(488) ASPREO secondary analysis

A recent meta-analysis (4 trials) concluded that aspirin dose of 150-162 mg vs 75-81 mg initiated < 16 weeks gestational age (GA) decreased rates of preterm preeclampsia and preeclampsia with severe features (sPE). However, 3 of the 4 trials included were of low quality, and primary outcome was preeclampsia in only 1 of the trials. We conducted a secondary analysis of an RCT with primary outcome of sPE, and compared rates of sPE and preterm sPE between 162 vs 81 mg aspirin when initiated at < 16 weeks GA.

Study Design:

Secondary analysis of a RCT in high-risk obese gravidas comparing aspirin 162 (ASA 2) vs aspirin 81 mg (ASA 1) for preeclampsia prevention (ASPREO). Inclusion criteria were BMI >30 kg/m² and > 1 high risk factor: PE in prior pregnancy, at least stage I hypertension in the index pregnancy, diabetes. Exclusion criteria were: delivery < 20 weeks GA or delivery outcome data not available.  For this analysis we focused on those enrolled < 16 weeks GA. The primary outcome was: sPE. Secondary outcomes were: preterm sPE, total PE, abruption, postpartum hemorrhage, severe maternal morbidity. Relative risks with 95% CIs were reported.

Results:

A total of 107/209 (51%) were enrolled prior to 16 weeks GA (54 on ASA 2, 53 on ASA 1). Baseline characteristics were similar between groups (Table 1). There was no statistical difference in rates of sPE (28% vs 40%, RR: 0.7 (0.41-1.21)), or preterm sPE (13% vs 24%, 0.53 (0.23-1.22)) in those receiving ASA 2 vs ASA 1. Also, no differences were found in any of the analyzed secondary outcomes (Table 2).

Conclusion:

When comparing aspirin 162 mg vs 81 mg started prior to 16 weeks, we found a trend towards reduced rates of preeclampsia with severe features and preterm preeclampsia with severe features in those receiving the 162 mg dose, although this was not statistically significant. A large RCT is needed to address the optimal dose and timing of initiation of aspirin for preeclampsia prevention.