Aerobic capacity and disease activity in children, adolescents and young adults with juvenile idiopathic arthritis (JIA)

Table 3 Median (IQR) Standard Laboratory Values and Spearman’s Correlation Coefficients for Aerobic Capacity (expressed by absolute and relative VO2 peak) (level of significance:* indicates significance < 0.05; ** indicates significance <0.01)

	Median (IQR)	Correlation with Z-score VO_2peak(p -value)	Correlation Z-score VO_2peak/kg (p -value)
ESR (mm)	8.0 (13)	−0.3 (*)	−0.5 (**)
CRP (mg/l)	5.5 (6)	−0.2	−0.2
Thrombocytes (10.9/l)	302 (110)	−0.4 (**)	−0.5(**)
Haemoglobin (mmol/l) boys	8.1 (1.2)	+0.0	+0.5 (*)
Haemoglobin (mmol/l) girls	7.8 (1.1)	+0.3 (*)	+0.2

Abbreviations
IQR: Interquartile Range; Z-score_: standard deviation of the individual patient compared with values from age- and sex- related historical Dutch controls(37); VO_{2peak abs}: highest oxygen uptake in liters of oxygen per minute (l/min) during maximum exercise test in l/min; VO_2peak/kg_l : highest oxygen uptake in milliliters of oxygen per kilogram of bodyweight per minute (ml/min/kg) during maximum exercise; ESR: Erythrocyte Sedimentation Rate (ref 2-12 mm in 1 hour); CRP: C-Reactive Protein (ref 0–10 milligram per litre); thrombocytes (ref 150–450 10.9 per litre); Haemoglobin boys (ref: age group 10-12 yrs: 6.6-.8.4 millimol per liter age 12–18 yrs 6.9-9.1 millimol per liter; age >18 yrs: 8.6-10.5 millimol per liter); Hemoglobin girls (ref: age 10–12 yrs 6.6-8.4 millimol per liter; age 12–18 yrs 6.8-8.3 millimol per liter; age >18 yrs:7.5-9.5 millimol per liter).

ISSN: 1546-0096