Addressing Bias in Responder Analysis of Patient-Reported Outcomes

Meaningful Symptomatic Change in Patients With Myelofibrosis From the SIMPLIFY Studies

OBJECTIVES

Patients with myelofibrosis develop symptoms due to bone marrow fibrosis, systemic inflammation, and/or organomegaly. Alleviating symptoms improves overall quality of life. Clinical trials have historically defined symptom response as a reduction of at least 50% in Total Symptom Score at week 24 compared with baseline. Whether 50% constitutes a meaningful benefit has not been established. This study determined the meaningful change threshold (MCT) for 2 momelotinib phase III trials, SIMPLIFY-1 and SIMPLIFY-2.

METHODS

The absolute and percentage MCT was determined using anchor-based methods applied to the modified Myeloproliferative Neoplasm Symptom Assessment Form v2.0 and Patient Global Impression of Change. MCTs were applied retrospectively to determine responder rates. Generalized estimating equations estimated the treatment-related difference in likelihood of improvement.

RESULTS

In SIMPLIFY-1, a Janus kinase inhibitor-naive population, the MCT was 8 points. In SIMPLIFY-2, a previously Janus kinase inhibitor-treated population, the MCT was 6 points. A 32% MCT was determined in both studies, showing that the historic 50% reduction threshold may be a conservative choice. In SIMPLIFY-1, a similar proportion of patients achieved responder status with 24 weeks of momelotinib or ruxolitinib therapy based on the absolute MCT (39% vs 41%, respectively). In SIMPLIFY-2, a significantly greater proportion of patients treated with momelotinib achieved responder states compared with best available therapy based on absolute and percent change MCTs.

CONCLUSIONS

This study demonstrates that momelotinib provided clinically meaningful symptom benefit for patients with myelofibrosis and provides insight into the appropriateness of the symptom change threshold used in historical studies.

Which patients with chronic low back pain respond favorably to multidisciplinary rehabilitation? A secondary analysis of a randomized controlled trial

OBJECTIVES

The aim of this study was to identify prognostic variables at baseline associated with being responding favorably to multidisciplinary rehabilitation in patients with chronic low back pain (CLBP).

METHODS

A responder analysis was conducted based on data from a randomized controlled trial with 26-week follow-up including 165 patients with CLBP treated at a Danish multidisciplinary rehabilitation center. Patients were dichotomized into responders and non-responders based on the outcome of a minimal clinically important difference of six points on the Oswestry Disability Index. The associations between prognostic variables and responders were analyzed using logistic regression.

RESULTS

A total of 139 patients completed the study, of which 42% were classified as responders. Sex and employment status were statistically significant, with a decreased odds ratio (OR) of being a responder found for males compared to females (OR = 0.09, 95% CI = 0.02-0.48) and for being on temporary or permanent social benefits (OR = 0.28, 95% CI = 0.10-0.75) compared to being self-supporting or receiving retirement benefits. Statistically significant interaction (OR = 8.84, 95% CI = 1.11-70.12) was found between males and being on temporary or permanent social benefits.

CONCLUSIONS

In patients with CLBP, female patients as well as patients who were self-supporting or receiving retirement benefits were significantly more likely than male patients or patients on temporary or permanent social benefits to be a responder to multidisciplinary rehabilitation.

Family functioning and delinquency among Chinese adolescents: Mediating effects of positive behavior recognition according to the humanistic perspective

Background

Empirical research on the relationship between family functioning and delinquency has been sparse, although many studies have focused on the influence of family functioning on adolescent development. The current research aimed to fill this gap by exploring the influences of family functioning on adolescent delinquency and the mechanisms connecting the processes.

Methods

We derived the baseline data from a prospective observational school-based cohort Chengdu Positive Child Development (CPCD) project. Students responded to a questionnaire containing validated measures of family functioning, positive behavior recognition, and delinquent behavior. We utilized structural equation modeling and maximum likelihood estimation to test the relationships.

Results

Across 8811 Chinese adolescents, the incidence of delinquency behaviors among Chinese adolescents was relatively low. Family functioning and positive behavior recognition negatively predict delinquency (p < 0.001). Further, positive behavior recognition partially mediated the influence of family functioning on delinquency [p < 0.001, std. error = 0.01, 95% CI = (0.04, 0.07)]. Adolescents with better family functioning had little delinquency behavior, with positive behavior recognition and delinquency behavior negatively reinforcing each other.

Conclusions

This study demonstrated that family functioning was a protective factor against adolescent delinquency and revealed that positive behavior recognition was a critical mediating mechanism linking family functioning to delinquency.

Establishing thresholds for meaningful within-individual change using longitudinal item response theory

Purpose

Thresholds for meaningful within-individual change (MWIC) are useful for interpreting patient-reported outcome measures (PROM). Transition ratings (TR) have been recommended as anchors to establish MWIC. Traditional statistical methods for analyzing MWIC such as mean change analysis, receiver operating characteristic (ROC) analysis, and predictive modeling ignore problems of floor/ceiling effects and measurement error in the PROM scores and the TR item. We present a novel approach to MWIC estimation for multi-item scales using longitudinal item response theory (LIRT).

Methods

A Graded Response LIRT model for baseline and follow-up PROM data was expanded to include a TR item measuring latent change. The LIRT threshold parameter for the TR established the MWIC threshold on the latent metric, from which the observed PROM score MWIC threshold was estimated. We compared the LIRT approach and traditional methods using an example data set with baseline and three follow-up assessments differing by magnitude of score improvement, variance of score improvement, and baseline-follow-up score correlation.

Results

The LIRT model provided good fit to the data. LIRT estimates of observed PROM MWIC varied between 3 and 4 points score improvement. In contrast, results from traditional methods varied from 2 to 10 points—strongly associated with proportion of self-rated improvement. Best agreement between methods was seen when approximately 50% rated their health as improved.

Conclusion

Results from traditional analyses of anchor-based MWIC are impacted by study conditions. LIRT constitutes a promising and more robust analytic approach to identifying thresholds for MWIC.