaired interpretation of reliability when γ > 0.6, and moderate reliability when a scale, and patients who did not consent to enter the γ > 0.4 [24]. study. After descriptive analysis of sample demographics and Spanish FSFI short version cut off calculation scale scores, item response theory (IRT) was the main We calculated a cutoff point of sFSFI-sv in order to estab- analysis method. The IRT analyses were model-based, lish the total score of the sFSFI-sv that could indicate estimating the probability of item responses as a function presence or absence of sexual disorder. Based on clinical of the level of the underlying construct being measured interview, the same sample of patients were also classi- [21]. Analyses were conducted with IRTPRO 2.0 (Sci- fied according to the presence or absence of a sexual entific Software International, 2013). The main aim of disorder (either orgasmic, of interest/arousal or genito- the IRT analyses was to create a short form of the FSFI. pelvic pain/penetration disorder), following the Diag- The IRT analyses included: (a) fitting an appropriate nostic and Statistical Manual of Mental Disorders, fifth IRT model (the graded response model) to the ordinal- edition (DSM-V) criteria [25].We used the presence or level data capturing participant responses to each item; absence of a sexual disorder variable to calculate the total (b) calibrating the items to obtain item difficulty param- score point of the sFSFI-sv whose Area Under the Curve eters (represented by “bi” on Table 2, these parameters (AUC) based on sensibility and specificity was maximum show what level of a trait or construct provided the most on the Receiver Operating Characteristics (ROC). lower or better information in measuring), item discrimi- nation parameters (represented by “a” on Table 2, this Results parameters which items provides more discrimination Cognitive and content validation of the FSFI among participants and how accurately an item measures After an exhaustive reading of the Spanish FSFI scale, the underlying construct at its difficulty level), and item comments were collated regarding grammar, spell- information estimates [22], and (c) identifying the subset ing, and any expressions that were different from South of items that simultaneously maximized the scale’s meas- American Spanish and on this basis appropriate modi- urement and included at least one item of each domain to fications were made. Additionally, some concerns were cover the construct. raised regarding conceptual aspects of the scale, the most The result of this phase was the Spanish short version relevant being that two out of three satisfaction domain of the FSFI (sFSFI-sv). Scoring of each item was kept the items referred to a partner relationship, while satisfaction same as in the original FSFI. with sexual activity may be excellent in non-partner rela- tionships. However, the decision was taken not to imple- Test–retest reliability of the Spanish FSFI short version ment modifications relating to such concerns since they A sample of consecutive female patients attending the would have altered the meaning of the items and conse- previous outpatient clinics was collected. Exclusion cri- quently of the whole scale. teria were the same as in the previous phase. Patients were asked to complete the sFSFI-sv during the first visit Elaboration of the Spanish FSFI short version (test). After 15 days, patients reporting no relevant clini- One hundred and fourteen women were included, with a cal changes (measured by the Patient Global Impression mean age of 53.5 (14.9) years. Their demographic charac- of Improvement scale) were asked to attend a second visit teristics are shown in Table 1. to complete the sFSFI-sv again (retest). The initial IRT model using all 19 items of the FSFI The sample size was calculated using the formulas resulted in a significant S-χ2 for items 1, 2, 5, 11, 18, developed by Zou et al. [23] in concordance studies. An and 19 (all p < 0.001 with Bonferroni-corrected alpha of expected reliability was considered ρ0 = 0.850 and a mini- 0.003). The likelihood-based Goodness of Fit Statistics mum reliability was considered ρ1 = 0.750, with a statis- were Akaike information criterion (AIC) 4468.13 and tical significance of 5% and a statistical power of 80%. Bayesian information criterion (BIC) 4758.78. Considering a missing data rate of 15%, the sample size As discarding items 1 and 2 would have meant no rep- necessary was 92 patients. resentation of the desire domain, and it was the decision Mateu Arrom et al. BMC Women’s Health (2021) 21:63 Page 4 of 8 Table 1 Characteristics of patients included in the study sFSFI-sv elaboration Test–retest reliability and criterion validity All patients 114 93 Age (years), mean (SD) 53.5 (14.9) 54.9 (13.9) Education, N (%) None 2 (1.8) 2 (2.2) Elementary 21 (18.4) 18 (19.4) Secondary 34 (29.8) 26 (28) Higher 57 (50) 47 (50.5) Marital status, N (%) Single 5 (4.4) 5 (5.4) Married or steady partner 96 (84.2) 76 (81.7) Divorced 7 (6.1) 7 (7.5) Widow 5 (4.4) 5 (5.4) Children, N (%) 90 (78.9) 74 (79.6) Menopausal, N (%) 70 (61.4) 57 (61.3) Hormone replacement therapy, N (%) 5 (4.4) 4 (4.3) Reason for referral, N (%) Incontinence 46 (40.3) 39 (41.9) Pelvic organ prolapse 13 (11.4) 12 (12.9) Pelvic floor muscle dysfunction 5 (4.4) 4 (4.3) Pelvic pain 10 (8.7) 7 (7.5) Sexual dysfunction 19 (16.7) 15 (16.1) Others 21 (18.4) 16 (17.2) Comorbidities, N (%) Oncologic disease 8 (7) 7 (7.5) Neurologic disease 4(3.5) 4 (4.3) Depression 19 (16.7) 16 (17.2) Anxiety 11 (9.6) 9 (9.7) Prior pelvic surgery 35 (30.7) 29 (31.1) Frequency of sexual activity, N (%) > 4 per week 1 (0.9) 0 (0) 3–4 per week 3 (2.6) 3 (3.2) 1–2 per week 33 (28.9) 22 (23.7) 1–2 per month 42 (36.8) 36 (38.7) < once per month 35 (30.7) 32 (34.4) Continuous variables are expressed as mean (SD), while non-continuous variables are expressed as N (%). sFSFI-sv: Spanish Female Sexual Function Index – short version of the investigators to maintain all domains in the final likelihood ratio between the two models was statistically scale, the focus group comments were taken into account significant (p < 0.001). and on this basis item 1 was selected for inclusion in the Table 2 shows the difficulty and discrimination param- final scale. eter estimates and their standard error for the 14 remain- Subsequent IRT analysis was carried out using the 14 ing items of the FSFI. items selected, and a non-significant S-χ2 (all p > 0.001 On the basis of the results of the discrimination and with Bonferroni-corrected alpha of 0.003) was found for difficulty analysis, item 3 of the arousal domain, item 9 all items. The likelihood-based goodness of fit statistics of the lubrication domain, item 12 of the orgasm domain, were AIC 3264.62 and BIC 3480.02, respectively. Both and item 14 of the satisfaction domain should have been were smaller than in the initial model. Accordingly, the included in the final scale. Concordance with focus group 14-item model adjusted better. The χ2-Pearson test of the content validity assessment was observed for items 3, 9, Mateu Arrom et al. BMC Women’s Health (2021) 21:63 Page 5 of 8 Table 2 Difficulty (b) and discrimination (a) parameter estimates and their standard error for the 14 remaining items of the FSFI Domain Item a s.e b1 s.e b2 s.e b3 s.e b4 s.e b5 s.e Desire 1 1.11 0.30 − 1.70 0.54 − 0.33 0.25 1.02 0.26 3.57 1.00 Arousal 3* 5.88 1.17 − 1.10 0.25 − 0.66 0.20 − 0.28 0.13 0.27 0.11 0.79 0.18 4 4.13 1.08 − 1.04 0.19 − 0.66 0.16 − 0.13 0.11 0.59 0.14 1.42 0.22 6 4.50 1.30 − 0.84 0.14 − 0.43 0.10 − 0.21 0.09 0.25 0.09 0.79 0.18 Lubrication 7 8.03 3.27 − 0.90 0.32 − 0.27 0.12 0.00 0.06 0.28 0.10 0.76 0.26 8 5.04 1.69 − 0.90 0.27 − 0.63 0.21 − 0.22 0.08 0.22 – 0.96 0.24 9* 8.64 3.10 − 0.79 0.25 − 0.31 0.10 0.07 0.06 0.38 0.05 0.76 0.25 10 4.37 1.98 − 0.92 0.41 − 0.71 0.35 − 0.27 – 0.12 – 0.90 0.47 Orgasm 12* 3.77 0.85 − 1.02 0.20 − 0.44 0.14 − 0.20 0.10 0.17 0.14 0.99 0.14 13 3.58 0.96 − 0.86 0.19 − 0.24 0.13 − 0.08 0.12 0.12 0.14 0.79 0.14 Satisfaction 14* 2.18 0.28 − 0.68 0.14 − 0.57 0.15 − 0.43 – − 0.34 – 0.43 – 15 1.74 0.35 − 1.97 0.44 − 1.11 0.38 − 0.70 0.26 − 0.09 0.10 1.21 0.32 16 1.82 0.47 − 1.75 0.46 − 0.97 0.32 − 0.51 0.38 0.00 – 1.44 0.35 Pain 17 3.17 0.58 − 0.50 0.01 − 0.05 0.13 0.10 – 0.27 0.11 0.55 – * Items with highest discrimination and optimal difficulty indexes and 12. Regarding satisfaction, item 16 was preferred by Discussion the focus group participants, and it was the decision of In this study we conducted a cognitive validation of the the investigators to include it in the final scale in prefer- FSFI scale in a Spanish population using focus group ence to item 14. Ultimately a six-item unidimensional methodology, developed its short form through item scale was agreed as the final version (items 1, 3, 9, 12, 16, response theory (IRT) for item selection, and proceeded and 17) (Table 3). As each item was scored as in the origi- to assess its reliability in a sample of Spanish female nal FSFI from 0 or 1 to 5, the range of this short form was patients. Specific modifications of the FSFI were made from 2 to 30. according to the focus group results. Following the IRT analysis, FSFI items 1, 3, 9, 12, 16, and 17 were selected for inclusion in the final Spanish FSFI short version Test–retest reliability of the Spanish FSFI short version (sFSFI-sv), which showed good reliability. Ninety-three women were included, with a mean age All domains of the original FSFI scale were included in of 54.9 (13.9) years. All completed both the test and the scale derived through our analysis, as is also true for the retest sFSFI-sv. Their characteristics are shown in the FSFI short forms proposed by Carpenter et al. [16] Table 1. and Isidori et al. [17]. According to the initial IRT model The kappa coefficient showed moderate reliability for using all 19 items, the entire desire domain should have desire (0.72), arousal (0.69), lubrication (0.71), orgasm been excluded from the final scale. Since in DSM-V disor- (0.71), and satisfaction (0.74) and good reliability for ders of interest and arousal are included in the same diag- pain (0.80). However, the intraclass correlation coeffi- nostic category [25], mainly due to the overlap between cient showed excellent reliability for the total score of the the two phases of sexual response and ensuing symp- sFSFI-sv (0.91). toms, exclusion of the desire domain could have been justified by maintaining the arousal domain to identify patients of this diagnostic category. In fact, the authors Spanish FSFI short version cut off calculation of the original FSFI stated that a five-domain scale com- Mean results of sFSFI-sv was 19.2 (7.3). Thirty women bining interest and arousal would also have been feasible (32.3%) presented a sexual disorder based on clinical [26]. However, like the authors of the original scale [26], interview, while 63 women (67.7%) did not present a sex- we preferred to keep the six-domain structure and ulti- ual disorder. The AUC was 84.1% with a CI95% [76.2%, mately included the desire item in the final version of the 92.1%]. A total score equal or less than 18 on the sFSFI- short form. sv would indicate that the participant is at higher risk of When analyzing the items selected for the final sFSFI- sexual disorder, with a 81.0% of sensitivity and a 73.3% of sv, we realized that there was not full agreement with specificity (Fig. 1). Seventy three of the 93 participants other authors’ selections [16, 17]. Carpenter et al. [16] were classified as true positive or negative. Mateu Arrom et al. BMC Women’s Health (2021) 21:63 Page 6 of 8 Table 3 Final Spanish short version of the Female Sexual Function Index Original FSFI Spanish final translation after cognitive and content validation and scoring Item number 1 En las últimas 4 semanas, ¿Con qué frecuencia ha sentido deseo o interés sexual? (Over the past 4 weeks, how often did you feel sexual desire or interest?) Siempre o casi siempre 5 (Almost always or always) Bastantes veces 4 (Most times (more than half the time)) A veces 3 (Sometimes (about half the time)) Pocas veces 2 (A few times (less than half the time)) Casi nunca o nunca 1 (Almost never or never) 3 En las últimas 4 semanas, ¿Con qué frecuencia ha sentido excitación sexual durante la actividad sexual? (Over the past 4 weeks, how often did you feel sexually aroused ("turned on") during sexual activity or intercourse?) No he tenido actividad sexual 0 (No sexual activity) Siempre o casi siempre 5 (Almost always or always) La mayoría de las veces (más de la mitad) 4 (Most times (more than half the time)) A veces (alrededor de la mitad) 3 (Sometimes (about half the time)) Pocas veces (menos de la mitad) 2 (A few times (less than half the time)) Casi nunca o nunca 1 (Almost never or never) 9 En las últimas 4 semanas, ¿Con qué frecuencia se ha sentido lubricada (humedad vaginal) hasta el final de la actividad sexual? (Over the past 4 weeks, how often did you maintain your lubrication ("wetness") until completion of sexual activity or intercourse?) No he tenido actividad sexual 0 (No sexual activity) Siempre o casi siempre 5 (Almost always or always) La mayoría de las veces (más de la mitad) 4 (Most times (more than half the time)) A veces (alrededor de la mitad) 3 (Sometimes (about half the time)) Pocas veces (menos de la mitad) 2 (A few times (less than half the time)) Casi nunca o nunca 1 (Almost never or never) 12 En las últimas 4 semanas, cuando ha tenido estimulación sexual y/o relaciones sexuales, ¿Le ha sido difícil alcanzar el orgasmo o clímax? (Over the past 4 weeks, when you had sexual stimulation or intercourse, how difficult was it for you to reach orgasm (climax)?) No he tenido actividad sexual 0 (No sexual activity) Extremadamente difícil o imposible 1 (Extremely difficult or impossible) Muy difícil 2 (Very difficult) Difícil 3 (Difficult) Poco difícil 4 (Slightly difficult) Nada difícil (fácil) 5 (Not difficult) 16 En las últimas 4 semanas, ¿Cómo de satisfecha ha estado con su vida sexual en general? (Over the past 4 weeks, how satisfied have you been with your overall sexual life?) Muy satisfecha 5 (Very satisfied) Moderadamente satisfecha 4 (Moderately satisfied) Ni satisfecha ni insatisfecha 3 (About equally satisfied and dissatisfied) Moderadamente insatisfecha 2 (Moderately dissatisfied) Muy insatisfecha 1 (Very dissatisfied) 17 En las últimas 4 semanas, ¿Con qué frecuencia ha sentido molestia y/o dolor durante la penetración vaginal? (Over the past 4 weeks, how often did you experience discomfort or pain during vaginal penetration?) No he tenido actividad sexual 0 (Did not attempt intercourse) Siempre o casi siempre 1 (Almost always or always) La mayoría de las veces (más de la mitad) 2 (Most times (more than half the time)) A veces (alrededor de la mitad) 3 (Sometimes (about half the time)) Pocas veces (menos de la mitad) 4 (A few times (less than half the time)) Casi nunca o nunca 5 (Almost never or never) The final score is the sum of the ordinal responses to the six items; the score can range from 2 to 30 supported by their IRT analysis, tended to include items that, beyond a proper backward translation technique, related to severity and difficulty rather than frequency transcultural cognitive validation of scales is of crucial items. In contrast, in our IRT analysis, frequency items relevance in psychometric validation processes. Follow- consistently showed better discrimination and diffi- ing the same argumentation, and according to the focus culty parameters, which explained the items selected group comments, we chose item 1 and not item 2 to rep- for the arousal, lubrication, and orgasm domains. This resent the desire domain in the final sFSFI-sv. could be explained by linguistic and cultural factors, as Regarding the satisfaction domain, IRT analysis iden- within the focus group items exploring grade, intensity, tified item 14 as that with the best discrimination and or severity of the symptoms were those that generated difficulty parameters. Although items related to sexual greater confusion and discussion. This fact led us to think activity involving a partner gave rise to no difficulties Mateu Arrom et al. BMC Women’s Health (2021) 21:63 Page 7 of 8 information. However, the original FSFI questionnaire could be useful when one aims to deepen the qualitative analysis of a particular aspect of female sexual function. Our study has some limitations. First, we did not per- form backward translation. We considered the methodol- ogy described by Blümel et al. [11] as appropriate, and the resulting scale, commonly used in our setting, underwent a cognitive transcultural validation process to detect any possible misunderstandings between Chilean and Span- ish populations. Secondly, as previously stated, we can’t consider the sFSFI-sv as a diagnostic tool for sexual dys- function as it does not assess distress of these patients. To our knowledge, this is the first Spanish validation of an FSFI short version, conducted through a structured methodology. Thus, the sFSFI-sv could be used to facili- tate and spread the assessment of sexual function among Spanish women either in routine clinical practice or in a research setting. Fig. 1 Receiver Operating Characteristics (ROC) curve of the Spanish FSFI short version to establish a cut off score to detect women at higher risk of sexual disorder Conclusion After cognitive and content FSFI validation of the Span- ish FSFI, the IRT analysis and the focus group method- in terms of linguistic comprehension within the focus ology allowed the development of a six-item Spanish group, there was a general consensus among patients version of the FSFI which showed good reliability in that satisfaction with sexual activity could be high in a group of Spanish women. This scale could be used to the absence of a steady partner. Moreover, although we facilitate the assessment of female sexual function. acknowledge that marital status can be related to sex- ual satisfaction [28], including such an item in the final Abbreviations sFSFI-sv version would prevent women without a steady DSM-V: Diagnostic and Statistical Manual of Mental Disorders, fifth edition; partner from filling in the item and consequently from FSD: Female Sexual Dysfunction; FSFI: Female Sexual Function Index; ICC: completing the whole scale. Thus, item 16 was preferred Intraclass correlation coefficient; IRT: Item response theory; sFSFI-sv: Spanish Female Sexual Function Index- short version. for inclusion in the final sFSFI-sv version. No conflicts were detected between the focus group comments and Acknowledgements the IRT analysis regarding selection of the pain item, We thank Ms Esther Torres and Ms Teresa Puigpelat for their contribution in the inclusion of patients. which is in line with that selected by other authors [16, 17]. Authors’ contributions According to our results, in a range from 2 to 30, LMA conceived the study. LMA, IRG and MGF designed the study. LMA, IRG and MG, conducted the investigation. MGF designed and performed the stat‑ women with higher sFSFI-sv scores could be at lower risk ystical analysis. LMA, IRG, MGF wrote the manuscript. JPR and CES provided of suffering from sexual dysfunction, while scores equal expertise and feedback. All authors read and approved the final manuscript. or less than 18 could indicate the presence of a sexual Funding disorder. However, we have to take into account the fact No funding was obtained. that the FSFI, and consequently the sFSFI-sv, cannot be considered a diagnostic tool as it does not measure dis- Availability of data and materials The datasets used and/or analyzed during the current study are not publicly tress of these patients, which is a requirement for the available due to personal data protection policy, but are available from the diagnosis of sexual dysfunction [25]. Thus, although it corresponding author on reasonable request. seems a practical tool for screening women in clinical Ethics approval and consent to participate and for publication: practice, it cannot replace other diagnostic tools or clini- All methods were performed in accordance with the Declaration of Helsinki cal judgment. and with the institutional guidelines. Approval of the Institutional Review The main advantage of the sFSFI-sv is the less time Board was obtained (CEIm Fundació Puigvert IUNA C2018/16) and all patients gave signed informed consent to participate and for data publication before needed for its completion and interpretation, while entering any parts of the study. assessing all the female sexual function domains assessed in the original questionnaire and without losing relevant Competing interests The authors declare that they have no competing interests. Mateu Arrom et al. BMC Women’s Health (2021) 21:63 Page 8 of 8 Author details with moderate to severe vulvar lichen sclerosus. Eur J Dermatol. 1 Functional and Female Urology Department, Fundació Puigvert, C/Carta‑ 2019;29:430–1. gena 340‑350, 08025 Barcelona, Spain. 2 Department of Physioterapy, School 14. Sánchez-Sánchez B, Navarro-Brazález B, Arranz-Martín B, Sánchez-Mén‑ of Health Sciences, TecnoCampus-Pompeu Fabra University, C/Mallorca, 198 dez Ó, de la Rosa-Díaz I, Torres-Lacomba M. The Female Sexual Function 4º2ªD, 08036 Mataró, Barcelona, Spain. 3 Andrology Department, Fundació Index: Transculturally Adaptation and Psychometric Validation in Spanish Puigvert, C/Cartagena 340‑350, 08025 Barcelona, Spain. 4 Urology Department, Women. Int J Environ Res Public Health. 2020;17:994. Fundació Puigvert, C/Cartagena 340‑350, 08025 Barcelona, Spain. 5 Functional 15. Pérez-Herrezuelo I, Hita-Contreras F, Martínez-Amat A, Aibar-Almazán and Female Urology department, Fundació Puigvert, C/Cartagena 340‑350, A, Cruz-Díaz D, Wangensteen R, et al. The female sexual function index: 08025 Barcelona, Spain. 6 Department of Physioterapy, Faculty of Health reliability and validity in Spanish postmenopausal women. Menopause. Sciences, Blanquerna - Ramon Llull University, C/Padilla 326, 08025 Barcleona, 2019;26:401–8. Spain. 16. Carpenter JS, Jones SM, Studts CR, Heiman JR, Reed SD, Newton KM, et al. Female Sexual Function Index Short Version: A MsFLASH Item Response Received: 27 October 2020 Accepted: 3 February 2021 Analysis. Arch Sex Behav. 2016;45:1897–905. 17. Isidori AM, Pozza C, Esposito K, Giugliano D, Morano S, Vignozzi L, et al. Development and validation of a 6-item version of the female sexual function index (FSFI) as a diagnostic tool for female sexual dysfunction. J Sex Med. 2010;7:1139–46. References 18. Pérez-López FR, Fernández-Alonso AM, Trabalón-Pastor M, Vara 1. Ojaniatva A, Makinen J, Helenius H, Korkeila D, Sundell J, Rautava P. Sexual C, Chedraui P. MenopAuse RIsk Assessment (MARIA) Research Group. activity and perceived health among Finnish middle-aged women. Assessment of sexual function and related factors in mid-aged sexu‑ Health Qual Life Outcomes. 2006;4:29. ally active Spanish womenwith the six-item Female Sex Function Index. 2. Graziottin A, Leiblum SR. Biological and psychosocial pathophysiology of Menopause. 2012;19:1224–30. female sexual dysfunction during the menopausal transition. J Sex Med. 19. Morales P. Medición de actitudes en psicología y educación. Construc‑ 2005;2:133–45. ción de escalas y problemas metodológicos. Madrid: Universidad Pontifi‑ 3. Jones LR. The use of validated questionnaires to assess female sexual cia de Comillas; 2000. dysfunction. World J Urol. 2002;20:89–92. 20. Jiang S, Wang C, Weiss DJ. Sample size requirements for estimation of 4. Filocamo MT, Serati M, Li Marzi V, Costantini E, Milanesi M, Pietropaolo A, item parameters in the multidimensional graded response model. Front et al. The Female Sexual Function Index (FSFI): linguistic validation of the Psychol. 2016;7:109. Italian version. J Sex Med. 2014;11:447–53. 21. Hambleton RK, Swaminathan H. Item response theory: Principles and 5. Thakar R. Review of current status of female sexual dysfunction evalua‑ applications. Norwell, MA: Kluwer Academic; 1985. tion in urogynecology. Int Urogynecol J. 2009;1:S27-31. 22. Hays RD, Morales LS, Reise SP. Item response theory and health outcomes 6. Lowenstein L, Pierce K, Pauls R.Urogynecology and sexual function measurement in the 21st century. Medical Care, 2000;38:II28–42. research. How are we doing? J Sex Med. 2009;6:199–204. 23. Zou G. Sample size formulas for estimating intraclass correlation coef‑ 7. Rosen R, Brown C, Heiman J, Leiblum S, Meston C, Shabsigh R, et al. The ficients with precision and assurance. Stat Med. 2012;31:3972–81. Female Sexual Function Index (FSFI): A multidimensional self-report 24. Fleiss JL, Levin B, Paik MC. Statistical methods for rates and proportions. instrument for the assessment of female sexual function. J Sex Marital 3rd ed. New York: Wiley; 2004. Ther. 2000;26:191–208. 25. American Psychiatric Association. Diagnostic and Statistical Manual of 8. Wiegel M, Meston C, Rosen R. The female sexual function index (FSFI): Mental Disorders. 2013. 5th ed. Washington, DC: American Psychiatric cross-validation and development of clinical cutoff scores. J Sex Marital Publishing. Ther. 2005;31:1–20. 26. Meston CM, Freihart BK, Handy AB, Kilimnik CD, Rosen RC. Scoring and 9. Meston CM, Derogatis LR. Validated instruments for assessing female Interpretation of the FSFI: What can be Learned From 20 Years of use? J sexual function. J Sex Marital Ther. 2002;28:155–64. Sex Med. 2020;17:17–25. 10. Takahashi M, Inokuchi T, Watanabe C, Saito T, Kai I. The Female Sexual 27. Pascoal PM, Byers ES, Alvarez MJ, Santos-Iglesias P, Nobre PJ, Pereira CR, Function Index (FSFI): Development of a Japanese version. J Sex Med. Laan E. A dyadic approach to understanding the link between sexual 2011;8:2246–54. functioning and sexual satisfaction in heterosexual couples. J Sex Res. 11. Blümel JE, Binfa L, Cataldo P, Carrasco V, Humberto L, Salvador C. Índice 2018;55:1155–66. de funcion sexual femenina: un test para evaluar la sexualidad de la mujer. Rev Chil Obstet Ginecol. 2004;69:118–25. 12. Soto Campos JG, Rojas Villegas J, Padilla Galo A, Marina Malanda N, Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in pub‑ Garcia Rivero JL, Pinedo Sierra C, et al. Impact of asthma on the sexual lished maps and institutional affiliations. functioning of patients. A case-control study. Arch Bronconeumol. 2017;53:667–74. 13. Gutierrez-Ontalvilla P, Botella R, Iborra M, Giner F, Negueroles D, Cortell J, Vicente D. The Female Sexual Function Index to assess patients Ready to submit your research ? 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