Determining minimal clinically important differences in the Hammersmith Functional Motor Scale Expanded for untreated spinal muscular atrophy patients: An international study

BACKGROUND AND PURPOSE

Spinal muscular atrophy (SMA) is a rare and progressive neuromuscular disorder with varying severity levels. The aim of the study was to calculate minimal clinically important difference (MCID), minimal detectable change (MDC), and values for the Hammersmith Functional Motor Scale Expanded (HFMSE) in an untreated international SMA cohort.

METHODS

The study employed two distinct methods. MDC was calculated using distribution-based approaches to consider standard error of measurement and effect size change in a population of 321 patients (176 SMA II and 145 SMA III), allowing for stratification based on age and function. MCID was assessed using anchor-based methods (receiver operating characteristic [ROC] curve analysis and standard error) on 76 patients (52 SMA II and 24 SMA III) for whom the 12-month HFMSE could be anchored to a caregiver-reported clinical perception questionnaire.

RESULTS

With both approaches, SMA type II and type III patients had different profiles. The MCID, using ROC analysis, identified optimal cutoff points of -2 for type II and -4 for type III patients, whereas using the standard error we found the optimal cutoff points to be 1.5 for improvement and -3.2 for deterioration. Furthermore, distribution-based methods uncovered varying values across age and functional status subgroups within each SMA type.

CONCLUSIONS

These results emphasize that the interpretation of a single MCID or MDC value obtained in large cohorts with different functional status needs to be made with caution, especially when these may be used to assess possible responses to new therapies.

Functional and radiographic results of anatomic total shoulder arthroplasty in the setting of subscapularis dysfunction: 5-year outcomes analysis

BACKGROUND

Subscapularis management is a critical component to the success of anatomic total shoulder arthroplasty (TSA). Failure to heal the subscapularis can result in pain, weakness, loss of function, and revision. However, not all patients have poor outcomes. The purpose of this study is to compare patients with normal and dysfunctional subscapularis function following TSA in regard to (1) patient-reported outcome measures (PROMs); (2) range of motion (ROM) and strength; (3) achievement of minimal clinically important differences (MCIDs); and (4) specific functional internal rotation tasks.

METHODS

A retrospective review of patients treated with TSA for osteoarthritis with a minimum 2-year follow-up was performed to identify patients with subscapularis dysfunction. Subscapularis dysfunction was diagnosed when any degree of weakness in internal rotation was detected on physical examination (positive belly press sign). These patients were case controlled matched on a 1:3 ratio to patients with normal subscapularis function based on age and sex. PROMs, measured active motion, revision rates, patient satisfaction, and postoperative radiographic findings were compared. Population-specific institutional anchor-based MCID values were used to compare the improvement in PROM.

RESULTS

Of the 668 patients included, 34 patients (5.1%) demonstrated evidence of subscapularis dysfunction. Mean follow-up for the normal subscapularis function cohort was 63.4 ± 29.7 and 58.7 ± 26.8 for the dysfunctional subscapularis cohort. Patients with subscapularis dysfunction demonstrated significantly worse postoperative Simple Shoulder Test, Single Assessment Numerical Evaluation, visual analog scale (VAS) function, VAS pain, and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores with higher rates of unsatisfactory results when compared to patients with normal subscapularis function. Abduction, elevation, internal rotation ROM, along with supraspinatus and external rotation strength were also significantly worse in the dysfunctional group. Similarly, these patients were more likely to have decreased ability to perform functional internal rotation tasks, with only 47% of the patients being able to reach the small of their back compared to 85% with normal subscapularis function. Radiographically, the dysfunctional cohort demonstrated higher rates of anterior subluxation (56% vs. 7%; P < .001) and glenoid loosening (24% vs. 5%; P = .004). Similarly, revision rates were significantly higher for patients with subscapularis dysfunction (8 patients, 23.5%). Nonetheless, the dysfunctional subscapularis cohort demonstrated improvements in VAS pain (4.0 ± 3.7) and ASES (46.4 ± 35.9) scores that exceeded MCID thresholds.

CONCLUSION

Patients who develop subscapularis dysfunction after TSA have significantly worse PROMs, ROM, functional tasks of internal rotation, and radiographic outcomes, as well as increased rates of revision. Although patients show worse outcomes and high revision rates compared with their normal-functioning counterparts, these patients maintained improvement above MCID thresholds for pain and function at a mean 5-year follow-up.

Minimal Clinically Important Differences and Changes in Stroke Disease-Specific Quality of Life in Stroke Survivors: A Prospective Cohort Study

The aims of the present study were to investigate changes in QOL in post-stroke patients during the first 3 months of rehabilitation treatment. We estimate minimal detectable changes (MDCs) and minimal clinically important differences (MCIDs) of the eight dimensions of QOL and assess the proportion of patients' change scores that exceed MDCs and MCIDs in stroke survivors who receive rehabilitation in a hospital ward. This prospective cohort study enrolled 40 stroke survivors (57.5% male; M_age = 58.3 years) who received in-hospital rehabilitation for a total of 3 months. The Stroke Impact Scale 3.0, which has eight subscales-strength, activities of daily living (ADLs)/instrumental ADLs (IADLs), mobility, hand function, communication, memory and thinking, emotion, and social participation-was used for assessment on the third day of rehabilitation (Time 1), 1 month later (Time 2), and 3 months later (Time 3). Our findings indicated that the MDC₉₅ and MCID proportions varied from 7.5% to 30% and 7.5% to 65%, respectively, of individuals who exhibited change based on individual change scores. The findings show compliance with MDC and MCID values in physical function, with the lowest proportion in hand function.

Healthcare Professionals' Preferred Efficacy Endpoints and Minimal Clinically Important Differences in the Assessment of New Medicines for Chronic Obstructive Pulmonary Disease

BACKGROUND

Registration authorities evaluate effects of new medicines for chronic obstructive pulmonary disease (COPD) on airway obstruction, dyspnea, health status and exacerbations. To establish clinical relevance, minimal clinically important differences (MCIDs) are used. The aim of this study was to investigate which efficacy endpoints and MCIDs healthcare professionals consider clinically relevant for new COPD medicines.

MATERIALS AND METHODS

7,731 Healthcare professionals received an electronic questionnaire. Participants were asked for: 1) preferred efficacy endpoints for new COPD medicines and 2) cut-off values defining clinical relevance for forced expiratory volume in 1 sec (FEV1), Transition Dyspnea Index (TDI) and St. George's Respiratory Questionnaire (SGRQ). Those cut-off values were compared to the MCIDs used by registration authorities, namely 100 ml for FEV1, 1 unit for TDI and 4 units for SGRQ.

RESULTS

227 Healthcare professionals responded to the questionnaire. Most preferred efficacy endpoints were exacerbations (51.0%), airway obstruction (46.9%) and health status (44.9%). Mean cut-off values for TDI and SGRQ were significantly higher than the corresponding MCIDs, mean differences 1.5 (95%CI = 1.3-1.8, p < 0.001) and 7.0 (95%CI = 5.1-8.8, p < 0.001), respectively. The mean cut-off value for FEV1 was comparable to the MCID (mean difference 2.2, 95%CI = -19.9-24.3, p = 0.84).

CONCLUSIONS

Healthcare professionals largely agree with efficacy endpoints used for the evaluation of new COPD medicines. However, they seem to prefer higher cut-off values for clinical relevance for TDI and SGRQ than the registration authorities. Effects of new medicines on TDI and SGRQ that are considered clinically relevant by registration authorities do, therefore, not necessarily reflect healthcare professionals' perspectives on clinical relevance.

Reliability and minimal clinically important differences of forced vital capacity: Results from the Scleroderma Lung Studies (SLS-I and SLS-II)

OBJECTIVES

To assess the reliability and the minimal clinically important differences (MCID) for FVC% predicted in the Scleroderma Lung Study I and II.

METHODS

Using data from SLS I and II (N=300), we evaluated the test-retest reliability for FVC% predicted (FVC%; screening vs. baseline) using intra-class correlation (ICC). MCID estimates at 12 months were calculated in the pooled cohort (SLS-I and II) using 2 anchors: Transition Dyspnea Index (≥change of 1.5 units for improvement and worsening, respectively) and the SF-36 Health Transition question: "Compared to one year ago, how would you rate your health in general now?", where "somewhat better" or "somewhat worse" were defined as the MCID estimates. We next assessed the association of MCID estimates for improvement and worsening of FVC% with patient reported outcomes (PROs) and computer-assisted quantitation of extent of fibrosis (QLF) and of total ILD (QILD) on HRCT.

RESULTS

Reliability of FVC%, assessed at a mean of 34 days, was 0.93 for the pooled cohort. The MCID estimates for the pooled cohort at 12 months for FVC% improvement ranged from 3.0 % to 5.3% and for worsening from -3.0% to -3.3%. FVC% improvement by ≥MCID was associated with either statistically significant or numerical improvements in some PROs, QILD, and QLF, while FVC% worsening ≥MCID was associated with statistically significant or numerical worsening of PROs, QILD, and QLF.

CONCLUSION

FVC% has acceptable test-retest reliability, and we have provided the MCID estimates for FVC% in SSc-ILD based changes at 12 months from baseline in two clinical trials. Clinical trial registration available at www.clinicaltrials.gov, IDs NCT00004563 and NCT00883129.