How do we measure up?
Authors: Animesh A Sinha
Journal: The Lancet (2000)

There are complex diseases, and there are complex diseases. Lupus erythematosus, named by Cazenave in 1852,1Cazenave PLA Chausit M Du Lupus (H Frey, transl).Ann Malad Peau Syph. 1852; 4: 113Google Scholar spans an incredible variety of forms, degrees, and manifestations. Such extensive clinical heterogeneity has a profound impact on disease classification, diagnosis, and therapy, and on the understanding of underlying disease mechanisms. The 1982 revised criteria for the classification of systemic lupus erythematosus (SLE)2Tan EM Cohen AS Fries JF et al.The 1982 revised criteria for the classification of systemic lupus erythematosus.Arthritis Rheum. 1982; 25: 1271-1277Crossref PubMed Scopus (12759) Google Scholar are well-accepted diagnostic standards. There are also about 60 other scales for the assessment of the extent and severity of SLE. Would they be useful in the assessment of cutaneous lupus erythematosus, for which there is no specific scale? Aurora Parodi and colleagues3Parodi A Massone C Cacciapuoti M et al.Measuring the activity of the disease in patients with cutaneous lupus erythematosus.Br J Dermatol. 2000; 142: 457-460Crossref PubMed Scopus (71) Google Scholar have applied the Systemic Lupus Activity Measure (SLAM) to the assessment of cutaneous lupus. The wide range of cutaneous findings in lupus erythematosus can be categorised as being lupus-specific (and acute, subacute, or chronic) or lupus non-specific. Moreover, the cutaneous lesions may occur with or without systemic signs or symptoms. SLAM defines just four types of skin lesions. Parodi and colleagues extended their analysis outside the scale to assess seven distinct skin findings. Although the scores seemed to be of some prognostic value for patients at greatest risk of progressing to systemic disease, Parodi and colleagues rightly conclude that SLAM is “far from being fully satisfactory” for cutaneous lupus. Certainly, SLAM must be re-focused to maximise its usefulness in cutaneous disease. An important function of standardised measures of disease is to guide therapeutic decision-making and to provide an objective supplement to subjective assessment based on personal experience. Clinical scales do not generally distinguish disease severity from disease activity. Measures of existing damage cannot be useful in decisions about which treatments may prevent the damage. With SLAM each of 24 clinical features must be deemed active before a severity score can be assigned. However, the weighting of activity relative to severity in SLAM is arbitrary, and the assignment of severity is subjective. Ideally, a clinical scale should be of dual relevance—it should reflect what is important for the physician and for the patient. Quantification of disease activity and severity should be thrown into the mix along with level of functioning and quality-of-life assessments. No matter how well formulated a disease scale may be, it must be reliable (provide reproducible results) and valid (measure what it is supposed to measure). SLAM rates highly for inter-visit and inter-rater reliability, but was not tested by Parodi and colleagues for cutaneous lupus. As a general principle, reliability should be checked for each new application of a given scale. Determining validity presents an even bigger challenge. Wherever possible, every effort should be made to compare new or modified scales with related systems. A detailed and comprehensive scale can be of potential benefit only if it is used. The Psoriasis Area and Severity Index (PASI), well known among dermatologists, is routinely used in research studies yet is not a mainstay of clinical practice. Likewise, the numerous acne scales are virtually absent from daily use because they are too cumbersome for what is a common and generally well-managed disorder. Thus, care must be taken to construct user-friendly systems. Disease scales are especially suited for tracking morbidity and mortality, quality of life, and response to treatment. They may even prove valuable for basic researchers attempting to unravel complex genetic and molecular mechanisms blurred by clinical heterogeneity. Presumably, all this information should ultimately improve the accuracy of predictions of the course of disease and the formulation of rational therapeutic plans. For many diseases, these goals have yet to be attained. Attempting to measure disease activity objectively in patients with cutaneous lupus is a step, or at least half a step, in the right direction. The changing global context of public healthFuture health prospects depend increasingly on globalisation processes and on the impact of global environmental change. Economic globalisation—entailing deregulated trade and investment—is a mixed blessing for health. Economic growth and the dissemination of technologies have widely enhanced life expectancy. However, aspects of globalisation are jeopardising health by eroding social and environmental conditions, exacerbating the rich-poor gap, and disseminating consumerism. Global environmental changes reflect the growth of populations and the intensity of economic activity. Full-Text PDF