The role of serum apelin in retinopathy of prematurity

Figures & data

Table 1 Demographic characteristics of studied groups

Variables	ROP group (n=38)	Non-ROP (n=27)	Test of significance	P-value
Gender, n (%)				1.000
Female	18 (47.4)	11 (40.8)	χ^2=0.000
Male	20 (52.6)	16 (59.2)
Gestational age (weeks)				0.467
X ± SD	30.37±1.29	31.14±1.33	t=0.534
Range	28–32	28–32
Birth weight (kg)				0.197
X ± SD	1.42±0.54	1.58±0.48	t=1.696
Range	987–1,205	1,015–1,227

Notes: t= Student’s t-test, χ²= chi-square test, P>0.05: nonsignificant.

Abbreviations: X ± SD, mean ± standard deviation; ROP, retinopathy of prematurity.

Table 2 Correlation between ROP and some risk factors among patients group

Variables	Stages of ROP (n=38)			χ^2	P-value
	I (n=4)	II (n=8)	III–V (n=26)
Apgar score (at 5 min)					<0.001 (HS)
4–6 (n=3)	0 (0.0%)	0 (0.0%)	3 (100%)	25.430
7–10 (n=32)	23 (71.9%)	8 (25%)	1 (3.1%)
Mode of delivery					0.144 (NS)
CS (n=25)	14 (56%)	7 (28%)	4 (16%)	3.869
Vaginal (n=10)	9 (90%)	1 (10%)	0 (0.0%)
PROM					0.102 (NS)
Negative (n=28)	16 (57%)	8 (29%)	4 (14%)	4.565
Positive (n=7)	7 (100%)	0 (0.0%)	0 (0.0%)
O2 therapy					0.039 (S)
<7 days (n=3)	3 (100%)	0 (0.0%)	0 (0.0%)	5.902
>7 days (n=32)	20 (62.5%)	8 (25%)	4 (12.5%)
MV					0.425 (NS)
Negative (n=20)	16 (80%)	4 (20%)	0 (0.0%)
Positive (n=15)	7 (47%)	4 (26.5%)	4 (26.5%)	1.712
Pneumothorax					0.374 (NS)
Negative (n=26)	17 (65%)	7 (27%)	2 (8%)	1.968
Positive (n=9)	6 (67%)	1 (11%)	2 (22%)		0.252 (NS)
Sepsis
Negative (n=13)	10 (77%)	3 (23%)	0 (0.0%)	2.759
Positive (n=22)	13 (59%)	5 (23%)	4 (18%)
Blood transfusion					0.977 (NS)
Negative (n=27)	18 (67%)	6 (22%)	3 (11%)
Positive (n=8)	5 (62.5%)	2 (25%)	1 (12.5%)	0.048
Neonatal jaundice					0.558 (NS)
Negative (n=28)	18 (64%)	6 (21%)	4 (15%)	1.168
Positive (n=7)	5 (71%)	2 (29%)	0 (0.0%)
Perinatal asphyxia					0.192 (NS)
Negative (n=34)	23	8	3	4.978
Positive (n=1)	0	0	1

Notes: χ²= chi-square test, P<0.05: significant, P>0.05: nonsignificant, P<0.001: highly significant.

Abbreviations: ROP, retinopathy of prematurity; CS, c-section; PROM, premature rupture of membranes; MV, mechanical ventilation; S, significant; NS, nonsignificant; HS, highly significant; min, minutes.

Table 3 Serum apelin levels at birth and 4–6 weeks among the studied groups

Serum apelin levels	ROP group	Non-ROP group	t	P-value
Serum apelin at birth (ng/mL)				0.313
Range	1.4–2.4	2–2.6	1.032
X ± SD	1.5±0.6	1.8±0.4
Apelin at 4–6 weeks (ng/m L)				0.024*
Range	1.6–2.7	2.5–3.9	5.312
X ± SD	1.7±0.8	2.9±0.4

Notes:

* P<0.05: significant difference t= Student’s t-test. A comparison of mean levels of serum apelin between the groups of patients and controls was undertaken. At the sampling time at birth, there were no significant differences between respective mean values in the two groups (P>0.05). Measurements made at 4–6 weeks after birth showed higher mean concentrations of serum apelin in patients (P<0.05).

Abbreviations: ROP, retinopathy of prema turity; X ± SD, mean ± standard deviation.

Figure 1 ROC curve between patients and control groups as regards serum apelin levels at birth.

Abbreviation: ROC, receiver operating characteristic.

Figure 2 Interactive dot diagram between patients and control groups as regards serum apelin levels at birth.

Notes: The best cutoff value was 2.18 ng/mL, with a sensitivity of 42.9% and a specificity of 80%. 1= patients; 0= control.

Figure 3 ROC curve between patients and control groups as regards serum apelin levels, at 4–6 weeks of age.

Abbreviation: ROC, receiver operating characteristic.

Figure 4 Interactive dot diagram between patients and control groups as regards serum apelin at 4–6 weeks of age.

Notes: The best cutoff value was 2.7 ng/mL, with a sensitivity of 62.9% and a specificity of 80%. 1= ROP; 0= non-ROP.
Abbreviation: ROP, retinopathy of prematurity.