Development and validation of the Lupus Impact Tracker: a patient-completed tool for clinical practice to assess and monitor the impact of systemic lupus erythematosus.
OBJECTIVE
To derive and validate a brief patient-completed instrument, the Lupus Impact Tracker (LIT), to assess and monitor the impact of systemic lupus erythematosus (SLE).


METHODS
Items for the LIT were selected from the LupusPRO, a validated patient-reported outcomes measure, using 3 approaches: confirmatory factor analysis (CFA), stepwise regression, and patient focus groups. CFA was conducted to find items from the LupusPRO that fit a unidimensional structure to allow scoring as a single index. Stepwise regression methods identified items with the strongest relationship (convergent validity) with disease activity measures and patient health rating. Focus groups (n = 26 patients) identified the most important items describing SLE impact. Selected items were evaluated for reliability and validity.


RESULTS
CFA found 21 items that fit a unidimensional structure. Stepwise regressions identified 15 of 21 items having good convergent validity with clinical measures. Patient focus groups identified 9 of 15 items as best capturing the impact of SLE. Overall, 7 items were selected across all 3 approaches (CFA, stepwise regression, and focus groups). Another 15 items were selected across 2 approaches. Through consensus with rheumatology clinician experts, a final set of 10 items was selected for the LIT. The LIT items showed good internal consistency (0.89) and test-retest reliabilities (0.87). Mean LIT scores differed significantly (P < 0.05) across criterion groups in the hypothesized direction, providing evidence of discriminant validity and responsiveness.


CONCLUSIONS
The LIT is reliable and valid in SLE patients and offers a practical way for physicians and patients to assess and monitor the impact of SLE.
Rush University Medical Center, Chicago, Illinois.
Meenakshi
M
Jolly
Cindy P
CP
Garris
Rachel A
RA
Mikolaitis
Priti M
PM
Jhingran
Greg
G
Dennis
Daniel J
DJ
Wallace
Ann
A
Clarke
Mary Anne
MA
Dooley
Ann
A
Parke
Vibeke
V
Strand
Graciela S
GS
Alárcon
Mark
M
Kosinski
D000328:Adult; D017281:Cost of Illness; D005163:Factor Analysis, Statistical; D005260:Female; D017144:Focus Groups; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012044:Regression Analysis; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D014481:United States