Plasma chitotriosidase activity versus CCL18 level for assessing type I Gaucher disease severity: protocol for a systematic review with meta-analysis of individual participant data

Table 1 Requested variables

Variable	Description
Gender	Male, female
Age at baseline	Year
Age at GD diagnosis	Year
Site of enrollment	Country
Acid beta-glucosidase genotype	–
Chitotriosidase genotype	Deficient[homozygous]; heterozygous; wild type
Previous history of enzyme replacement therapy at enrollment	Never treated with ERT, no ERT within the previous year, ERT within the previous year
Previous history of substrate reduction therapy at enrollment	Never treated with SRT, no SRT within the previous year, SRT within the previous year
Splenectomy	Yes, no
Time to FU visit	Month (0 for baseline)
Treatment received at FU	Placebo, untreated, imiglucerase, velaglucerase alpha, taliglucerase, miglustat, eliglustat, other
Plasma chitotriosidase activity at FU	nmol/mL/h
Serum CCL18 level at FU	ng/mL
Hemoglobin concentration at FU	g/dL
Platelet count at FU	10⁹/L
White blood cell count at FU	10⁹/L
Liver volume at FU	MN
Spleen volume at FU	MN
Previous history of bone event	Yes, no
Osteonecrosis (i.e., clinical history of bone crises with radiologic or magnetic resonance imaging confirmation) within the previous 12 months	Yes, no
Fracture with imaging confirmation within the previous 12 months	Yes, no
Skeletal site of fracture	Spine, hip, femur, knee, distal to the knee, shoulder, clavicle, humerus, elbow, distal to the elbow, rib, other

Abbreviations: GD Gaucher disease, ERT enzyme replacement therapy, FU follow-up; MN multiple of normal, SRT substrate reduction therapy