Background/Purpose:   Extending lupus research outside of the clinical setting remains a challenge, in part due to the complexity of measuring disease damage.  Previously, we developed and validated a patient-reported measure of lupus damage (BILD) for research purposes.  Here we report additional validation of the BILD, focusing on its ability to detect change.

Methods:   Data were drawn from the UCSF Lupus Outcomes Study (LOS), in which participants are interviewed by phone annually.  The BILD was administered in 2 waves, 5 years apart.  Only participants who were interviewed in both years are included in the analysis (n=740). We calculated changes in BILD scores, and categorized increases in scores as 0, 1, 2, 3, or >3.  (Only increases in scores are possible because, by definition, damage cannot be reversed.)  We then examined changes in disease activity measured with the Systemic Lupus Activity Questionnaire (SLAQ), changes in the number of physician visits, and number of hospitalizations in the years between the two BILD administrations.  These measures were chosen because the disease manifestations included in the BILD would likely give rise to increased symptoms or utilization at the time they occur.  Increases in SLAQ and physician visits were defined by an increase of 0.5 standard deviation over baseline in at least one interview wave during the 5-year observation period, equivalent to an increase of 4 points on the SLAQ and 5 physician visits.  For hospitalizations, we examined the occurrence of 2+ hospitalizations in at least one wave. 

Results:   BILD scores ranged from 0-13 with a median of 1 (IQR 0-3) in the first administration.  At the second administration, scores ranged from 0-15 with a median of 2 (IQR 1-4).  Changes in BILD ranged from 0-8 with a median of 1 (IQR 0-1).  Of the 740 LOS participants, 369 had no increase in BILD score.  Of the remaining participants, 210, 84, 41, and 36 had increases of 1, 2, 3, and >3 points, respectively (Table).  Overall, 37% of LOS participants had an increase in SLAQ , 43% had an increase in physician visits, and 14% had 2+ hospitalizations in at least one interview wave. For SLAQ scores, the prevalence of an increase was highest among participants with changes in BILD ≥3.  There was a greater prevalence of increased physician visits among participants with a change in BILD >0.  Greater increases in BILD were associated with significantly greater likelihood of at least one year with 2+ hospitalizations.

 

Table.  Increases in disease activity and physician visits and hospitalizations associated with increases in BILD scores
		Increase in BILD
	Total (n=740)	0 (n=369)	1 (n=210)	2 (n=84)	3 (n=41)	>3 (n=36)	p*
SLAQ (at least 1 score > baseline by 0.5 SD)	37%	34%	40%	36%	39%	50%	.06
MD visits (at least 1 wave > baseline by 0.5 SD)	43%	36%	50%	44%	56%	47%	.0057
Hospitalizations (at least 1 wave with 2+)	14%	5%	19%	15%	29%	55%	<.0001
* p value from c2 for trend

Conclusion: Change in BILD score corresponds with increases in disease activity and physician visits and with hospitalizations that are likely to reflect disease manifestations that could cause increases in disease damage.  Previous cross-sectional examination of the BILD showed concurrent validity; this analysis provides evidence of the BILD’s ability to detect change.  While not intended to replace clinical evaluation of disease damage, the BILD does appear to be a useful tool for research.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-brief-index-of-lupus-damage-a-patient-reported-measure-of-lupus-damage-is-sensitive-to-change/