BackgroundSpinal anesthesia (SA) is widely used for anesthetic management of patients undergoing hip surgery, and hypotension is the most common cardiovascular side effect of SA. This paper aims to assess the lowest effective dose of SA that reduces the occurrence of intraoperative hypotension in elderly patients scheduled for major lower limb orthopedic surgery.MethodsWe conducted a systematic review of randomized controlled trials (RCTs) performed in elderly patients scheduled for surgical hip repair and a meta-analysis with meta-regression on the occurrence of hypotensive episodes at different effective doses of anesthetics. We searched PUBMED®, EMBASE®, and the Cochrane Controlled Clinical trials registered.ResultsOur search retrieved 2085 titles, and after screening, 6 were finally included in both the qualitative and quantitative analysis, including 344 patients [15% (10–28) males], with a median (25th to 75th interquartile) age of 82 (80–85). The risk of bias assessment reported “low risk” for 5 (83.3%) and “some concerns” for 1 (16.7%) of the included RCTs.The low dose of SA of [mean 6.5 mg (1.9)] anesthetic was associated with a lower incidence of hypotension [OR = 0.09 (95%CI 0.04–0.21);p= 0.04;I2= 56.9%], as compared to the high-dose of anesthetic [mean 10.5 mg (2.4)].ConclusionsIn the included studies of this meta-analysis, a mean dose of 6.5 mg of SA was effective in producing intraoperative comfort and motor block and associated with a lower incidence of hypotension as compared to a mean dose of 10.5 mg.Trial registrationCRD42020193627Supplementary InformationThe online version contains supplementary material available at 10.1186/s44158-022-00047-6.