ObjectiveTo systematically evaluate the effect of high-flow nasal cannula in immunocompromised patients with acute respiratory failure.MethodsRandomized controlled trials (RCT) or cohort studies on the efficacy of high-flow oxygen therapy in immunocompromised patients with acute respiratory failure were reviewed by computer in PubMed, EMBASE, Cochrane Library, and China Knowledge Network, Wanfang and VIP databases. The group used HFNC and the control group used a mask or a nasal catheter to give oxygen-based conventional oxygen therapy (COT) or noninvasive ventilation (NIV). Two investigators conducted quality assessments and data extractions based on the Cochrane Collaboration Risk Assessment Manual and the Newcastle-Ottawa Scale. Meta analysis was performed using RevMan 5.3 software. The main outcome measures included tracheal intubation rate, and intensive care unit (ICU) mortality. The secondary outcomes included ICU hospitalization time.ResultsThe study included 13 articles (4 RCTs, 9 cohort studies), a total of 1133 subjects, with 583 in the HFNC group and 550 in the control group (280 in the COT and 270 in the NIV). Meta-analysis showed that HFNC was significantly different from COT in reducing tracheal intubation rate in immunocompromised patients with respiratory failure (OR=0.49, 95%CI 0.33 - 0.72, P=0.0003), but no statistical significance compared with NIV (OR=0.73, 95%CI 0.52 - 1.02, P=0.07); two-combination analysis showed that HFNC had a significant advantage in reducing tracheal intubation rate compared with COT/NIV (combined OR=0.61, 95%CI 0.47 - 0.79, P=0.0002). In terms of ICU mortality, there was a statistically significant difference between HFNC and COT (OR=0.59, 95%CI 0.35 - 1.01, P=0.05) or NIV (OR=0.63, 95%CI 0.44 - 0.91, P=0.01). The results of the two subcombinations and analysis did not change (combined OR=0.62, 95%CI 0.46 - 0.83, P=0.002). In terms of ICU hospital stay, there was no statistically significant difference between HFNC and COT (MD=−4.52, 95%CI −9.43 - 0.39, P=0.07), but the difference was statistically significant compared with NIV (MD=−1.46, 95%CI −2.41 - −0.51, P =0.003); the two sub-combinations and analysis results showed significant difference (combined MD=−3.41, 95%CI −6.16 - −0.66, P=0.01). According to different research types, after subgroup analysis, the analysis results were not different from the combined results. Sensitivity analysis revealed that HFNC could significantly reduce the patient's ICU hospital stay compared with the control group oxygen therapy. The results of the funnel chart analysis show that there were publication offsets in the studies on tracheal intubation rate and ICU mortality included in the literature; studies on ICU hospital stays had a smaller publication offset.ConclusionsCompared with COT, HFNC can reduce the tracheal intubation rate of patients, but there is no significant difference compared with NIV; HFNC can reduce the ICU mortality of patients compared with COT/NIV. However, due to the high heterogeneity between the studies, whether HFNC can reduce ICU hospital stay remains to be further explored.