OBJECTIVE: At OMERACT 8 a framework for levels of evidence was proposed for the validation of biomarkers as surrogate outcome measures. We aimed to adapt this scheme in order to apply it in the setting of soluble biomarkers proposed to replace the measurement of damage endpoints in rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS). We also aimed to generate consensus on minimum standards for the design of longitudinal studies aimed at validating biomarkers.

METHODS: Before the meeting, the Soluble Biomarker Working Group prepared a preliminary framework and discussed various models for association and prediction related to the statistical strength domain. In addition, 3 Delphi exercises addressing longitudinal study design for RA, PsA, and AS were conducted within the working group and members of the Assessments in SpondyloArthritis International Society (ASAS) and the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA). This formed the basis for discussions among OMERACT 9 participants.

RESULTS: The proposed framework was accepted by consensus. In the study design domain a requirement for both prospective observational studies and randomized controlled trials (RCT) in different drug classes was noted. A template for determining the level of statistical strength was proposed. The addition of a new domain on biomarker assay performance was considered essential, and participants suggested that for any biomarker this domain should be addressed first, i.e., before starting clinical validation studies. Participants agreed on most elements of a longitudinal study design template. Where consensus was lacking the working group has drafted solutions that constitute a basis for prospective validation studies.

CONCLUSION: The OMERACT 9 Soluble Biomarker Group has successfully formulated a levels of evidence scheme and a study design template that will provide guidance to conduct validation studies in the setting of soluble biomarkers proposed to replace the measurement of damage endpoints in RA, PsA, and AS.

To test the hypothesis that fibromyalgia (FM) patients with reduced lower extremity strength are more symptomatic and tender than FM patients with normal muscle strength.

Smoking and hazardous drinking are common and important risk factors for an increased rate of complications after surgery. The underlying pathophysiological mechanisms include organic dysfunctions that can recover with abstinence. Abstinence starting 3-8 weeks before surgery will significantly reduce the incidence of several serious postoperative complications, such as wound and cardiopulmonary complications and infections. However, this intervention must be intensive to obtain sufficient effect on surgical complications. All patients presenting for surgery should be questioned regarding smoking and hazardous drinking, and interventions appropriate for the surgical setting applied.