Esdaile J M, Abrahamowicz M, Joseph L, MacKenzie T, Li Y, Danoff D
Montreal General Hospital, McGill University, Quebec, Canada.
Arthritis Rheum. 1996 Mar;39(3):370-8. doi: 10.1002/art.1780390304.
To evaluate whether changes in laboratory test values are either simultaneous with or precede disease exacerbations in patients with systemic lupus erythematosus (SLE).
At 9, 6, and 3 months preceding a flare in disease activity (defined as a rise of > or = 6 points in the modified SLE Disease Activity Index), laboratory tests were performed to measure patients' hematocrit levels, white blood cell, lymphocyte, and platelet counts, erythrocyte sedimentation rate, C1q binding, DNA binding, and levels of C3 and C4. Flares were classified as either present or absent, and were divided into renal, vasculitic, central nervous system, skin, serosal, and musculoskeletal subgroups. The predictive patterns were 1) the simultaneous change in the test value from the mean of 9, 6, and 3 months preceding a flare to the time of the flare; 2) the gradual change, following a linear time trend, in test results for the same time points; and 3) the change from the mean of 9 and 6 months to 3 months preceding a flare, as a measure of predictive ability. These analyses used repeated-measures analysis of variance models. Multiple linear regression was used to study the cross-sectional association of average-over-time differences in test results with patients' flare subgroup.
Among 202 patients with SLE (median followup 86.5 months), 83 flares occurred in 53 patients. Of 189 statistical contrasts performed, only 14 were significant (versus 10 expected), and the differences were of minor importance. Nonetheless, evaluation of all test results over each patient's observed disease course revealed significant differences between selected test values in association with specific types of flare.
Fluctuations in laboratory test values are poor predictors of disease exacerbations in SLE. Cross-sectional evaluation of some test results revealed differences at the time of flare for those patients who were destined to have different types of flares, because these values differed over the entire study period. This pattern explains the frequent cross-sectional association of disease activity with laboratory test results, and the inconsistent association of flares with recent changes in test values.
评估系统性红斑狼疮（SLE）患者实验室检查值的变化是与疾病加重同时出现还是先于疾病加重。
在疾病活动度 flare（定义为改良SLE疾病活动指数升高≥6分）前9、6和3个月进行实验室检查，以测量患者的血细胞比容水平、白细胞、淋巴细胞和血小板计数、红细胞沉降率、C1q结合、DNA结合以及C3和C4水平。Flares分为出现或未出现，并分为肾脏、血管炎、中枢神经系统、皮肤、浆膜和肌肉骨骼亚组。预测模式为：1）从flare前9、6和3个月的平均值到flare发生时检查值的同时变化；2）在相同时间点，检查结果遵循线性时间趋势的逐渐变化；3）从flare前9和6个月的平均值到3个月的变化，作为预测能力的一种衡量。这些分析使用重复测量方差分析模型。多元线性回归用于研究检查结果随时间的平均差异与患者flare亚组的横断面关联。
在202例SLE患者（中位随访86.5个月）中，53例患者出现了83次flare。在进行的189次统计对比中，只有14次显著（预期为10次），且差异不太重要。尽管如此，对每位患者观察到的疾病过程中的所有检查结果进行评估发现，特定类型flare相关的选定检查值之间存在显著差异。
实验室检查值的波动对SLE疾病加重的预测能力较差。对一些检查结果的横断面评估显示，对于那些注定会出现不同类型flare的患者，在flare发生时存在差异，因为这些值在整个研究期间都有所不同。这种模式解释了疾病活动度与实验室检查结果之间频繁的横断面关联，以及flare与检查值近期变化之间不一致的关联。
