3. Multivariate analysis of influencing factors of cervical
insufficiency
Presence or absence of CI (yes = 1, no = 2) was used as the dependent
variable, while significant and other relevant variables in univariate
analysis (age, gestation, parity, BMI, hypothyroidism, uterine fibroids,
pregnancy-induced hypertension, anemia, vaginitis, and hyperlipidemia)
were included in the logistic regression model, where α in = 0.05 and α
out = 0.1. After conducting a
multivariate adjustment for significant factors and possible confounders
on univariate analysis, the results demonstrated that patients with a
history of multiple pregnancies had a 17.51 times higher risk of CI than
negative patients(OR=17.51, 95%CI: 2.16-141.85, P=0.007); patients who
were pregnant by IVF-ET/ovulation induction were found to have a 3.26
times higher risk of CI than negative patients(OR=3.26, 95%CI:
1.69-6.30, P<0.001); patients with gestational
diabetes/pregnancy with diabetes were noted to have a 2.88 times higher
risk of CI than negative patients(OR=2.88, 95%CI:1.87-4.44,
P<0.001); patients with PCOS had an 8.72 times higher risk of
CI than negative patients(OR=8.72, 95%CI: 2.33- 32.64,P=0.001); and
patients with uterine malformations had a 4.00 times higher risk of CI
than negative patients(OR=4.00, 95%CI:1.07-14.97, P=0.040), as shown
in Table 3 . Notably, after adjusting for significant factors
and possible confounders in the univariate
analysis, the multivariate
analysis showed that BMI was not associated with the development of CI.
The prediction probability was
calculated using the model of logistic regression, in which a new
variable and multi-index combination was generated. The ROC curve
was then plotted (Figure 2).
The larger the area under the ROC
curve (AUC), the stronger the prediction ability of the index. The
results showed that the area under the ROC curve: multi-index
combination (0.728) > GDM or PGDM (0.614) >
IVF-ET/ovulation induction (0.586) > PCOS (0.539)
> previous multiple pregnancy (0.548) >
uterine malformation (0.510). Evidently,
the area under the curve following
the combination of multiple
indicators was 0.728, which was greater than 0.7, and was also
significantly greater than the area under the curve of a single
indicator, indicating that the model is fair. Accordingly, this once
again suggests that previous multiple pregnancy, IVF-ET/ovulation
induction conception, diabetes, uterine malformation, and PCOS are
related to the occurrence of CI, and the combination of multiple
indicators have a certain predictive ability for CI.
Discussion