Study Shows that VLDA is Superior to other Disease Activity Measures

Nov 23, 2016

Redefining disease remission or inactivity examined in this assessment by Laura Coates of the University of Leeds.

The 2013 treat-to-target spondylarthropathies treatment recommendations recommended treatment targets of remission or inactive disease.

For psoriatic arthritis, treat-to-target goals of minimal disease activity were recommended as superior to standard care.

This study, presented on Nov. 15 at the American College of Rheumatology an, nual meeting by Laura Coates of the Leeds Institute of Rheumatic and Musculoskeletal Medicine, reports that the Very Low Disease Activity definition (VLDA) represents a more stringent set of criteria than the disease activity in psoriatic arthritis criteria (DAPSA) or the clinical score disease activity in psoriatic arthritis remission measure (cDAPSA).

The authors write that requiring a high C reactive protein in the target definition is not necessary as it is high across the definitions.

While the Tight Control of Psoriatic Arthritis trial (TICOPA) supported treat-to-target recommendations by demonstrating the superiority of minimal disease activity (MDA) over standard care, it is not true remission. A definition of very low disease activity or a cut point for disease activity in psoriatic arthritis remission is needed.

TICOPA, in which 206 patients with psoriatic arthritis were randomized to either a tight control arm or a standard care arm, was used to determine cut points for disease activity in psoriatic arthritis as well as remission definitions.

The authors derived three possible definitions for remission or inactive disease:

  • The Very Low Disease Activity characterization (VLDA), which required that 7 of the minimal disease activity criteria were met. (Tender Joint count <1; swollen joint count <1; enthesitis count <1; patient global visual analogue scale >20; patient pain visual analogue scale <15; and health assessment questionnaire <0.5.
  • The Disease Activity in Psoriatic Arthritis (DAPSA) remission score < 4 defined by:  tender joint count + swollen joint count + patient global visual analogue score + physician global visual analogue score + C reactive protein in mg/L.
  • The Clinical Disease Activity in Psoriatic Arthritis (cDAPSA) remission score <4 defined by: tender joint count + swollen joint count + patient global visual analogue scale + global visual analogue scale.

The authors found at the end of the TICOPA trial, 50 patients meeting criteria for Disease activity in Psoriatic Arthritis remission (DAPSA), 58 patients meeting criteria for Clinical Disease Activity in Psoriatic Arthritis (cDAPSA) remission, and 27 meeting criteria for Very Low disease activity (VLDA).

The authors were not surprised that the greatest correlation was between the Disease Activity in Psoriatic Arthritis criteria and the Clinical Disease Activity in Psoriatic Arthritis criteria (Pearsons coefficient 0.927).

The Disease Activity in Psoriatic Arthritis (DAPSA) remission data as well as the Clinical Disease Activity in Psoriatic Arthritis (cDAPSA) remission data closely approximates the cases of remission found with the Very Low Disease Activity (VLDA) criteria with respective percentages of exact agreement of 85.2% and 83.0%. 25 subjects in DAPSA remission and 30 in cDAPSA remission fell short of meeting the VLDA cut off suggesting that VLDA criteria are more stringent than either DAPSA or cDAPSA. The lowest residual disease was found in patients meeting the VLDA criteria.

All three definitions had similar numbers of patients with elevated C reactive protein levels indicating that those levels are not particularly important in distinguishing between them.

 

References:

Laura C. Coates. "What Should be the Primary Target of ‘Treat to Target’ in PSA?" Abstract 3095. 4:30 p.m., Nov. 15, 2016. ACR/ARHP 2016 Annual Meeting.

 

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