Agreement between two scales used for assessing risk classification for thromboembolic events and the requirement of postpartum pharmacological prophylaxis

Objectives: To determine agreement in assessing the need for postpartum pharmacological prophylaxis between the scale of the Royal College of Obstetricians and Gynaecologists and the Colombian guideline scale in a Level IV institution in Bogota, Colombia.

Material and methods: Diagnostic agreement study assembled on a cross-sectional study. The included population consisted of pregnant women with 24 or more weeks of pregnancy admitted between March 1 and April 30 of 2021 to a high complexity private institution in Bogotá, Colombia, for labor induction, in active labor, for elective cesarean section, or who required urgent cesarean section. Convenience sampling was used. Measured variables included demographics, risk factors, risk classification and pharmacological prophylaxis according to the two scales. The prevalence of risk factors for each scale was estimated and agreement regarding prophylaxis indication between the two scales was measured using the weighted kappa value.

Results: Overall, 320 patients were included. According to the scale of the Royal College Obstetricians and Gynaecologists, 54.7 % patients were classified as low risk, 42.5 % as intermediate risk and 2.8 % as high risk. The Colombian scale classified 80 % of patients as low risk, 17.2 % as intermediate risk, 2.2 % as high risk, and 0.6 % as very high risk. The weighted kappa value for agreement regarding the indication was 0.47 (95 % CI: 0.38-0.56).

Conclusions: Agreement between the two scales to determine the need for postpartum pharmacological prophylaxis is moderate. Risk classification criteria for the Colombian scale should be validated in a second cohort. Moreover, the predictive ability of the Colombian guideline tool should be assessed at different cut-off points in terms of the consequences of false positive and false negative results.