Table 3

Sensitivity and specificity of clinical and ultrasound variables for the prediction of RA

SensitivitySpecificityPositive LRNegative LRPPVNPVAUC
MCP joints
 MCP clinical involvement976930.0576950.828
 MCP clinical symmetry65.597190.3695740.810
 MCP GS ≥1 involvement1003820621000.690
 MCP GS ≥1 symmetry937640.0979920.845
 MCP GS ≥2 involvement904820.2163820.690
 MCP GS ≥2 symmetry867940.1781850.828
 MCP GS count ≥8451000.55100640.724
 MCP PD ≥1 involvement975520.0668940.759
 MCP PD ≥1 symmetry837940.2280820.810
 MCP PD ≥2 involvement906630.1672860.776
 MCP PD ≥2 symmetry838350.2183830.828
PIP joints
 PIP clinical involvement627630.5072670.690
 PIP clinical symmetry419360.6386610.672
 PIP GS ≥1 involvement796220.3368750.707
 PIP GS ≥1 symmetry487920.6570610.638
 PIP GS ≥2 involvement796620.3270760.724
 PIP GS ≥2 symmetry489050.5882630.690
 PIP PD ≥1 involvement766920.3571740.724
 PIP PD ≥1 symmetry459040.6281620.672
 PIP PD ≥2 involvement667630.4673690.707
 PIP PD ≥2 symmetry3897110.6492610.672
Wrist joints
 Wrist clinical involvement698650.3683740.776
 Wrist clinical symmetry489370.5688640.707
 Wrist GS ≥1 involvement974120.0862920.690
 Wrist GS ≥1 symmetry866220.2269820.741
 Wrist GS ≥2 involvement796930.3072770.741
 Wrist GS ≥2 symmetry529370.5288660.724
 Wrist PD ≥1 involvement934820.1464880.707
 Wrist PD ≥1 symmetry836620.2671790.741
 Wrist PD ≥2 involvement904820.2163820.690
 Wrist PD ≥2 symmetry697220.4371700.707
MTP joints
 MTP clinical involvement171000.83100550.586
 MTP clinical symmetry101000.90100530.552
 MTP GS ≥1 involvement695520.5661640.621
 MTP GS ≥1 symmetry557930.5673640.672
 MTP GS ≥2 involvement597220.5768640.655
 MTP GS ≥2 symmetry418320.7171560.621
 MTP PD ≥1 involvement529050.5483650.707
 MTP PD ≥1 symmetry351000.66100600.672
 MTP PD ≥2 involvement381000.62100620.690
 MTP PD ≥2 symmetry241000.76100570.621
Other variables
 Leiden score ≥8629390.4190710.776
 1987 ACR criteria (4/7 clinical)799080.2389810.845
 ACR criteria 4/7 GS9365.530.1073910.793
 ACR criteria 4/7 PD867640.1878850.810
 X-ray hand/foot erosion3.51000.97100450.517
 US hand/foot erosion38935.50.6785600.655
 ACPA positive481000.52100660.741
 ACPA positive or MTP PD ≥2 Involvement or MCP GS count ≥8761000.24100810.879
 PD10 index ≥10799311.50.2292820.862
  • ACPA, anti-cyclic citrullinated peptide antibody; ACR, American College of Rheumatology; AUC, area under the receiver operating characteristic curve; GS, ultrasound greyscale; LR, likelihood ratio; metacarpophalangeal joint (MCP) GS ≥1 involvement, MCP joint involvement with an ultrasound greyscale grade of at least 1; MCP joint GS count ≥8, at least eight MCP joints with GS involvement of grade ≥1; NPV, negative predictive value; PD, ultrasound power Doppler; PD10 index, summed power Doppler grades of MCP 2–3 joints, wrists and metatarsophalangeal (MTP) 2–3 joints; PIP, proximal interphalangeal joint; PPV, positive predictive value; RA, rheumatoid arthritis; US, ultrasound.