Nephro-Urology Unit, Institute of Child Health and 1 Department of Paediatric Rheumatology, Great Ormond Street Hospital for Children NHS Trust, London, UK.
Correspondence to: S. D. Marks, Nephro-Urology Unit, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK. E-mail: s.marks{at}ich.ucl.ac.uk
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Abstract |
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Method. Prospective observational comparison study of the BILAG index in 21 SLE patients under 18 yr of age over a 12-month period in a tertiary referral paediatric outpatient clinic.
Results. Eleven patients with lupus non-nephritis and 10 patients with lupus nephritis were reviewed. The lupus nephritis patients had significantly (P<0.001) more admissions over a similar time interval since diagnosis. The renal BILAG disease activity scores were significantly greater (P = 0.013) in the lupus nephritis group (range 19, median 3.0, compared with 03 and 1.0 in the lupus non-nephritis group). The total BILAG scores and patient visual analogue scores (VAS) were higher in the lupus nephritis groups, unlike the lower physician VAS, but these differences were not statistically significant compared with other laboratory indices of disease activity.
Conclusions. The BILAG index is a useful tool in monitoring disease activity in children and adolescents with SLE. The data collected for the BILAG index can be used serially and effectively by different clinicians over time to enable recording of disease status at sequential assessments. The lower patient VAS in the lupus non-nephritis group was not significant and may reflect the patients own perception of lethargy at times of increased disease activity.
KEY WORDS: Systemic lupus erythematosus, Childhood, Lupus nephritis, Disease activity score, BILAG index
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Introduction |
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The monitoring of outcome in lupus patients depends on the use of reproducible, reliable and validated disease activity, damage and patient health perception indices. The BILAG index is based on the principle of the physician's intention to treat, and is a clinical measure of disease activity in SLE patients which has been validated to be reliable, comprehensive and sensitive to change [1215]. It was developed to report disease activity in eight systems (general, mucocutaneous, neurological, musculoskeletal, cardiorespiratory, vasculitis, renal and haematological), which differentiates it from other lupus activity indices.
Each category has up to 18 questions, which are scored according to whether or not clinical features are present and whether they are improving (in the previous 4 weeks), the same, worse or new.
The BILAG scores include renal and haematological assessments within these systems, with confirmation of abnormal results due to active lupus (rather than drug side-effects, for example). The renal BILAG consists of assessment of blood pressure, proteinuria (dipstick and/or 24 h quantification), active urine sediment, nephrotic syndrome, renal function (creatinine and creatinine clearance or glomerular filtration rate) and histological evidence of active nephritis. The BILAG score does not include immunological data.
Although the BILAG system was originally devised for adult patients, its use has been adapted for and fully assessed in children [16]. The SDI [Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology Damage Index] [17, 18] is a damage index for lupus which has been developed and widely accepted. However, it had not yet been validated in children at the time of this trial so this assessment was not included in the present study.
The methods of assessing disease severity are always open to discussion in relation to children with lupus. Many believe that clinical assessment should take precedence over laboratory investigations. However, it is well recognized that there may be changes in the results of investigations suggesting a flare in disease activity even though the patient is clinically well, and at other times clinical evidence of disease activity without commensurate laboratory abnormalities.
The main aim of this study was to compare the validity of the BILAG index in children and adolescents with SLE between two groups of patients: those with biopsy-proven lupus nephritis and those without. Our hypothesis was that if the BILAG index is valid, then it will be scored significantly higher in those patients with lupus nephritis. We also wanted to determine the correlation between the total BILAG score and clinical and laboratory measures of disease activity [such as erythrocyte sedimentation rate, C-reactive protein, antinuclear antibody, anti-double-stranded DNA antibody, complement C3 and C4 and anticardiolipin immunoglobulin (Ig) G and IgM antibody].
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Subjects and methods |
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Due to the nature of tertiary referrals, these patients tend to be at the severe end of the spectrum of childhood disease activity. All the patients were seen at additional out-patient appointments in a joint nephrology and rheumatology clinic specifically set up for lupus patients at Great Ormond Street Hospital for Children NHS Trust for the purpose of this study. The subjects of the study were identified by a search of the hospital's Patient Information Management Systems (PIMS) and the Nephrology Patient Database.
Twenty-five lupus patients were invited to attend the clinic, of whom 21 consented: 10 patients had lupus nephritis (clinical and biopsy-proven), referred to as the lupus nephritis group, and 11 had no clinical or laboratory evidence of renal involvement at the time of analysis, referred to as the lupus non-nephritis group.
Full clinical assessment (history, examination and investigations) was undertaken on all patients. The severity of disease activity in the cases was analysed manually using version 3 of the BILAG index [13] assessment form, which rates clinical and laboratory manifestations in each of the eight organ systems.
To provide numerical scores, we used a previous weighting system that assigned a score of 9 to active manifestations (grade A in the BILAG), 3 to grade B manifestations, 1 to grade C manifestations, and 0 to grade D and E manifestations. We used the sum of these scores as a summary index (possible range 072) [15].
One unblinded physician (S.D.M.) and all patients completed visual analogue scales (VAS); the patients marked on a 10-cm scale how well they felt in general, 0 denoting very ill and 10 denoting completely well [19].
The data were analysed with SPSS 11.0 software for Windows. Statistical significance was derived using non-parametric tests such as the MannWhitney U, Wilcoxon W and KruskalWallis tests.
Ethical approval was obtained for this study from the Institute of Child Health and Great Ormond Street Hospital for Children NHS Trust Research Ethics Committee, and written consent was obtained for all cases.
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Results |
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Laboratory measures of disease activity
The findings from this study (Table 4) showed no statistically significant differences between the groups. The lupus non-nephritis group, however, were more likely to have higher anticardiolipin IgG antibodies, which would suggest an increased likelihood of thrombotic events, although this was not statistically significant.
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Discussion |
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All of the information from the history, examination and the evaluation of laboratory evidence of disease activity is required for optimal management. The BILAG has been shown to be highly sensitive to clinical change in children and can be used to study the response to treatment in children with SLE [16], which can be beneficial in randomized controlled studies of different therapeutic regimens.
The methods of assessing disease severity in childhood SLE are still open to discussion. Scales of indices of disease activity continue to evolve and include SLEDAI (Systemic Lupus Erythematosus Disease Activity Index), SLAM (Systemic Lupus Activity Measure) and ECLAM (European Consensus Lupus Activity Measure) [1618, 20, 21]. These have all been used in the evaluation of disease activity in adults and are being validated for use in children with SLE.
In our study, the lower patient VAS values in the lupus non-nephritis group are not significant and may reflect the patients own perception of lethargy at times of increased disease activity. Patients and physicians assess disease activity differently using the 10-cm VAS; as expected, physicians place more emphasis on laboratory features, whereas patients emphasize function [19]. This may explain the differences seen between the physician and patient VAS results.
This study is limited by the relatively small number of patients reviewed with regard to the BILAG index, patient and physician VAS. All of this needs to be re-assessed frequently with more patients as part of a multicentre study.
SLE is a multisystem disease that can affect different systems over time, and therefore physicians need to continuously assess clinical and laboratory results to monitor disease activity. Documentation in the notes of clinical symptoms and signs is, therefore, imperative in the management of children with SLE.
However, problems can be encountered when different physicians are assessing patients at out-patient clinic attendances and during admissions. The BILAG index allows effective monitoring of disease progress serially over time by using standardization of questions and data recorded, even if patients are seen by different clinicians.
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The authors have declared no conflicts of interest.
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References |
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