Objectives: To assess the accuracy of the placental alpha microglobulin-1 (PAMG-1) to predict preterm birth (PB) in women with symptoms of PB through use of formal methods for systematic reviews and meta-analytic techniques.
Methods: We performed a comprehensive search of medical bibliographic databases to identify observational studies that reported on the predictive accuracy of PAMG-1 for PB. Two investigators independently assessed studies, assessed quality of studies, and extracted data. Summary receiver operating characteristic (SROC) curves, pooled sensitivities, specificities, likelihood ratios (LR), and diagnostic odds ratio (DOR) were generated.
Results: Seventeen studies involving 2590 women met the inclusion criteria. Meta-analysis of 15 studies (including 1906 women) revealed a pooled sensitivity of 66.2% (95% CI: 59.1, 72.7) and specificity of 96.1% (95% CI: 95.1, 97.0) with the SROC equal to 0.97 (95% CI: 0.95, 0.98) for prediction of delivery within 7 d of testing. The summary estimates were 15.26 (95% CI: 11.80, 19.75) for LR + and 0.31 (95% CI: 0.17, 0.55) for LR - for prediction of delivery within 7 d of testing. Pooled estimate of DOR for predicting delivery within 7 d of testing was 55.13 (95% CI: 35.32, 86.06). The sensitivity, specificity and the SROC of PAMG-1 pooled from 10 studies (including 1508 women) for prediction of delivery within 14 d of testing were 64.4% (95% CI: 56.8, 71.5), 96.9% (95% CI: 95.8, 97.7) and 0.97 (95% CI: 0.95, 0.98). The overall pooled LR + and LR - of PAMG-1 for predicting delivery within 14 d of testing among the included studies were 16.72 (95% CI: 12.03, 23.23) and 0.42.1 (95% CI: 0.31, 0.56), respectively. The pooled DOR of the PAMG-1 for prediction delivery within 14 d of testing was equal to 44.65 (95% CI: 26.30, 75.78).
Conclusion: Cervical PAMG-1 had a high accuracy to predict PB within 7 and 14 d of testing in symptomatic pregnant women.
Keywords: Biomarker; placental alpha macroglobulin-1; predictive value; prematurity; preterm labor.