Background
Method
Subjects and procedure
Measures
Psychometric validation
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Reliability: This was evaluated in two ways:
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Construct Validity: This was evaluated through:
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Discriminant Construct Validity: This aspect of the study focused on evaluating the scale’s capacity to distinguish between different participant groups based on anticipated variations in scores. The key clinical variable used for this differentiation was the degree of disability, which was assessed using the EDSS with a threshold value set at 3.0. To compare scores between groups, the Wilcoxon-Mann-Whitney test was employed.
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Interpretability and Feasibility: Although not psychometric measures, these characteristics were still considered [28]. Interpretability was assessed using the percentage of unanswered individual items and the ceiling-floor effect. Feasibility was assessed by calculating the average completion time [17].
Assessment of prevalence and association with demographic and clinical variables
Patient and public involvement
Results
Participants
Age (years), X (SD) | 38.3 (7.2) |
Disease duration (years), X (SD) | 8.3 (6.0) |
History of childbirth, n (%) | 52 (49.1) |
Stable partner, n (%) | 91 (75.2) |
Professional status: active, n (%) | 94 (75.2) |
EDSS (median, p25 – p75) | 2 (1–2.5) |
- EDSS < 3, n (%) | 115 (83.9) |
- EDSS ≥3, n (%) | 22 (16.1) |
Patients on DMT | |
- No treatment | 20 (14.6) |
- First line, n (%) | 38 (27.7) |
- heDMT, n (%) | 79 (57.7) |
Myelitis, n (%) | 85 (62.5) |
- Cervical, n (%) | 41 (53.9) |
- Dorsal, n (%) | 9 (11.8) |
- > 1 level, n (%) | 26 (34.2) |
- Diffuse, n (%) | 0 |
Sphincter symptoms, n (%) | 53 (38.7) |
Referred fatigue, n (%) | 51 (37.8) |
MFIS (n = 58), X (SD) | 20.4 (18.3) |
Depression on specific treatment | 18 (13.2) |
BDI-II (n = 54), X (SD) | 23.5 (19.6) |
Women on CNS depressants, n (%) | 32 (23.5) |
Psychometric validation
Reliability
Domain | Cronbach’s Alpha |
---|---|
Desire | 0.885 |
Arousal | 0.947 |
Lubrication | 0.965 |
Orgasm | 0.943 |
Satisfaction | 0.905 |
Pain | 0.958 |
Total FSFI | 0.977 |
Test, mean (SD) | Retest, mean (SD) | SEMagreement | SDCind | SDCgroup | ICC (95%CI) | |
---|---|---|---|---|---|---|
Desire | 3.4 (1.3) | 3.5 (1.3) | 0.51 | 1.41 | 0.31 | 0.845 (0.66–0.93) |
Arousal | 4.3 (1.5) | 4.3 (1.5) | 0.47 | 1.31 | 0.29 | 0.901 (0.77–0.96) |
Lubrication | 4.5 (1.5) | 4.6 (1.5) | 0.34 | 0.94 | 0.21 | 0.948 (0.88–0.98) |
Orgasm | 4.9 (1.4) | 4.8 (1.4) | 0.44 | 1.22 | 0.26 | 0.9 (0.77–0.96) |
Satisfaction | 4.9 (1.1) | 4.9 (1.2) | 0.30 | 0.86 | 0.19 | 0.928 (0.83–0.97) |
Pain | 5.2 (1.5) | 5.0 (1.5) | 0.34 | 0.95 | 0.21 | 0.948 (0.87–0.98) |
Total FSFI | 27.3 (7.3) | 27.2 (7.3) | 1.44 | 3.99 | 0.87 | 0.96 (0.91–0.98) |
Validity
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Convergent construct validity indicated strong correlations within all domains and with the total FSFI score. The domains with the highest intercorrelations were arousal with lubrication, satisfaction, orgasm, and pain; lubrication with orgasm and pain; and orgasm with pain (Table 5).
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In terms of discriminant construct validity, women with an EDSS score < 3 reported significantly higher FSFI scores (26.2) compared to those with an EDSS score ≥ 3 (8.7), with no differences observed in the domain. These differences might be influenced by factors such as longer disease duration and higher age in the latter group (Table 6).
Items | Domain: item | F1 | F2 | F3 | F4 | F5 |
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Item 1 | Desire: frequency | 0.15 | 0.10 | 0.80 | 0.18 | 0.15 |
Item 2 | Desire: level | 0.16 | 0.17 | 0.85 | 0.20 | 0.07 |
Item 3 | Arousal: frequency | 0.37 | 0.42 | 0.56 | 0.25 | 0.28 |
Item 4 | Arousal: level | 0.47 | 0.31 | 0.57 | 0.30 | 0.31 |
Item 5 | Arousal: confidence | 0.56 | 0.38 | 0.48 | 0.22 | 0.34 |
Item 6 | Arousal: satisfaction | 0.53 | 0.35 | 0.37 | 0.29 | 0.49 |
Item 7 | Lubrication: frequency | 0.73 | 0.33 | 0.34 | 0.28 | 0.27 |
Item 8 | Lubrication: difficulty | 0.74 | 0.39 | 0.17 | 0.26 | 0.29 |
Item 9 | Lubrication: frequency of maintaining | 0.73 | 0.35 | 0.26 | 0.28 | 0.31 |
Item 10 | Lubrication: difficulty in maintaining | 0.63 | 0.46 | 0.24 | 0.21 | 0.38 |
Item 11 | Orgasm: frequency | 0.43 | 0.31 | 0.25 | 0.25 | 0.69 |
Item 12 | Orgasm: difficulty | 0.42 | 0.40 | 0.23 | 0.28 | 0.67 |
Item 13 | Orgasm: satisfaction | 0.41 | 0.39 | 0.17 | 0.36 | 0.55 |
Item 14 | Satisfaction: with closeness with partner | 0.45 | 0.41 | 0.28 | 0.52 | 0.32 |
Item 15 | Satisfaction: with sexual relationship | 0.24 | 0.23 | 0.26 | 0.86 | 0.19 |
Item 16 | Satisfaction: with overall sex life | 0.24 | 0.23 | 0.31 | 0.72 | 0.21 |
Item 17 | Pain: frequency during vaginal penetration | 0.35 | 0.73 | 0.23 | 0.23 | 0.21 |
Item 18 | Pain: frequency following vaginal penetration | 0.32 | 0.83 | 0.21 | 0.25 | 0.27 |
Item 19 | Pain: level during or following vaginal penetration | 0.38 | 0.75 | 0.23 | 0.27 | 0.28 |
Eigenvalue | 14.55 | 2.38 | 1.84 | 1.65 | 1.37 | |
% of explained variance | 22 | 19 | 17 | 14 | 13 |
TOTAL | Desire/arousal | Lubrication/arousal | Orgasm | Satisfaction | Pain | Global |
---|---|---|---|---|---|---|
Desire/arousal | 1 | |||||
Lubrication/arousal | 0.785a | 1 | ||||
Orgasm | 0.699a | 0.876a | 1 | |||
Satisfaction | 0.720a | 0.775a | 0.763 a | 1 | ||
Pain | 0.683a | 0.820a | 0.779 a | 0.715a | 1 | |
Total FSFI | 0.868a | 0.955a | 0.915 a | 0.869 a | 0.884 a | 1 |
EDSS < 3 (n = 104) | EDSS > 3 (n = 21) | p–value | |||||||
---|---|---|---|---|---|---|---|---|---|
Mean | SD | Median | p25 – p75 | Mean | SD | Median | p25 – p75 | ||
Desire | 3.5 | 1.2 | 3.6 | 2.4–4.2 | 3.1 | 1.3 | 2.7 | 2.4–4.65 | 0.183 |
Arousal | 4.2 | 1.7 | 4.8 | 3.3–5.4 | 3.1 | 1.7 | 3.6 | 2.2–4.4 | 0.001 |
Lubrication | 4.5 | 1.9 | 5.1 | 4.1–6 | 3.5 | 2.2 | 4.2 | 2.8–5.3 | 0.008 |
Orgasm | 4.3 | 1.9 | 5.2 | 3.6–5.6 | 3.2 | 2.1 | 3.6 | 2–5.1 | 0.004 |
Satisfaction | 4.6 | 1.6 | 4.8 | 4–6 | 3.6 | 1.6 | 3.8 | 2.4–4.8 | 0.002 |
Pain | 4.9 | 1.8 | 6.0 | 4.8–6 | 3.8 | 2.1 | 4.2 | 3.3–5.8 | 0.004 |
Total FSFI | 26.2 | 8.7 | 28.9 | 23.6–32.3 | 20.3 | 9.9 | 24.1 | 15.7–26.9 | 0.002 |
Interpretability
svFSFI score assessment in women with MS: prevalence and influencing variables for SD
Domains | X | SD | Median | p25 – p75 |
---|---|---|---|---|
Desire (1.2–6.0) | 3.5 | 1.2 | 3.6 | 2.4–4.2 |
Arousal (0–6.0) | 4.1 | 1.7 | 4.5 | 3.3–5.4 |
Lubrication (0–6.0) | 4.4 | 2.0 | 5.1 | 3.6–6.0 |
Orgasm (0–6.0) | 4.1 | 2.0 | 4.8 | 3.2–5.6 |
Satisfaction (0.8–6.0) | 4.5 | 1.6 | 4.8 | 3.6–6.0 |
Pain (0–6.0) | 4.8 | 1.9 | 5.6 | 4.4–6.0 |
Total FSFI (2.0–36) | 25.3 | 9.1 | 28 | 22.4–31.9 |
Variable | Spearman Rho | P- value | Adjusted P- value * |
---|---|---|---|
Baseline EDSS | - 0.303 | 0.000 | 0.002* |
Baseline age | - 0.124 | 0.148 | 0.222 |
Baseline disease duration | - 0.037 | 0.666 | 0.666 |
Childbirths | 0.092 | 0.448 | 0.538 |
MFIS | - 0.316 | 0.015 | 0.032* |
BDI-II | - 0.323 | 0.016 | 0.032* |