86.- The state of the art in the damage index development and utility
The improved survival noted among patients with SLE indicates that it would be difficult to perform outcome because of its rate occurrence. Disease activity, particularly when individual organs are considered, may result in specific organ damage and morbidity, causes of death in patients who survive longer than 10 years tend to be other than active SLE.1
At a Conference on Prognosis Studies in SLE convened in Toronto in 1985, the participants, a group of clinicians and methodologists who have been working on disease activity in SLE, concluded that in order to describe prognosis in SLE, the disease activity, accumulated damage, and health status of the patient need to be evaluated.2,3
Prior to the 1985 Conference on Prognosis studies, the participants were asked to assess items which might be included in a damage index or importance.3 A list of items that should be included in the a damage index, with some definitions for ascertainment was generated.
These documents were reviewed by the participants of a subsequent conference, held in Boston in 1991. The participant included rheumatologist who have previously worked on the assessment of damage in SLE, in addition to the members of the NATO group. They submitted their comments and suggestions for inclusion or exclusion of certain items in the documents. The aim of the conference was to review previous work on the damage index, to assess whet her the suggested items for the index were variables which could be detected in patient profiles, and to develop an index which could be rested for validity, reproducibility and sensitivity to change.
In order to familiarize the participants with the concepts included in the damage list, as well as to test whether these variables were easily detectable, 20 patient profiles which reflected accumulated damage were prepared, and each participant completed a damage index for each of these patients. The reports were entered into a computer and analysed. Analysis of variance for the overall score or the damage index revealed patient variability, suggesting that the patient profiles chosen reflected variability of damage. There was, however, a significant variation among the raters. The participants reviewed the results and discussed the items which caused most disagreement. It was felt that the major reason for lack of agreement during the rating exercise resulted from the fact that no definitions had been included with the index.
A further study was designed in which the participant reviewed case scenarios of patients with at least 5 years of disease, but with varying degree of damage in the context of either active or inactive disease. The analysis of the study revealed that the damage index could identify patients with damage, was distinct from the activity status of the patient. It showed that the variability caused by the physician assessors was very small, thus the SLICC damage index was validated. Further studies are under way to assess the value of weighting the index.
The instrument has now been administered to several groups of patients, including patients in Toronto, Baltimore, New York, and Boston, and has been shown to identify damage in these patients. It is now ready for more wide testing form validity, reproducibility and sensitivity to change. These studies are currently in progress by the members of the SLICC.
Gladman DD: Prognosis of SLE and factors that affect it. Systemic lupus erythematosus and Sjogren‘ s syndrome. Edited by Talal N. Cuit Opin Rheumatol 1991 3(5): 786-789.
Conference on Prognosis studies in SLE: Prognosis studies in SLE: an activity index (abstract). Arthritis Rheum 1986; (suppl 4): 593
Urowitz MB. Late mortality and morbidity. Proceedings of the 2nd International Conference on Systemic Lupus Erythematosus. Professional Post – graduate Services International 1989; 190-193.
Gladman DD, Urowitz MB. Assessment of Disease Activity in SLE. Transfusion Science 1992.
Isenberg D, Bacon P. Bomhardier C, et al: Criteria for assessing disease activity in systemic lupus erythematosus. J Rheumatol 1989; 16: 1395-1396.
Gladman DD, Goldsmith CII, Urowitz MB3, et al: Crosscultural validation and reliability of three disease activity indices in SLE. JR heumatol (In press).
Gladman D, Goldsmith C, Urowitz M, Bacon P, Bombardier C, Isenberg D, Kalunian K, Liang M, Maddison P, Nived 0, Richter M, Snaith M, Symmons D, Zoma A. Sensitivity to change of 3 SLE disease activity indices: International validation. Arthritis Rheum 1990; 33 (9 suppl): 582.