Abstract
Introduction/Aim:
The use of outcome measures is recommended for chronic inflammatory demyelinating polyneuropathy (CIDP). Implications of minimal important differences (MID) to ascertain responder status are unknown. The reliability of patient-reported treatment-response in relation to clinically relevant change is also unknown.
Methods:
We retrospectively studied 72 subjects with “definite” or “probable” CIDP evaluated at pre-specified time-intervals pre- and post-treatment. We derived MID and the minimum detectable change with 95% confidence intervals (MDC95) for four scales. Scale sensitivities were determined with applicable MID-defined cutoffs (aMIDc), to detect subjects with self-identifying treatment response through a single question.
Results:
The use of MID was not valid for the Medical Research Council Sum Score, as MDC95 > MID. The aMIDc for the Overall Neuropathy Limitation Score (ONLS) was 1 (sensitivity: 84.7%). The aMIDc for the centile Inflammatory Rasch-built Overall Disability Scale (cI-RODS) was 8 (sensitivity: 62.3%). The aMIDc for grip strength was 4 kg (sensitivity: 79.1%). MID-defined amelioration of any one scale among ONLS, cI-RODS, or grip strength, significantly improved sensitivity to detect treatment-responders compared with the ONLS alone (McNemar test: P = .008, odds ratio: 3.36 [95% confidence interval: 1.44–7.86]). Patient-reported improvement was highly reliable in relation to MID-defined amelioration on any one scale.
Discussion:
In subjects with CIDP, MID-defined amelioration of any one of three commonly used outcome measures offers optimum relevance and sensitivity to detect self-identifying treatment-responders. Patient reliability to single-question ascertainment of response is high in relation to MID-defined clinical relevance. These findings support use of multiple outcome measures in CIDP monitoring and justify enhanced patient involvement in the process.
Original language | English |
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Pages (from-to) | 37-42 |
Number of pages | 6 |
Journal | Muscle and Nerve |
Volume | 64 |
Issue number | 1 |
Early online date | 9 Apr 2021 |
DOIs | |
Publication status | Published - Jul 2021 |
Keywords
- chronic inflammatory demyelinating polyneuropathy
- minimum detectable change
- minimum important difference
- outcome measures
- responders
- self-identifying
- sensitivity