NTRK1 and rheumatoid arthritis: The highest values were found for trkA in the SpA group (trkA median in SpA 20 vs OA 4.7; P = 0.003; p75 median in SpA 13.4 vs OA 4.8; P = 0.03) and for p75 in the RA group (trkA median values: RA 16 vs OA 4.7; P = 0.004; p75 median values: RA25 vs OA 4.8; P = 0.01 as determined by the Mann Whitney U test).