Quality of life complements traditional outcome measures in immune-mediated polyneuropathies

Abstract

Objectives: To determine whether quality of life complements traditional outcome measures in immune-mediated polyneuropathies using the Medical Outcome Study 36-item short-form health status scale (SF-36). The validity, reliability, and responsiveness of the SF-36 were also analyzed.

Methods: SF-36 and three other measures (Medical Research Council sumscore, sensory sumscore, and Hughes functional scale) were assessed in 114 stable patients (83 with Guillain-Barré syndrome (GBS), 23 with chronic inflammatory demyelinating polyneuropathy (CIDP), eight with a gammopathy-related polyneuropathy) and serially in 20 patients with recently diagnosed GBS (n = 7) or CIDP (n = 13) with changing conditions. The SF-36 values were compared with reported healthy Dutch community scores (controls). The SF-36 validity and reliability were examined by correlation and regression studies with the other measures and by calculating its internal consistency. The standardized response mean and effect size techniques were applied to determine its responsiveness.

Results: In the stable group, all SF-36 scores were substantially lower (indicating worse clinical condition) compared with control subjects (p < 0.0001). Improvement in the longitudinal group resulted in a gradual shift of all SF-36 scores toward normal values. Acceptable validity and internal consistency values and moderate to good standardized response mean and effect size scores were demonstrated for the SF-36. The Medical Research Council sumscore and sensory sumscore explained SF-36 values only partially.

Conclusion: The SF-36 as a generic health status complemented traditional strength and sensory measures in patients with immune-mediated polyneuropathies and appears to be a potentially valuable instrument for measuring quality of life in these conditions.