Linkage of Calprotectin with Inflammation, Activity and Treatment Response of Rheumatoid Arthritis: A Meta-Analysis

Figures & data

Figure 1. Study flow.

Via detailed search and screening, 38 articles were initially reviewed; after careful sorting, a total of 31 articles were included in this meta-analysis.

Figure 2. Pooled analysis of calprotectin levels between rheumatoid arthritis patients and healthy controls.

After a pooled analysis of 13 related articles, blood calprotectin levels were elevated in RA patients compared with HCs.

HC: Healthy control; RA: Rheumatoid arthritis.

Figure 3. Pooled analysis of the correlation between calprotectin levels and C-reactive protein in rheumatoid arthritis patients.

After a pooled analysis of 19 related articles, blood calprotectin level was positively related to CRP in RA patients.

CRP: C-reactive protein; RA: Rheumatoid arthritis.

Figure 4. Pooled analysis of the correlation between calprotectin levels and disease activity scores for 28 joints in rheumatoid arthritis patients.

After a pooled analysis of 17 related articles, blood calprotectin levels were positively correlated with DAS28 scores in RA patients.

DAS28: Disease Activity Score for 28 joints; RA: Rheumatoid arthritis.

Figure 5. Pooled analysis of calprotectin levels between rheumatoid arthritis responders and nonresponders.

After a pooled analysis of four related articles, blood calprotectin level was not different between responders and nonresponders.

Figure 6. Sensitivity analysis.

(A) Sensitivity analysis of calprotectin levels between rheumatoid arthritis patients and healthy controls. (B) Sensitivity analysis of the correlation between calprotectin levels and C-reactive protein. (C) Sensitivity analysis of the correlation between calprotectin levels and disease activity scores for 28 joints. (D) Sensitivity analysis of calprotectin level between RA responders and nonresponders.

RA: Rheumatoid arthritis.

Table 1. Publication bias in key assessments.

Items	Begg and Mazumdar test		Egger test
	Statistic (t)	p-value	Statistic (z)	p-value
Calprotectin between RA and HC	6.150	7.204 × 10^-5	1.342	0.179
Correlation of calprotectin with CRP	-0.035	0.972	-0.105	0.916
Correlation of calprotectin with DAS28	1.267	0.224	1.443	0.149
Calprotectin between responders and nonresponders	1.085	0.391	0.679	0.497

CRP: C-reactive protein; DAS28: Disease Activity Score for 28 joints; HC: Healthy control; RA: Rheumatoid arthritis.

Figure 7. Subgroup analyses.

(A) Separate analyses of the differences in serum or plasma calprotectin between rheumatoid arthritis patients and healthy controls. (B) Separate analyses of the correlation between serum or plasma calprotectin and C-reactive protein. (C) Disease activity scores for 28 joints. (D) Treatment response.