The minimal important difference of patient-reported outcome measures related to female urinary incontinence: a systematic review.

BACKGROUND: The minimal important difference is a valuable metric in ascertaining the clinical relevance of a treatment, offering valuable guidance in patient management. There is a lack of available evidence concerning this metric in the context of outcomes related to female urinary incontinence, which might negatively impact clinical decision-making. OBJECTIVES: To summarize the minimal important difference of patient-reported outcome measures associated with urinary incontinence, calculated according to both distribution- and anchor-based methods. METHODS: This is a systematic review conducted according to the PRISMA guidelines. The search strategy including the main terms for urinary incontinence and minimal important difference were used in five different databases (Medline, Embase, CINAHL, Web of Science, and Scopus) in 09 June 2021 and were updated in January 09, 2024 with no limits for date, language or publication status. Studies that provided minimal important difference (distribution- or anchor-based methods) for patient-reported outcome measures related to female urinary incontinence outcomes were included. The study selection and data extraction were performed independently by two different researchers. Only studies that reported the minimal important difference according to anchor-based methods were assessed by credibility and certainty of the evidence. When possible, absolute minimal important differences were calculated for each study separately according to the mean change of the group of participants that slightly improved. RESULTS: Twelve studies were included. Thirteen questionnaires with their respective minimal important differences reported according to distribution (effect size, standard error of measurement, standardized response mean) and anchor-based methods were found. Most of the measures for anchor methods did not consider the smallest difference identified by the participants to calculate the minimal important difference. All reports related to anchor-based methods presented low credibility and very low certainty of the evidence. We pooled 20 different estimates of minimal important differences using data from primary studies, considering different anchors and questionnaires. CONCLUSIONS: There is a high variability around the minimal important difference related to patient-reported outcome measures for urinary incontinence outcomes according to the method of analysis, questionnaires, and anchors used, however, the credibility and certainty of the evidence to support these is still limited.

Isokinetic testing of quadriceps function in COPD: feasibility, responsiveness, and minimal important differences in patients undergoing pulmonary rehabilitation.

BACKGROUND: Isokinetic testing of peripheral muscle function is valid and reliable in patients with chronic obstructive pulmonary disease (COPD). OBJECTIVE: To evaluate whether and to what extent isokinetic testing of quadriceps function meets pre-defined test criteria in patients with COPD; to determine the response to pulmonary rehabilitation (PR), and to calculate minimal important differences (MIDs) of isokinetic quadriceps function. METHODS: Retrospective analysis of 2033 patients with COPD (age: 65±9 years, body mass index: 26±6 kg/m2, FEV1: 49±22% predicted) who followed a comprehensive PR program. Pre and post PR isokinetic quadriceps function was assessed with 30 maximal extension-flexion contractions at an angular speed of 90°/s on a computerized dynamometer. The chosen anchors were 6-min walk test and COPD assessment test. RESULTS: Pre PR, 27% of the patients performed the isokinetic test incorrectly. In male and female patients with a correct pre and post PR isokinetic test, peak torque (Δ=10±13 Nm or 9% and Δ=7±9 Nm or 10%, respectively) and total work (Δ=263±270 J or 14% and Δ=198±190 J or 15%, respectively) improved significantly. There was no change in work fatigue index following PR. Using distribution-based calculations, MID estimates for peak torque and total work ranged between 6-7 Nm and 97-135 J in males and between 4-5 Nm and 62-99 J in females. CONCLUSIONS: Based on the current test criteria, three in four patients with COPD performed the isokinetic quadriceps test correctly during baseline PR assessment. Furthermore, peak torque and total work, but not work fatigue index, were responsive to PR and sex-specific MIDs were established.