Abstract: Minimal Clinically Important Difference, Low Disease Activity State, and Patient Acceptable Symptom State: Methodological Issues

Minimal Clinically Important Difference, Low Disease Activity State, and Patient Acceptable Symptom State: Methodological Issues

FLORENCE TUBACH, GEORGE A. WELLS, PHILIPPE RAVAUD, and MAXIME DOUGADOS

ABSTRACT.

The importance of determining a minimal clinically important difference (MCID) and a low disease activity state (LDAS) as treatment targets in clinical trials no longer needs to be demonstrated. However, many methodological issues remain: whether these thresholds should be defined for each criterion or for composite criteria, whether there is a difference between the LDAS and patient acceptable symptom state (PASS), how to determine these thresholds (i.e., the wording of the questions and the statistical approach), and whether there are confounding factors in their evaluation. We consider these methodological issues and discuss their impact. Methods to determine the thresholds must be standardized, and recommendations could be endorsed by an OMERACT module. Threshold values for the MCID and LDAS should be determined according to data-driven and experts' opinions and approaches. (J Rheumatol 2005;32:2025-9)

Key Indexing Terms:

MINIMAL CLINICALLY IMPORTANT DIFFERENCE
DISEASE ACTIVITY
LOW DISEASE ACTIVITY STATE
OUTCOME ASSESSMENT
PATIENT PERSPECTIVE

From the Département d'Epidémiologie, Biostatistique et Recherche Clinique, Groupe Hospitalier Bichat-Claude Bernard (AP–HP), INSERM U738, Faculté Xavier Bichat (Université Paris 7), Paris, France; Department of Clinical Epidemiology and Community Medicine, University of Ottawa, Ottawa, Canada; and Service de Rhumatologie B, Hôpital Cochin (AP–HP), Paris, France.

F. Tubach, MD, INSERM U738, Département d'Epidémiologie, Biostatistique et Recherche Clinique, Groupe Hospitalier Bichat-Claude Bernard, Faculté Xavier Bichat; G.A. Wells, PhD, Department of Clinical Epidemiology and Community Medicine, University of Ottawa; P. Ravaud, MD, PhD, INSERM U738, Département d'Epidémiologie, Biostatistique et Recherche Clinique, Groupe Hospitalier Bichat-Claude Bernard, Faculté Xavier Bichat; M. Dougados, MD, Service de Rhumatologie B, Hôpital Cochin.

Address reprint requests to Dr. F. Tubach, Département d'Epidémiologie, Biostatistique et Recherche Clinique, INSERM U738, Hôpital Bichat, 46 rue Henri Huchard, 75018 Paris, France.