BACKGROUND: In transgender individuals assigned female at birth, testosterone therapy is employed for body masculinization. Guidelines recommend close monitoring for potential side effects of hormonal therapy, especially during the first year. Erythrocytosis is a common finding during testosterone therapy and has been associated with a potential risk of thrombotic and cardiovascular events. Currently, the hematologic effects of testosterone therapy are understudied, with existing data primarily derived from the cisgender male population. The aim of this study was to comprehensively examine the hematological changes induced by testosterone therapy in the transgender population.
METHODS: A systematic search was conducted using the electronic database PubMed.
RESULTS: Thirty-six manuscripts were retrieved. After screening for original studies, 19 articles were included. Selected articles were published between 2005 and 2023.
CONCLUSIONS: In our systematic review, the prevalence of erythrocytosis varied from 0% to 29.3%, with severe erythrocytosis ranging from 0.5% to 2.3%. Testosterone therapy was associated with an increase in hemoglobin and hematocrit, particularly within the first year of therapy. Factors such as serum testosterone levels, along with the duration, doses, and formulation of testosterone therapy, were found to be associated with the development of erythrocytosis. Further research is crucial to provide specific recommendations for clinical practice.

BACKGROUND: Approximately, 11% of trans men experience erythrocytosis diagnosis due to testosterone administration during the first year of the gender-affirming hormone treatment (GAHT).
OBJECTIVE: To identify and compare the effect of different testosterone formulations on hematocrit (Hct) and diagnose erythrocytosis in trans men.
METHODS: This systematic review was based on PRISMA guidelines. We performed an electronic search of PubMed, Embase, and Web of Science in January 2024. The Newcastle-Ottawa scale was used to evaluate the quality of evidence in the observational studies.
RESULTS: Of the 152 records retrieved, 18 met the eligibility criteria. Studies observed an increase of up to 5% in Hct in trans men using injectable testosterone undecanoate (TU), and up to 6.9% in trans men using intermediate injectable testosterone esters (TE). Trans men using TE experience a larger increase in serum Hct levels compared to those receiving TU. Erythrocytosis prevalence varies according to the cutoff used (50%, 52%, and 54%). Erythrocytosis was also associated with tobacco use, age at initiation of hormone therapy, body mass index (BMI), and pulmonary conditions. Studies that evaluated the effect of testosterone formulation on erythrocytosis diagnosis present conflicting result. Trans men have a hazard ratio of 7.4 (95% CI: 4.1, 13.4) of developing erythrocytosis compared to cisgender men, using a 52% hematocrit cutoff.
CONCLUSIONS: All testosterone formulations result in an increase in Hct, irrespective of dose, formulation, and administration method. Smoking, higher age at initiation of the testosterone therapy, higher BMI, and a predisposing medical history are associated with this increase in Hct. The difference in effect of TE and TU on Hct is conflicting, although it is important to point out that these data come from observational studies, retrospective, and with a small-sample size.

UNASSIGNED: This study aimed to systematically analyze the existing literature and conduct a meta-analysis on the acute effects of apnea on the hematological response by assessing changes in hemoglobin (Hb) concentration and hematocrit (Hct) values.
UNASSIGNED: Searches in Pubmed, The Cochrane Library, and Web of Science were carried out for studies in which the main intervention was voluntary hypoventilation, and Hb and Hct values were measured. Risk of bias and quality assessments were performed.
UNASSIGNED: Nine studies with data from 160 participants were included, involving both subjects experienced in breath-hold sports and physically active subjects unrelated to breath-holding activities. The GRADE scale showed a \"high\" confidence for Hb concentration, with a mean absolute effect of 0.57 g/dL over control interventions. \"Moderate\" confidence appeared for Hct, where the mean absolute effect was 2.45% higher over control interventions. Hb concentration increased to a greater extent in the apnea group compared to the control group (MD = 0.57 g/dL [95% CI 0.28, 0.86], Z = 3.81, p = 0.0001) as occurred with Hct (MD = 2.45% [95% CI 0.98, 3.93], Z = 3.26, p = 0.001).
UNASSIGNED: Apnea bouts lead to a significant increase in the concentration of Hb and Hct with a high and moderate quality of evidence, respectively. Further trials on apnea and its application to different settings are needed.

OBJECTIVE: This study aimed to illustrate the effect of malaria infection on red blood cell parameters in children and evaluate the diagnostic relevance of haematological parameters in predicting malaria.
METHODS: The studies were identified through databases like PubMed, Google Scholar, and Scopus to retrieve related articles. Fourteen studies were selected by literature search based on inclusion and exclusion criteria, and a meta-analysis on different red blood cell parameters was performed.
RESULTS: Haematocrit, haemoglobin concentration, and RBC count show statistically significant findings with p values of (<0.00001), (p<0.00001) and (p=0.0004), respectively. Other parameters like MCV, MCH, and MCHC show statistically non-significant results with p values of 0.21, 0.36, and 0.63, respectively.
CONCLUSIONS: Considering the above findings, the combination of haemoglobin concentration, haematocrit, and RBC counts could be used as reliable parameters to predict the presence of infection and included in the diagnostic strategy for malaria in children.

We compare the hematocrit, hemoglobin, need for transfusion, recurrent phototherapy, serum bilirubin level, and serum ferritin at different time frames for the umbilical cord milking (UCM) and delayed cord clamping (DCC) in both full-term and preterm infants. A comprehensive search through various databases aimed to compare UCM and DCC studies until May 2nd, 2023. Cochrane and NIH tools assessed RCTs and cohorts, respectively. Meta-analysis employed Review Manager 5.4 software, calculating MD and RR with 95% CIs for continuous and dichotomous data. We included 20 studies with a total of 5189 infants. Regarding preterm infants, hematocrit level showed no significant difference between intact Umbilical Cord Milking (iUCM) compared to DCC (MD = -0.24, 95% CI [-1.11, 0.64]). Moreover, Neonatal death incidence was significantly higher with the UCM technique in comparison to DCC (RR = 1.28, 95% CI [1.01 to 1.62]). Regarding term and late preterm infants, Hematocrit level showed no significant difference between the iUCM or cUCM techniques compared to DCC (MD = 0.21, 95% CI [-1.28 to 1.69]), (MD = 0.96, 95% CI [-1.02 to 2.95]), respectively. UCM led to a higher risk of neonatal death in preterm infants compared to DCC. However, the incidence of polycythemia was lower in the UCM group. Additionally, UCM was associated with higher rates of severe IVH events. Based on these findings, DCC may be preferred due to its lower incidence of severe IVH and neonatal death.
Nous comparons l\'hématocrite, l\'hémoglobine, le besoin de transfusion, la photothérapie récurrente, le taux de bilirubine sérique et la ferritine sérique à différentes périodes pour la traite du cordon ombilical (UCM) et le clampage retardé du cordon (DCC) chez les nourrissons nés à terme et prématurés. Une recherche complète dans diverses bases de données visait à comparer les études UCM et DCC jusqu\'au 2 mai 2023. Les outils Cochrane et NIH ont évalué les ECR et les cohortes, respectivement. La méta-analyse a utilisé le logiciel Review Manager 5.4, calculant le MD et le RR avec des IC à 95 % pour les données continues et dichotomiques. Nous avons inclus 20 études portant sur un total de 5 189 nourrissons. Concernant les nourrissons prématurés, le niveau d\'hématocrite n\'a montré aucune différence significative entre la traite du cordon ombilical intact (iUCM) et la DCC (DM = -0,24, IC à 95 % [-1,11, 0,64]). De plus, l\'incidence des décès néonatals était significativement plus élevée avec la technique UCM qu\'avec la technique DCC (RR = 1,28, IC à 95 % [1,01 à 1,62]). Concernant les nourrissons à terme et peu prématurés, le niveau = 0,21, IC à 95 % [-1,28 à 1,69]), (DM = 0,96, IC à 95 % [-1,02 à 2,95]), respectivement. L\'UCM a entraîné un risque plus élevé de décès néonatal chez les nourrissons prématurés par rapport au DCC. Cependant, l\'incidence de la polyglobulie était plus faible dans le groupe UCM. De plus, l’UCM était associée à des taux plus élevés d’événements IVH graves. Sur la base de ces résultats, le DCC peut être préféré en raison de sa plus faible incidence d\'IVH grave et de décès néonatals. d\'hématocrite n\'a montré aucune différence significative entre les techniques iUCM ou cUCM par rapport à la technique DCC (DM.

OBJECTIVE: Dried blood spot (DBS) is one of promising home sampling methods for therapeutic drug monitoring (TDM). However, the associated reliability and feasibility (including yield, adherence, and preference), which are criteria for the promotion of home-based DBS, remain unknown. This systematic review and meta-analysis aimed to evaluate the reliability and feasibility of TDM using DBS sampling.
METHODS: In this study, a combination of MeSH and free terms for (dried blood spot*[title/abstract])AND (\"Drug Monitoring\"[Mesh])AND(home OR venous)was surveyed using EMBASE, PubMed, Cochrane Library, and Web of Science upon gathering published. we registered this study protocol with the International Prospective Registry of Systematic Reviews (CRD42021247559).
RESULTS: Approximately half (35/75) of the evaluations reported good agreement between DBS and plasma, and the results for drugs with poor agreement may be improved using a haematocrit-based physiological equation. The yield and adherence to home-based DBS exceeded 87%, and questionnaire-based preference for DBS was 77%.
CONCLUSIONS: DBS may be a reliable and feasible home sampling method; however, it requires intricate design and evaluation before implementation.

Rapid fluid administration may decrease hemoglobin concentration (Hb) by a diluting effect, which could limit the increase in oxygen delivery (DO2) expected with a positive response to fluid challenge in critically ill patients. Our aim was to quantify the decrease in Hb after rapid fluid administration.
Our protocol was registered in PROSPERO (CRD42020165146). We searched PubMed, the Cochrane Database, and Embase from inception until February 15, 2022. We selected studies that reported Hb before and after rapid fluid administration (bolus fluid given over less than 120 min) with crystalloids and/or colloids in adults. Exclusion criteria were studies that included bleeding patients, or used transfusions or extracorporeal circulation procedures. Studies were divided according to whether they involved non-acutely ill or acutely ill (surgical/trauma, sepsis, circulatory shock or severe hypovolemia, and mixed conditions) subjects. The mean Hb difference and, where reported, the DO2 difference before and after fluid administration were extracted. Meta-analyses were conducted to assess differences in Hb before and after rapid fluid administration in all subjects and across subgroups. Random-effect models, meta-regressions and subgroup analyses were performed for meta-analyses. Risk of bias was assessed using the Cochrane Risk of Bias Assessment Tool. Inconsistency among trial results was assessed using the I2 statistic.
Sixty-five studies met our inclusion criteria (40 in non-acutely ill and 25 in acutely ill subjects), with a total of 2794 participants. Risk of bias was assessed as \"low\" for randomized controlled trials (RCTs) and \'low to moderate\' for non-RCTs. Across 63 studies suitable for meta-analysis, the Hb decreased significantly by a mean of 1.33 g/dL [95% CI - 1.45 to - 1.12; p < 0.001; I2 = 96.88] after fluid administration: in non-acutely ill subjects, the mean decrease was 1.56 g/dL [95% CI - 1.69 to - 1.42; p < 0.001; I2 = 96.71] and in acutely ill patients 0.84 g/dL [95% CI - 1.03 to - 0.64; p = 0.033; I2 = 92.91]. The decrease in Hb was less marked in patients with sepsis than in other acutely ill patients. The DO2 decreased significantly in fluid non-responders with a significant decrease in Hb.
Hb decreased consistently after rapid fluid administration with moderate certainty of evidence. This effect may limit the positive effects of fluid challenges on DO2 and thus on tissue oxygenation.

UNASSIGNED: The aim of this systematic review and meta-analysis was to investigate the association between obstructive sleep apnea (OSA) and erythrocytosis.
UNASSIGNED: The PubMed, Web of Science, and Cochrane Library databases were searched for articles examining hematocrit values in patients with OSA and control individuals published till September 1, 2021. The pooled standardized mean difference (SMD) with 95% confidence interval (CI) was calculated, and subgroup analyses were performed.
UNASSIGNED: Eleven eligible studies with a total of 4608 patients with OSA were included in this meta-analysis. Pooled outcomes revealed that hematocrit values were significantly higher in patients with OSA than in controls (SMD, 0.19; 95% CI, 0.08-0.29; p < .01). When studies were stratified by disease severity, the significant differences in hematocrit values between patients and controls were only observed in the severe OSA group (SMD, 0.34; 95% CI, 0.08-0.59; p < .01), but not in the mild and moderate OSA groups. In subgroup analyses according to sex and publication year, significant differences in hematocrit values between patients and controls remained stable in studies with only female patients (SMD, 0.25; 95% CI, 0.12-0.38; p < .01) and in studies published after 2012 (SMD, 0.17; 95% CI, 0.06-0.28, p < .01).
UNASSIGNED: Our meta-analysis revealed that the hematocrit value was significantly increased in patients with OSA, particularly in severe patients, compared with that in controls. However, the elevation was modest, and the hematocrit value is expected to be within the normal range in patients with OSA. These data suggest that OSA leads to slight increases in hematocrit but does not cause clinically significant erythrocytosis.

OBJECTIVE: We sought to compare testosterone formulations and determine the degree that hematocrit increases vary by testosterone therapy formulation. As head-to-head trials are rare, network meta-analysis of the contemporary studies is the only way to compare hematocrit changes by testosterone type, including topical gels and patches, injectables (both short-acting and long-acting) and oral tablets.
METHODS: We conducted a thorough search of listed publications in Scopus®, PubMed®, Embase®, Cochrane CENTRAL, and ClinicalTrials.gov. A total of 29 placebo-controlled randomized trials (3,393 men) met inclusion criteria for analysis of mean hematocrit change after testosterone therapy. Randomized controlled trial data for the following formulations of testosterone were pooled via network meta-analysis: gel, patch, oral testosterone undecanoate, intramuscular testosterone undecanoate, and intramuscular testosterone enanthate/cypionate.
RESULTS: All types of testosterone therapies result in statistically significant increases in mean hematocrit when compared with placebo. Meta-analysis revealed all formulations, including gel (3.0%, 95% CI 1.8-4.3), oral testosterone undecanoate (4.3%, 0.7-8.0), patch (1.4%, 0.2-2.6), intramuscular testosterone enanthate/cypionate (4.0%, 2.9-5.1), and intramuscular testosterone undecanoate (1.6%, 0.3-3.0) result in statistically significant increases in mean hematocrit when compared with placebo. When comparing all formulations against one another, intramuscular testosterone cypionate/enanthate were associated with a significantly higher increase in mean hematocrit compared to patch, but no differences in hematocrit between other formulations were detected.
CONCLUSIONS: All types of testosterone are associated with increased hematocrit; however, the clinical concern of this increase remains questionable, warranting future studies. This is the first network meta-analysis to quantify mean hematocrit change and compare formulations, given the absence of head-to-head trials.

BACKGROUND: Previous studies have suggested benefits of sodium glucose co-transporter 2 (SGLT2) inhibitors including improving glycemic control, lower body weight, uric acid-lowering effect and decreasing blood pressure. The aim of this study was to evaluate the effects of SGLT2 inhibitors on hematocrit (Hct) levels in patients with type 2 diabetes mellitus.
METHODS: Embase, CENTRAL, PubMed and other databases were searched from the establishment of the database through to July 2020. Randomized controlled trials (RCTs) involving patients with type 2 diabetes mellitus who were treated with SGLT2 inhibitors were analyzed using the random effects model. Stata 12.0 statistical software was used to estimate the weighted mean difference (WMD) and the 95% confidence intervals (CIs).
RESULTS: A total of 40 RCTs were included, comprising 21,050 patients. SGLT2 inhibitors resulted in a significant increase in Hct levels compared to patients treated with a placebo (WMD 2.67%, 95% CI, 2.53 to 2.82; P<0.001). Treatment with 2.5, 5, and 10 mg of dapagliflozin significantly increased Hct levels (WMD 1.96%, 2.27%, and 2.47%, respectively; P<0.001). Administration of 100 and 300 mg of canagliflozin also resulted in a significant increase in Hct (WMD 2.91% and 2.94%, respectively; P<0.001). Similarly, empagliflozin, at concentrations of 10 and 25 mg, caused a significant increase in Hct (WMD 3.39% and 3.44%, respectively; P<0.001). However, treatment with ipragliflozin (12.5 and 50 mg) and ertugliflozin (5 and 15 mg) only resulted in a slight increase in patient Hct levels (WMD 1.26% and 1.98%, respectively for ipragliflozin, P>0.05; WMD 2.24% and 2.64%, respectively for ertugliflozin; P>0.05).
CONCLUSIONS: SGLT2 inhibitors, as a class of drugs, increased Hct levels in patients with type 2 diabetes, and this increase was slightly more pronounced at higher doses compared to lower doses.
BACKGROUND: The protocol of this study has been submitted to the PROSPERO platform (https://www.crd.york.ac.uk/PROSPERO/), and the registration number is CRD42020200699.