Utility of Human Neutrophil Lipocalin as a Diagnosing Biomarker of Prosthetic Joint Infection: A Clinical Pilot Study

Figures & data

Table 1 Demographic Data for the Study Population

Characteristics	PJI (n=38)	Non-PJI (n=20)	p value
Age, years (mean ± SD)	66.4±6.7	67.3±8.2	0.43
Sex, n			0.00*
Male	24	11
Female	18	8
Body mass index, kg/m^2	26.9±3.6	27.9±2.8	0.56
Comorbidities, n (%)
Hypertension	16	9	0.00*
Diabetes	12	3	0.00*
Smoking	15	10	0.83
Alcoholism	12	4	0.01*
Joints, n			0.00*
Knee	33	18
Hip	5	2
Sinus tract, n	5	0	0.003*
Laboratory findings
ESR (mm/H, mean ± SD)	41.63±19.26	14.20±7.12	0.000*
CRP (mg/L, mean ± SD)	22.27±19.6	15.99±13.1	0.204
D-dimer (mg/L, mean ± SD)	1.59±0.9	1.41±0.5	0.414
PCT (ng/mL, mean ± SD)	0.39±0.1	0.20±0.1	0.000*
HNL (ng/mL, mean ± SD)	199.01±94.3	64.81±42.4	0.000*

Notes: *P<0.05.

Abbreviations: ESR, erythrocyte sedimentation rate; CRP, C reactive protein; PCT, procalcitonin; HNL, human neutrophil lipocalin.

Figure 1 Flowchart of patient inclusion.

Table 2 Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value, and Accuracy of Inflammatory Markers

	Sensitivity	Specificity	PPV	NPV	PLR	NLR	AUC (95% CI)	Cutoff value	P value
HNL	81.6% (71.0–93.0%)	85.0% (74.6–96.9%)	91.2% (88.1–98.7%)	70.8% (66.5–80.2%)	3.438 (1.895–4.606)	0.216 (0.109–0.330)	0.919 (0.851–0.987)	105.1 ng/mL	0.000
CRP	57.9% (43.5–67.1%)	80.0% (71.1–89.7%)	84.6% (76.1–92.3%)	50.0% (41.7–60.2%)	2.894 (1.156–4.246)	0.526 (0.353–0.783)	0.531 (0.429–0.719)	19.2 mg/L	0.204
ESR	76.3% (62.3–82.2%)	93.5% (88.5–100%)	93.5% (84.3–98.9%)	66.7% (54.3–77.7%)	3.632 (2.025–4.759)	0.263 (0.147–0.471)	0.878 (0.773–0.982)	24.5 mm/H	0.001
PCT	78.9% (65.7–85.8%)	90.0% (85.4–99.1%)	93.8% (83.9–99.7%)	69.2% (60.2–79.7%)	5.894 (4.098–9.701)	0.233 (0.125–0.437)	0.856 (0.678–0.913)	0.32 mg/L	0.001
D-dimer	31.6% (21.8–40.7%)	100% (95.0–100%)	100.0% (95.0–100%)	43.5% (31.1–50.5%)	+∞	0.284 (0.151–0.384)	0.579 (0.384–0.678)	2.13 mg/L	0.417

Abbreviations: ESR, erythrocyte sedimentation rate; CRP, C reactive protein; PCT, procalcitonin; HNL, human neutrophil lipocalin; AUC, area under the curve; PPV, positive predictive value; NPV, negative predictive value; PLR, positive likelihood ratio; NLR, negative likelihood ratio.

Figure 2 Comparison of different serum biomarkers levels between PJI group and non-PJI group. (A). There was not significantly different of D-dimer value between PJI group and non-PJI group (P = 0.414) (B). There was not significantly different of CRP value between PJI group and non-PJI group (P = 0.204) (C). There was significantly different of HNL level between PJI group and non-PJI group (P = 0.000) (D). The PCT value of the PJI group was significantly higher than that of the non-PCT group (P = 0.000) (E). There was significantly different of ESR level between PJI group and non-PJI group (P = 0.000).

Figure 3 ROC curves for diagnostic indicators with an AUC >0.7, which included PCT, ESR, HNL.