RESUMEN
Objective:To explore the value of octreotide suppression test(OST) in predicting the efficacy of somatostatin receptor ligands(SRLs) in the treatment of active acromegaly.Methods:The clinical data of 76 patients with active acromegaly from 2011 to 2020 was retrospectively analyzed. OST was carried out as follows: After an overnight fasting and baseline sampling of growth hormone(GH), 100 μg octreotide was subcutaneously injected, and sampling for GH was obtained every 2 hours for 8 hours. All patients were treated with SRLs for at least 3 months. A good GH response is defined as a post-treatment random GH<1 μg/L or >80% fall compared with the baseline GH. A good insulin-like growth factor Ⅰ(IGF-Ⅰ) response is defined as IGF-Ⅰ<1.3 upper limit of normal(ULN) or >50% reduction compared with the baseline. If both GH and IGF-Ⅰ fulfill the criteria of a good response, it is defined as a good GH and IGF-Ⅰ response.Results:The baseline level of GH during OST was 15.00(6.38, 34.20) μg/L, the median time to reach the nadir GH was(3.65±1.65) hours, and the nadir GH level was 1.47(0.50, 4.19) μg/L. The median GH suppression rate was 89.12%(72.71%, 95.09%). When the cutoff value of GH suppression rate in predicting a good GH response was 89.32%, the area under the curve(AUC) was 0.74, with a sensitivity of 81.80% and specificity of 66.00%. When the cutoff value of GH suppression rate in predicting a good IGF-Ⅰ response was 93.14%, the AUC was 0.64, with a sensitivity of 50.00% and specificity of 75.60%. When the GH suppression rate was 90.71%, the AUC was 0.78, with the sensitivity of 83.30% and specificity of 70.00% in predicting a good GH and IGF-Ⅰ response. Compared with GH/IGF-Ⅰ non-responders, GH/IGF-Ⅰ responders displayed lower nadir GH during OST, higher GH suppression rate and IGF-Ⅰ reduction rate, and lower ratio of IGF-1 to ULN( P<0.05). Conclusion:GH suppression rate during the OST is a valuable predictor to evaluate the efficacy of SRLs in patients with acromegaly, with the highest sensitivity and specificity when the cutoff value is 90.71%.