Lupus Symptoms Inventory (LSI): Development and validation of a self-evaluation inventory of the subjective symptoms of systemic lupus erythematosus

The goal of this study was to develop a simple, easy, and quick self-report measure, the Lupus Symptom Inventory (LSI), designed to evaluate subjective symptoms of Systemic Lupus Erythematosus (SLE). The internal consistency of the LSI was tested, as well as its concordance with physician reports and serological indicators of disease activity by evaluating the self-reports of 46 patients with SLE who completed the LSI daily for a one-month period. Throughout this one-month period, parameters of serological activity and routine medical check-up were obtained. The results showed a high internal consistency of the LSI, with a Cronbach alpha of .86. Additionally, a contingency analysis showed agreement between medical report and patient self-report on the same day for six of seven lupus symptoms (difficulty breathing (p < .004), joint pain (p < .001), loss of appetite (p < .003), general malaise (p < .005), fatigue (p < .005), and skin rash (p < .018)) but not for abdominal symptoms. Finally, differences were found between LSI scores of patients with high versus low serological activity (χ²(1) = 5.302; p < .021), with the former presenting higher LSI scores than the latter. These results show that the LSI may be a reliable and valid instrument for evaluating the subjective symptoms of the disease as well as its fluctuations.