Instrumentos de medida para a área de saúde da mulher: significância clínica de questionários e diagnóstico de acurácia da função dos músculos do assoalho pélvico

Abstract

Introduction: Although there are previous studies looking at different proprieties (i.e., reliability, validity, internal consistency, and others) of outcome measures for several conditions, few researchers are dedicated to developing and refining the methodology to understand the clinical significance or the diagnostic accuracy of outcomes related to urinary incontinence (UI) and pelvic floor muscles (PFM) function, respectively. In the era of Evidence-Based Practice (EBP) is crucial that research supports clinical practice and clinical significance of relevant outcome measures is evaluated. Objective: To increase the evidence regarding measurements proprieties that can be used in the women’s health field. Materials and Methods: This project was conducted in two steps: the first study (Article 1) was a systematic review that synthetized all Minimal Important Differences (MIDs) of outcomes related to UI in the literature, and the second study (Article 2) was a cross-sectional study that analyzed which variables from the PeritronTM manometer could differentiate women with/without a weak/strong PFM contraction and determine their cut-off points for this discrimination. Article 1 was conducted as the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. Five online databases were consulted (Medline, Embase, CINAHL, Web of Science, and Scopus) in order to find patient-reported outcome measures (PROMs) related to female UI outcomes. The credibility and certainty of the evidence were assessed for MIDs reported by anchor-based methods. Absolute MIDs (mean difference associated with minimal improvement) were calculated for each study separately according to the mean change of the group of participants by checking the original papers and by extracting the mean change of the group of participants that reported a slight improvement, according to the anchor applied during data collection, when possible. The quality of the evidence was assessed by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Article 2 included one hundred and fifty-six women (mean age 40±16.0 SD years) were included. The reference test was vaginal palpation and vaginal manometry (PeritronTM manometer) was the index test. Variables were rest, maximal voluntary contraction (CVM), intravaginal pressure average, duration, gradient, area under the curve (AUC), and contraction speed. The Receiver Operating Curve (ROC) and logistic regression were used to analyze the data data to determine the variables which better discriminated between women with/without a weak/strong PFM contraction and obtain their cut-off points. Results: For the Article 1, 11 studies were included and twelve PROMs were found with their respective MIDs (48 and 65 MIDs reported according to distribution-based and anchor-based methods, respectively). MIDs according to distribution- methods were reported by the effect size (range from -49.7 to 12.1 points), standard error of the measurement (SEM) (range -18.2 to 4.3) and standardized response mean (range from 1.3 to 1.4). MIDs for anchor-based methods reported by studies varied from -44.6 to 6.9 points. Most of the included studies did not consider the smallest difference identified by the participants to calculate the MIDs. Eleven absolute MIDs on the range of 0-10 (range from 2 to 7 points) and 10 absolute MIDs from -150 to +150 were calculated (range from -51 to 47 points). All reports related to MID according to anchor-based methods presented low credibility and very low certainty of the evidence. In Article 2, an excellent ability to discriminate women with a weak/strong PFM contraction was found for intravaginal pressure average (cut-off: 28.93 cmH2O), MVC (cut-off: 38.61 cmH2O), and the AUC (cut-off: 1011.93 cmH2O). The gradient variable had good discrimination ability (AUC=0.81; cut-off: 28.68 cmH2O). The intravaginal pressure average assessed by manometry, menopausal status, and stress urinary incontinence (SUI) were associated with PFM contraction in the multivariate analysis; however, the most parsimonious model to discriminate weak/strong PFM contraction included only the intravaginal pressure average (AUC = 0.95; sensitivity: 0.87; specificity: 0.91). Conclusion: There is a high variability of MIDs related to PROMs for UI outcomes according to the method of analysis, PROMs and anchors used, however, the credibility and certainty of the evidence to support these MIDs is still limited. Results should be interpreted with caution and future studies must be conduct following previous recommendations about how to calculate and analyze MID. In addition, the best variables to discriminate women with a weak/strong PFM contraction using a vaginal manometer were intravaginal pressure average, peak of MVC, AUC, and gradient. The best model to discriminate weak/strong PFM contraction included only the intravaginal pressure average. These variables could be used in clinical and research practice to assess PFM contraction.