Table 1

Definitions and considerations for each domain*

Domain†Definitions and special considerations
1. Pattern of joint/bursa involvement during symptomatic episode(s) ever
 Categories are defined as per the description of the distribution of joints involved
Distribution of joints: involvement (ever) of
  •   1. Joint(s) or bursa(e) other than ankle, mid-foot or first metatarsophalangeal (MTP) joint (or their involvement only as part of a polyarticular presentation)

  •   2. Ankle or mid-foot joint(s) as monoarticular or part of an oligoarticular presentation without first MTP joint involvement

  •   3. MTP joint involvement as monoarticular or part of an oligoarticular presentation

2. Characteristics of symptomatic episode(s) ever
 Categories are defined as
  •    No characteristics present

  •    1 characteristic present

  •    2 characteristics present

  •    3 characteristics present

Characteristics to consider: presence (ever) of
  •   1. Great difficulty with walking or inability to use the affected joint(s) during a symptomatic episode ever (patient-reported)

  •   2. Can't bear touch or pressure to the affected joint during a symptomatic episode ever (patient-reported)

  •   3. Erythema overlying affected joint during a symptomatic episode ever (patient-reported or physician-observed)

3. Time course of symptomatic episode(s) ever
 Categories are defined as
  •    No typical episodes

  •    1 typical episode

  •    Recurrent typical episodes

‘Typical symptomatic episode’: presence (ever) of >2 of the following, irrespective of anti-inflammatory treatment
  •   1.Time to maximal pain <24 h

  •   2. Resolution of symptoms in ≤14 days

  •   3. Complete resolution (to baseline level) between symptomatic episodes

4. Clinical evidence of tophus
 Categories are defined as
  •    Present

  •    Absent

Appearance: draining or chalk-like subcutaneous nodule under transparent skin, often with overlying vascularity (figure 2)
Location: classic locations—joints, ears, olecranon bursae, finger pads, tendons (eg, Achilles)
5. Serum urate level, off-treatment
 Categories are defined as
  •    <4 mg/dL (0.24 mmol/L)

  •    4–<6 mg/dL (0.24–<0.36 mmol/L)

  •    6–<8 mg/dL (0.36–<0.48 mmol/L)

  •    8–<10 mg/dL (0.48–<0.60 mmol/L)

  •    ≥10 mg/dL (≥0.60 mmol/L)

Which serum urate measurement to use: highest reading on record, off urate-lowering therapy
Special considerations: Ideally, the serum urate level should be scored if tested at a time when the patient was not receiving urate-lowering therapy and it was >4 weeks from the start of an episode; if practicable, retest under those conditions. If serum urate level is ≥10 mg/dL, no need to retest
6. Synovial fluid analysis
 Categories are defined as
  •    MSU negative

  •    Not done

Location: symptomatic (ever) joint or bursa
Special considerations: assessment should be performed by a trained observer
Note: MSU positive is a sufficient criterion.
7. Imaging evidence of urate deposition
 Categories are defined as
  •    Absent or not done

  •    Present (either modality)

Modality: ultrasound or DECT
Appearance: double-contour sign on ultrasound (figure 3A)‡ or urate deposition on DECT (figure 3B)§
Location: symptomatic (ever) joint or bursa
8. Imaging evidence of gout-related joint damage
 Categories are defined as
  •    Absent or not done

  •    Present

Modality: radiography
Appearance of gout-related erosion: cortical break with sclerotic margin and overhanging edge; excludes gull wing appearance (figure 3C)
Location: radiograph of hands and/or feet; excludes distal interphalangeal joints
  • *Symptomatic (ever) refers to pain and/or swelling.

  • †Categories within each domain are hierarchical; if a subject fulfills more than 1 category, the highest category should be selected.

  • ‡A false-positive double-contour sign (artifact) may appear at the cartilage surface, but should disappear with a change in the insonation angle of the probe.31 ,32

  • §Images should be acquired using a dual-energy computed tomography (DECT) scanner, with data acquired at 80 kV and 140 kV and analysed using gout-specific software with a 2-material decomposition algorithm that color-codes urate.33 A positive scan result is defined as the presence of color-coded urate at articular or periarticular sites. Nailbed, submillimeter, skin, motion, beam hardening, and vascular artifacts should not be interpreted as DECT evidence of urate deposition.34