Table 2. Correlations between predictive ‘disease activity’ and ‘disease progression’ NMR indices (the Spearman-rank correlation coefficient ρ is given with the P value between brackets; n indicates the number of patients).
| Muscle group | n | ΔFat% (%) | Rmuscle_transf (year−1) | ΔcCSA (mm2) | ΔcCSArel (%) |
|---|---|---|---|---|---|
| Water T2 (ms) | |||||
| FIB (leg) | 6 | −0.37 (0.468) | −0.26 (0.623) | 0.77 (0.072) | 0.26 (0.623) |
| EXT (leg) | 6 | 0.54 (0.266) | 0.20 (0704) | −0.89 (0.019) | −0.66 (0.156) |
| TRIC (leg) | 6 | −0.37 (0.468) | −0.31 (0.544) | 0.09 (0.872) | 0.37 (0.468) |
| QUAD (thigh) | 10 | 0.79 (0.006) | 0.81 (0.005) | −0.55 (0.098) | −0.67 (0.033) |
| HSTR (thigh) | 10 | −0.27 (0.446) | −0.19 (0.603) | 0.58 (0.200) | −0.03 (0.934) |
| EXT (forearm) | 10 | 0.51 (0.130) | 0.53 (0.119) | −0.31 (0.379) | −0.44 (0.199) |
| FLEX (forearm) | 10 | 0.10 (0.783) | 0.10 (0.783) | −0.54 (0.109) | −0.38 (0.285) |
| pHw | |||||
| QUAD | 10 | 0.09 (0.803) | 0.10 (0.777) | −0.03 (0.934) | 0.01 (0.987) |
| HSTR | 6 | −0.03 (0.957) | 0.20 (0.704) | 0.09 (0.872) | −0.66 (0.156) |
| [Mg2+] (mM) | |||||
| QUAD | 10 | −0.18 (0.627) | −0.22 (0.533) | 0.71 (0.022) | 0.53 (0.117) |
| HSTR | 6 | −0.03 (0.957) | −0.31 (0.544) | −0.49 (0.329) | 0.37 (0.468) |
| PDE/γATP | |||||
| QUAD | 10 | −0.19 (0.603) | −0.25 (0.489) | 0.18 (0.627) | 0.30 (0.405) |
| HSTR | 6 | −0.37 (0.468) | −0.49 (0.329) | 0.54 (0.266) | 0.60 (0.208) |
| PME/γATP | |||||
| QUAD | 10 | 0.59 (0.074) | 0.60 (0.067) | −0.10 (0.777) | −0.24 (0.511) |
| HSTR | 6 | 0.31 (0.544) | 0.54 (0.266) | 0.09 (0.872) | −0.77 (0.072) |
| PCr/γATP | |||||
| QUAD | 10 | −0.58 (0.082) | −0.53 (0.117) | 0.73 (0.016) | 0.78 (0.008) |
| HSTR | 6 | −0.83 (0.042) | −0.88 (0.019) | 0.09 (0.872) | 0.60 (0.208) |
| Pi,tot/γATP | |||||
| QUAD | 10 | −0.02 (0.960) | 0.07 (0.855) | −0.19 (0.603) | −0.16 (0.651) |
| HSTR | 6 | −0.49 (0.329) | −0.20 (0.704) | 0.09 (0.872) | −0.09 (0.872) |
| Pi,tot/PCr | |||||
| QUAD | 10 | 0.43 (0.214) | 0.50 (0.138) | −0.65 (0.043) | −0.61 (0.060) |
| HSTR | 6 | −0.43 (0.397) | −0.09 (0.872) | −0.26 (0.623) | −0.49 (0.329) |
| Pi,b/Pi,tot | |||||
| QUAD | 10 | 0.22 (0.533) | 0.21 (0.556) | −0.14 (0.701) | −0.25 (0.489) |
| HSTR | 6 | −0.26 (0.623) | −0.43 (0.397) | −0.09 (0.872) | −0.03 (0.957) |
The water T2 value and the 31P NMR indices represent the average value of baseline and year 1 visits (the analysis with baseline water T2 values resulted in the same outcome for ρ and P values). ΔFat%, Fat% change between baseline and year-1 (in %); ΔcCSA, absolute change in contractile cross-sectional area change between baseline and year-1 (in mm2); ΔcCSArel, relative change in contractile cross-sectional area change between baseline and year-1 (in %); ATP, adenosine triphosphate; EXT, extensor; FIB, fibularis; FLEX, flexor; HSTR, hamstring; PDE, phosphodiesters; PCr, phosphocreatine; Pi,b, alkaline inorganic phosphate; Pi,tot, total inorganic phosphate; PME, phosphomonoesters; QUAD, quadriceps; [Mg2+], intramuscular magnesium concentration (in mM); pHw, weighted pH; Rmuscle_transf, muscle transformation rate (year−1). Significance levels: P<0.007 (NMRI) and P<0.02 (31P NMRS).