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The size of the treatment effect: do patients and proxies agree?

Femke A H van der Linden1, Jolijn J Kragt, Jeremy C Hobart

  • 1Department of Neurology, VU University Medical Centre, Amsterdam, The Netherlands. fah.vdlinden@vumc.nl

BMC Neurology
|March 26, 2009
PubMed
Abstract

Insights

Proxy respondents largely agree with Multiple Sclerosis Impact Scale (MSIS-29) patient assessments of treatment change, suggesting their utility in group-level evaluations, especially when patient self-assessment is challenging.

Area of Science:

  • Neurology
  • Clinical Research
  • Patient-Reported Outcomes

Background:

  • Assessing treatment-induced changes in disease impact for Multiple Sclerosis (MS) patients can be challenging.
  • Cognitive impairment or other limitations may affect reliable patient self-assessment.
  • Proxy respondents may offer an alternative perspective on disease impact changes.

Purpose of the Study:

  • To evaluate the agreement between MS patients and their proxy respondents regarding changes in disease impact after treatment.
  • To determine if proxy assessments using the MSIS-29 align with patient-reported changes.
  • To explore the diagnostic utility of the MSIS-29 when completed by patients versus proxies.

Main Methods:

  • Patients and proxies completed the Multiple Sclerosis Impact Scale (MSIS-29) pre- and post-intravenous steroid treatment.
  • Analysis focused on patient-proxy agreement in MSIS-29 change scores.
  • Receiver operating characteristic (ROC) analyses assessed the diagnostic properties of the MSIS-29 for both patient and proxy completions.

Main Results:

  • Patient-proxy differences in MSIS-29 change scores were small, with considerable variability noted.
  • The direction of mean change reported by patients was consistent with proxy ratings.
  • ROC analyses showed similar diagnostic performance for the MSIS-29 when completed by patients and proxies.

Conclusions:

  • Proxy respondents demonstrate potential utility in assessing patient-perceived treatment changes at a group level.
  • Findings suggest that proxy assessments can complement patient self-reports, particularly in cases of impaired self-assessment.
  • Further validation in larger cohorts is recommended to solidify the role of proxy respondents.

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