Validity and reliability of the proposed American College of Rheumatology neuropsychological battery for systemic lupus erythematosus: Comment on the article by Kozora et al

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Validity and Reliability of the Proposed American College of Rheumatology Neuropsychological Battery for Systemic Lupus Erythematosus: Comment on the Article by Kozora et al

To the Editor:

In a recent article, Kozora et al noted that, to date, no studies have examined the statistical properties (reliability and validity) of the ACR-SLE battery in patients with SLE (both with and without a history of neuropsychiatric SLE) compared with controls (Kozora E, Ellison MC, West S. Reliability and validity of the proposed American College of Rheumatology neuropsychological battery for systemic lupus erythematosus. Arthritis Rheum 2004;51:810–8). However, we previously reported our findings relative to the validity of the American College of Rheumatology (ACR) criteria for neuropsychiatric systemic lupus erythematosus (NPSLE) (Ainiala H, Hietaharju A, Loukkola J, Peltola J, Korpela M, Metsanoja R, et al. Validity of the new American College of Rheumatology criteria for neuropsychiatric lupus syndromes: a population-based evaluation. Arthritis Rheum 2001;45:419–23). We are aware that in their study, Kozora et al concentrated their efforts on neuropsychological batteries of tests only, and we studied the validity of all proposed criteria in 19 NPSLE syndromes. Our main finding was that the proposed ACR criteria did not differentiate patients with SLE from controls or patients with NPSLE from other patients with SLE. Cognitive dysfunction was significantly more common in patients with SLE than in controls, but the inclusion of mild cognitive impairment, i.e., deficits in fewer than 3 cognitive domains in the comprehensive neuropsychological battery of tests, resulted in low specificity of the criteria in patients compared with that in matched controls.

Our evaluation, which was based on a comparison of patients with SLE and control subjects without SLE, provided information about validity, i.e., capability of the ACR criteria to distinguish between patients with SLE from subjects without SLE. We believe this is much more useful than a correlation between different measures of disease impact (measures for assessment of neuropsychological impact) from the ACR-SLE battery and a 4-hour comprehensive battery. This approach applied in the study by Kozora et al comprising 31 patients with NPSLE, 22 patients with SLE without NP symptoms, and 25 healthy controls would have provided clinically useful information about the discrimination capability of the 2 test batteries.

Aki Hietaharju MD, PhD*, Anssi Auvinen MD, PhD*, * Tampere University Hospital Tampere, Finland.

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