Abstract
BACKGROUND AND AIMS: Sickle cell disease is a genetic disorder whose pathophysiology is primarily characterized by vasoocclusive crises and hemolytic crises. The stationary phase describes the interval between two vasoocclusive crises. The aim of this systematic review and meta-analysis was to synthesize studies published over the past two decades on the complete blood count profile in patients with sickle cell disease in the steady state, and to emphasize the need for prospective studies to better characterize hematological profiles and establish potential reference values specific to this patient population. The goal was to provide a consolidated and contextual overview of the available evidence for this patient population. METHODS: The search period for the included studies spanned from 2000 to 2025. This systematic review and meta-analysis was conducted following PRISMA guidelines. The included studies were descriptive cross-sectional designs. Articles were retrieved from PubMed, Embase, Google Scholar, and Web of Science, with a total of 21 studies analyzed. Data were extracted and analyzed using R version 4.3.2, applying a random effects model for means and confidence intervals. The JBI Critical Appraisal Checklist was used to assess the risk of bias. Forest plots were employed to present overall and individual study effect sizes with 95% confidence intervals, and statistical significance was set at p < 0.05. RESULTS: The risk of bias across these domains was low to moderate, and no study was excluded based on the quality assessment. The mean red blood cell count, estimated using a random effects model, was 3.42 T/L [2.83; 4.13], ranging from 2.54 T/L [2.33; 2.77] to 11.40 T/L [10.21; 12.73]. The mean hemoglobin was 8.83 g/dL [8.29; 9.41], with values ranging from 7.51 g/dL [7.32; 7.71] to 11.62 g/dL [11.29; 11.96]. The mean leukocyte count was 10.87 G/L [9.47; 12.49], with a range from 7.10 G/L [6.43; 7.84] to 15.64 G/L [13.72; 17.83]. The mean platelet count was 332.07 G/L [285.32; 386.48], ranging from 121.44 G/L [120.44; 122.44] to 450.00 G/L [446.55; 453.48]. CONCLUSION: The overall results from the analyses indicate consistent differences in hematological parameters compared to the reference values established by professional societies. These findings underscore the importance of conducting prospective studies to better characterize hematological profiles and to explore potential reference values specific to patients with sickle cell disease in the steady state.