Childhood autoimmune hemolytic anemia: A scoping review.

BACKGROUND AND OBJECTIVE: Autoimmune hemolytic anemia (AIHA) is a rare but important cause of morbidity in pediatric hematology patients. Given its rarity, there is little high-quality evidence on which to base the investigation and management of pediatric AIHA. This scoping review aims to summarize the current evidence and highlight key gaps to inform future studies. METHODS: This review searched MEDLINE and the Cochrane CENTRAL Trials Register from 2000 to November 03, 2023. Experimental and observational studies reporting AIHA diagnostic criteria, laboratory workup, or treatment/management in populations with at least 20% of patients ≤18 years were included. RESULTS: Forty-three studies were included, with no randomized controlled trials identified. AIHA diagnostic criteria, diagnostic tests, and treatments were highly variable. First-line treatment approaches include corticosteroids, intravenous immunoglobulin, or both. Approaches to AIHA resistance to first-line therapy were widely variable between studies, but most commonly included rituximab and/or cyclosporine. CONCLUSIONS: We identify a heterogenous group of observational studies into this complex, immune-mediated disorder. Standardized definitions and classifications are needed to guide collaborative efforts needed to study this rare disease. The work done by the CEREVANCE group provides an important paradigm for future studies.

Quality of Life in Transfusion-Dependent Thalassemia Patients in Greece Before and During the COVID-19 Pandemic.

OBJECTIVES: The peak of the COVID-19 pandemic was a challenging situation for transfusion-dependent thalassemia (TDT) patients. The objectives of this study were to measure the quality of life (QoL) in TDT patients during the COVID-19 lockdown restriction measures, compare the results with the pre-COVID-19 era, and evaluate the influence of sociodemographic and clinical factors on QoL. METHODS: This was a cross-sectional study of 110 consecutively selected adult TDT patients, during the stringent lockdown restriction measures implemented in Greece. All participants completed a combination of 2 QoL questionnaires, the generic Short-Form Health Survey 36 version 2 and the disease-specific Transfusion-Quality of life (TranQol). We used the "1/2 SD method," a distribution-based approach to calculate minimal clinically important differences and clinically compare the QoL scores between the pre-COVID-19 and post-COVID-19 era. A backward stepwise linear regression was selected to explore the influence of potential predictors on TranQol scores. RESULTS: The Short-Form Health Survey 36 version 2 and TranQol scores remained low but not clinically different compared with the pre-COVID-19 era. Older, married, and higher educated TDT patients exhibited significantly lower TranQol summary scores. The patients who reported a negative effect of the COVID-19 pandemic had significantly lower TranQol scores in summary and all subdomains except for school and career. CONCLUSIONS: During the COVID-19 pandemic, the overall QoL of TDT patients was clinically similar to the status of the pre-COVID-19 era. Nevertheless, most of the significant QoL subdomains were negatively affected, and distinct groups of TDT patients were more vulnerable.

Shared decision-making related to treatment of haemophilia: A scoping review of influential factors and available support tools.

INTRODUCTION: Treatment selection in haemophilia is increasingly challenging given evolving therapeutic options and the need for individualization. Shared decision-making (SDM) approaches have recently gained interest, though a synthesis of available studies is lacking. AIM: A scoping review was conducted to summarize literature reporting on factors impacting treatment SDM in haemophilia and tools or models available to support such decisions. METHODS: PubMed, Embase, the Cochrane Library, Web of Science and grey literature were searched for studies published through August 2023. Original studies reporting on facilitators and barriers to haemophilia SDM and SDM tools were included and analyzed for themes, characteristics and gaps. RESULTS: A total of 625 records were identified and 14 unique studies were selected (factors influencing treatment SDM, n = 7; SDM tools, n = 7). The studies typically included input from persons with haemophilia, caregivers and healthcare practitioners (HCPs). Thematic organization of factors influencing SDM revealed three main categories: knowledge, patient characteristics and HCP-patient interactions. Availability of information was a commonly reported facilitator of SDM, while poor HCP-patient engagement was a commonly reported barrier. Tools varied in focus, with some facilitating general treatment SDM while others supported selection of certain therapy types. The studies underscored additional factors critical for SDM, such as alignment of HCP-patient perceptions, shared language and tailoring of tools to specific subpopulations. CONCLUSION: Few studies report on treatment SDM factors and tools in haemophilia; available tools vary considerably. It remains unclear whether published tools have been successfully implemented into clinical practice. Additional research is warranted.

A Cross-Sectional, Multicentric, Disease-Specific, Health-Related Quality of Life Study in Greek Transfusion Dependent Thalassemia Patients.

The assessment of health-related quality of life (HRQoL) in thalassemia offers a holistic approach to the disease and facilitates better communication between physicians and patients. This study aimed to evaluate the HRQoL of transfusion-dependent thalassemia (TDT) patients in Greece. This was a multicentric, cross-sectional study conducted in 2017 involving 283 adult TDT patients. All participants completed a set of two QoL questionnaires, the generic SF-36v2 and the disease-specific TranQol. Demographic and clinical characteristics were used to predefine patient subgroups. Significant factors identified in the univariate analysis were entered into a multivariate analysis to assess their effect on HRQoL. The SF-36 scores of TDT patients were consistently lower compared to the general population in Greece. The mean summary score of TranQol was relatively high (71 ± 14%), exceeding levels observed in national surveys in other countries. Employment emerged as the most significant independent factor associated with better HRQoL, whereas age had the most significant negative effect. This study represents the first comprehensive QoL assessment of a representative sample of the TDT population in Greece. The implementation of TranQol allowed for the quantification of HRQoL in Greece, establishing a baseline for future follow-up, and identifying more vulnerable patient subgroups.

Face validity of the Kids' ITP Tools (KIT) in the era of thrombopoietin receptor agonists.

The Kids' ITP Tools (KIT) is a questionnaire to assess quality of life of children with immune thrombocytopenia (ITP). The aim of this study was to update this previously validated tool to align with changes in clinical practice, specifically, treatment with thrombopoietin receptor agonists (TPO-RAs). Children aged 1-18 with ITP and/or their families were recruited to participate in interviews to review the KIT. Twenty-six interviews were conducted. Based on interview data from children and families, current guidelines, and expert opinion, five changes were made to the KIT in order to improve its face validity.

Quick, Effective Screening Tasks Identify Children With Medical Conditions or Disabilities Needing Physical Literacy Support.

PURPOSE: This study evaluated screening tasks able to identify children with medical conditions or disabilities who may benefit from physical literacy. METHOD: Children completed ≤20 screening tasks during their clinic visit and then the Canadian Assessment of Physical Literacy (2nd edition) at a separate visit. Total Canadian Assessment of Physical Literacy scores <30th percentile were categorized as potentially needing physical literacy support. Receiver operator characteristic curves identified assessment cut points with 80% sensitivity and 40% specificity relative to total physical literacy scores. RESULTS: 223 children (97 girls; 10.1 [2.6] y) participated. Physical activity adequacy, predilection, and physical competence achieved ≥80% sensitivity and ≥40% specificity in both data sets. Adequacy ≤ 6.5 had 86% to 100% sensitivity and 48% to 49% specificity. Daily screen time >4.9 hours combined with Adequacy ≤6.15 had 88% to 10% sensitivity and 53% to 56% specificity. CONCLUSIONS: Activity adequacy, alone or with screen time, most effectively identified children likely to benefit from physical literacy support. Adequacy and screen time questionnaires are suitable for clinical use. Similar results regardless of diagnosis suggest physical competence deficits are not primary determinants of active lifestyles. Research to enhance screening specificity is required.

Psychometric validation of the Pyruvate Kinase Deficiency Diary and Pyruvate Kinase Deficiency Impact Assessment in adults in the phase 3 ACTIVATE trial.

BACKGROUND: Pyruvate kinase (PK) deficiency is a rare hereditary disorder characterized by chronic hemolytic anemia and serious sequalae which negatively affect patient quality of life. This study aimed to psychometrically validate the first disease-specific patient-reported outcome (PRO) instruments: the 7-item PK Deficiency Diary (PKDD) and 12-item PK Deficiency Impact Assessment (PKDIA), designed to assess signs, symptoms, and impacts of PK deficiency in patients enrolled in the ACTIVATE global phase 3 study of mitapivat versus placebo (NCT03548220). METHODS: All validation analyses for the PKDD and PKDIA were performed on blinded data, with analyses on item integrity, scoring, reliability, and validity conducted on data from screening and baseline. Completion rates and baseline response distributions were characterized using descriptive statistics. Item response modelling was used to inform a weighted scoring system. Reliability was assessed by internal consistency and test-retest reliability; and validity by convergent and known-groups analyses. RESULTS: Of the 80 adults enrolled, baseline data were available for 77 (96.3%) and 78 (97.5%) patients for the PKDD and PKDIA, respectively. Item responses skewed right, indicating that mean values exceeded median values, especially for items utilizing a 0-10 numeric scale, which were subsequently recoded to a 0-4 scale; 4 items were removed from the PKDIA due to redundancy or low relevance to the trial population. Both the PKDD and PKDIA demonstrated high internal consistency (McDonald's coefficient ω = 0.86 and 0.90, respectively), test-retest reliability (intra-class coefficients of 0.94 and 0.87, respectively), and convergent validity with other PROs (linear correlation coefficients [|r|] between 0.30-0.73 and 0.50-0.82, respectively). CONCLUSIONS: The findings provide evidence of validity and reliability for the PKDD and PKDIA, the first disease-specific PRO measures for PK deficiency, and can therefore increase understanding of, and more accurately capture, the wider impact of PK deficiency on health-related quality of life. Trial registration ClinicalTrials.gov, NCT03548220. Registered June 07, 2018; https://www. CLINICALTRIALS: gov/ct2/show/NCT03548220 .

Pyruvate kinase (PK) deficiency is a rare genetic blood disorder with a wide range of signs and symptoms that may have a negative impact on patients' quality of life. Patient-reported outcome (PRO) instruments are tools that assess how a disease affects a patient from the patient's perspective. These instruments must go through a validation process to make sure they truly capture the patient's experience with their condition or its treatment. This study aimed to validate two new PRO instruments in adult patients enrolled in the ACTIVATE clinical trial (NCT03548220), where patients with PK deficiency received the drug mitapivat or a placebo. These two new PRO instruments are the first to be developed specifically for PK deficiency: the PK Deficiency Diary (PKDD), a daily diary that asks 7 questions to measure the core signs and symptoms of PK deficiency, and the PK Deficiency Impact Assessment (PKDIA), a weekly questionnaire with 12 questions to assess the impact of PK deficiency on a patient's life. The results of this study showed that the PKDD and PKDIA properly and reliably measured the signs, symptoms, and impacts of PK deficiency that they aimed to capture. These findings indicate that the PKDD and PKDIA are the first validated PROs specifically for PK deficiency and can help improve the understanding of the impact of PK deficiency on patients' quality of life.

Integration of Patient-reported Outcome Measures in Pediatric Hematology: A Qualitative Methods Study.

Patient-reported outcome measures (PROMs) are self-reported questionnaires that allow patients and families to evaluate health-related experiences without influence or oversight from health care professionals. This study aimed to rate the relevance of existing PROMs for pediatric hematology patients, as identified by a recent systematic review, as well as to evaluate the receptivity of electronic PROM integration into clinical practice. Focus groups and interviews were conducted with children (10) and parents (19) impacted by nonmalignant hematological disorders, as well as with health care professionals (6). We observed strong support for the TranQol in thalassemia (100% for both parents [P] and children [C]); the Canadian Haemophilia Outcomes-Kids' Life Assessment Tool (CHO-KLAT) (100% P, 75% C) and Haemophilia Quality of Life questionnaire (Haemo-QoL) (100% P and C) in hemophilia; the Pediatric Quality of Life Inventory (PedsQL) Sickle Cell Module (75% P, 100% C); and the Kids ITP Tool in immune thrombocytopenia (100% P, 66.7% C). Generic tools such as the PedsQL Generic were met with mixed support. Electronic PROM integration received universal support. We obtained strong support for the integration of a web-based platform into clinical practice and a preference for disease-specific PROMs over generic PROMs. Future projects may explore the development of a child-friendly Canadian web-based platform to standardize quality-of-life evaluation within the clinical encounter.

Pediatric refractory immune thrombocytopenia: A systematic review.

Pediatric immune thrombocytopenia (ITP) is an acquired disorder associated with autoimmune destruction and impairment of platelet production in children. Some children exhibit poor or transient response to ITP-directed treatments and are referred to as having refractory ITP (rITP). There is currently no consensus on the definition of rITP, nor evidence-based treatment guidelines for patients with rITP. After a survey of pediatric ITP experts demonstrated lack of consensus on pediatric rITP, we pursued a systematic review to examine the reported clinical phenotypes and treatment outcomes in pediatric rITP. The search identified 253 relevant manuscripts; following review, 11 studies proposed a definition for pediatric rITP with no consensus amongst them. Most definitions included suboptimal response to medical management, while some outlined specific platelet thresholds to define this suboptimal response. Common attributes identified in this study should be used to propose a comprehensive definition, which will facilitate outcome comparisons of future rITP studies.

Evaluating the impact of thrombopoietin receptor agonist medications on patient outcomes and quality of life in paediatric immune thrombocytopenia through semi-structured interviews.

Over the last decade, treatment of immune thrombocytopenia (ITP) in children has advanced to include thrombopoietin receptor agonist (TPO-RA) medications. Concurrently, there has been an increased emphasis on patient-reported outcomes-especially quality of life-to guide treatment. Assessing the impact of TPO-RAs on quality of life in paediatric ITP is therefore a priority. In this single-centre integrative mixed-methods study, a cohort of children with ITP prescribed a TPO-RA was identified. These children and/or their caregivers were invited to participate in semi-structured interviews focussed on quality-of-life measures. Independently, a retrospective chart review collected ITP-related data (platelet count, bleeding events) and TPO-RA data (dosing, side effects). Among the 23 eligible patients, 20 were represented in interviews. On chart review, 11/20 patients responded to TPO-RA by meeting platelet count criteria of ≥50 × 109 /L for six or more weeks in the absence of rescue therapy. In interviews with these children and/or their parents, 19/20 expressed the TPO-RA had 'worked', with 11/20 reporting benefit to mood and 11/20 reporting increased participation in activities/sports. Concerns were raised in interviews about TPO-RA medication cost (17/20), medication administration (10/20) and potential side effects (10/20). In conclusion, this study suggests that TPO-RA use in children with ITP improves quality of life.

Patient-Reported Outcomes Measurement in Radiation Oncology: Interpretation of Individual Scores and Change over Time in Clinical Practice.

Tools for measuring patients' perceived health and quality of life, such as patient-reported outcome measures (PROMs), inform clinical decisions for patients requiring radiation therapy. However, there may be inconsistencies in how patients interpret and respond to PROMs due to cultural, environmental, personal, or experiential factors. Differential item functioning (DIF) and response shift (RS) refer to differences in the meaning of PROMs between patients or over time (respectively). DIF and RS can threaten the accurate interpretation and use of PROMs, potentially resulting in erroneous conclusions about effectiveness, and flawed individual-level clinical decision-making. Given the empirical evidence of DIF and RS, we aim to review clinical implications and solutions for addressing DIF and RS by providing vignettes from collaborative examinations with workshop participants, as well as the literature. By making these methodological concepts accessible and relevant, for practice, clinicians may feel more confident to ask clarifying questions of patients when PROM scores and the contextual patient information do not align. PROM scores need to be interpreted via dialogue with the patient to avoid misinterpretation due to DIF and RS, which could diminish patient-clinician communication and impede shared decision-making. This work is part of an interdisciplinary knowledge translation initiative focused on the interpretation of PROM scores by clinically-oriented audiences.

Health-related quality of life and fatigue in children and adults with pyruvate kinase deficiency.

Pyruvate kinase deficiency (PKD) is the most common cause of congenital nonspherocytic hemolytic anemia. Although recognition of the disease spectrum has recently expanded, data describing its impact on health-related quality of life (HRQoL) are limited. In this prospective international cohort of 254 patients (131 adults and 123 children) with PKD, we used validated measures to assess the impact of disease on HRQoL (EuroQol 5-Dimension Questionnaire, Pediatric Quality of Life Inventory Generic Core Scale version 4.0, and Functional Assessment of Cancer Therapy-Anemia) and fatigue (Patient Reported Outcomes Measurement Information System Fatigue and Pediatric Functional Assessment of Chronic Illness Therapy-Fatigue). Significant variability in HRQoL and fatigue was reported for adults and children, although individual scores were stable over a 2-year interval. Although adults who were regularly transfused reported worse HRQoL and fatigue compared with those who were not (EuroQol-visual analog scale, 58 vs 80; P = .01), this difference was not seen in children. Regularly transfused adults reported lower physical, emotional, and functional well-being and more anemia symptoms. HRQoL and fatigue significantly differed in children by genotype, with the worst scores in those with 2 severe PKLR mutations; this difference was not seen in adults. However, iron chelation was associated with significantly worse HRQoL scores in children and adults. Pulmonary hypertension was also associated with significantly worse HRQoL. Additionally, 59% of adults and 35% of children reported that their jaundice upset them, identifying this as an important symptom for consideration. Although current treatments for PKD are limited to supportive care, new therapies are in clinical trials. Understanding the impact of PKD on HRQoL is important to assess the utility of these treatments. This trial was registered at www.clinicaltrials.gov as #NCT02053480.

Poor outcome after hematopoietic stem cell transplantation of patients with unclassified inherited bone marrow failure syndromes.

Classification of inherited bone marrow failure syndromes (IBMFSs) according to clinical and genetic diagnoses enables proper adjustment of treatment. Unfortunately, 30% of patients enrolled in the Canadian Inherited Marrow Failure Registry (CIMFR) with features suggesting hereditability could not be classified with a specific syndromic diagnosis. We analyzed the outcome of hematopoietic stem cell transplantation (HSCT) in unclassified IBMFSs (uIBMFSs) and the factors associated with outcome. Twenty-two patients with uIBMFSs and 70 patients with classified IBMFSs underwent HSCT. Five-year overall survival of uIBMFS patients after HSCT was inferior to that of patients with classified IBMFSs (56% vs 76.5%). The outcome of patients with uIBMFS who received cord blood was significantly lower than that of patients who received other stem cell sources (14.8% vs 90.9%). Engraftment failure was higher among patients with uIBMFS who received cord blood than those who received bone marrow. None of the following factors were significantly associated with poor survival: transfusion load, transplant indication, the intensity of conditioning regimen, human leukocyte antigen-identical sibling/alternative donor. We suggest that identifying the genetic diagnosis is essential to modulate the transplant procedure including conditioning agents and stem cell sources for better outcome and the standard cord blood transplantation (CBT) should be avoided in uIBMFS.

The impact of extended half-life factor concentrates on patient reported health outcome measures in persons with hemophilia A and hemophilia B.

BACKGROUND: Recombinant factors VIII and IX Fc (rFVIIIFc/rFIXFc) were the only available extended half-life (EHL) products in Canada during 2016 to 2018. OBJECTIVES: To evaluate if patient-reported outcome measures (PROMs) improved in Canadian persons with hemophilia who switched from standard half-life (SHL) to EHL products (rFVIIIFc/rFIXFc). PATIENTS/METHODS: This prospective cohort study enrolled persons with moderate or severe hemophilia aged ≥6 years who switched to rFVIIIFc/rFIXFc (2016-2018) and those who remained on SHL. Health-related quality of life (HRQoL) was assessed using the Haemophilia-specific Quality of Life (Haem-A-QoL) and 36-item Short-Form Survey (SF-36) at baseline, 3-months, 12 months, and 24 months. Other PROMs included the Work Productivity and Impairment Questionnaire, chronic pain scale, partner/parent ratings of mood, International Physical Activity Questionnaire, and Treatment Satisfaction Questionnaire for Medication. We identified meaningful changes using minimally important difference for SF-36 and responder definition for Haem-A-QoL. RESULTS: We enrolled 25 switchers (16 rFVIIIFc, 9 rFIXFc) and 33 nonswitchers. Those switched to rFVIIIFc/rFIXFc had improved overall HRQoL, and improved subscale physical activity, mental health, and social functioning at 3 months. The rFIXFc switchers had improved chronic pain and ability to engage in normal activities while the rFVIIIFc switchers had improved treatment satisfaction. There was no change in work impairment after the switch. Observed improvement disappeared by 24 months in most domains. CONCLUSION: Switching from SHL to rFVIIIFc/rFIXFc resulted in short-term meaningful improvement in overall HRQoL and other PROMs in a small proportion. Longitudinal changes on PROMs are affected by ceiling effects and response shift, warranting further studies in instrument optimization in the era of EHL and nonfactor products.

Magnetic resonance imaging in boys with severe hemophilia A: Serial and end-of-study findings from the Canadian Hemophilia Primary Prophylaxis Study.

BACKGROUND: This study examined the structural outcomes for joints of boys with severe hemophilia A receiving frequency/dose-escalated primary prophylaxis using magnetic resonance imaging (MRI), and the importance of interval MRI changes. METHODS: Forty-six subjects (27 with interval studies) were evaluated by radiographs (X-rays) and mid- and end-of-study MRIs (using the International Prophylaxis Study Group scale), as part of the Canadian Hemophilia Prophylaxis Study. The primary outcome was the presence of MRI osteochondral findings. RESULTS: The median (range) time on study at the end-of-study MRI examination was 9.6 (4.8-16.0) years, during which 18 of 46 subjects (39%) had osteochondral changes in at least one joint. An interval change in MRI score of at least 1 point was observed in 44% of joints (43 ankles, 21 elbows, 4 knees); at least one joint showed this change in all 27 subjects. Self-reported interval hemarthrosis was associated with a higher likelihood of interval osteochondral change (odds ratio [OR], 1.49; 95% confidence interval [CI] = 1.08-2.06). Presence of synovial hypertrophy or hemosiderin on interval MRIs was associated with an OR of 4.71 (95% CI, 1.92-11.57) and 5.25 (95% CI, 2.05-13.40) of later osteochondral changes on MRI. DISCUSSION: MRI changes were seen in 39% of subjects. Interval index joint bleeding was associated with an increased risk of later MRI changes, and earlier soft-tissue changes were associated with subsequent osteochondral changes.

Phase 3 randomised trial of eltrombopag versus standard first-line pharmacological management for newly diagnosed immune thrombocytopaenia (ITP) in children: study protocol.

INTRODUCTION: Immune thrombocytopaenia (ITP) is an acquired disorder of low platelets and risk of bleeding. Although many children can be observed until spontaneous remission, others require treatment due to bleeding or impact on health-related quality of life. Standard first-line therapies for those who need intervention include corticosteroids, intravenous immunoglobulin and anti-D globulin, though response to these agents may be only transient. Eltrombopag is an oral thrombopoietin receptor agonist approved for children with chronic ITP who have had an insufficient response to corticosteroids, intravenous immunoglobulin or splenectomy. This protocol paper describes an ongoing open-label, randomised trial comparing eltrombopag to standard first-line management in children with newly diagnosed ITP. METHODS AND ANALYSIS: Randomised treatment assignment is 2:1 for eltrombopag versus standard first-line management and is stratified by age and by prior treatment. The primary endpoint of the study is platelet response, defined as ≥3 of 4 weeks with platelets >50×109/L during weeks 6-12 of therapy. Secondary outcomes include number of rescue therapies needed during the first 12 weeks, proportion of patients who do not need ongoing treatment at 12 weeks and 6 months, proportion of patients with a treatment response at 1 year, and number of second-line therapies used in weeks 13-52, as well as changes in regulatory T cells, iron studies, bleeding, health-related quality of life and fatigue. A planned sample size of up to 162 randomised paediatric patients will be enrolled over 2 years at 20 sites. ETHICS AND DISSEMINATION: The study has been approved by the centralised Baylor University Institutional Review Board. The results are expected to be published in 2023. TRIAL REGISTRATION NUMBER: NCT03939637.

Health services use by children identified as heterozygous hemoglobinopathy mutation carriers via newborn screening.

BACKGROUND: Newborn screening (NBS) for sickle cell disease incidentally identifies heterozygous carriers of hemoglobinopathy mutations. In Ontario, Canada, these carrier results are not routinely disclosed, presenting an opportunity to investigate the potential health implications of carrier status. We aimed to compare rates of health services use among children identified as carriers of hemoglobinopathy mutations and those who received negative NBS results. METHODS: Eligible children underwent NBS in Ontario from October 2006 to March 2010 and were identified as carriers or as screen-negative controls, matched to carriers 5:1 based on neighbourhood and timing of birth. We used health care administrative data to determine frequencies of inpatient hospitalizations, emergency department (ED) visits, and physician encounters through March 2012, using multivariable negative binomial regression to compare rates of service use in the two cohorts. We analyzed data from 4987 carriers and 24,935 controls. RESULTS: Adjusted incidence rate ratios (95% CI) for service use in carriers versus controls among children < 1 year of age were: 1.11 (1.06-1.17) for ED visits; 0.97 (0.89-1.06) for inpatient hospitalization; and 1.02 (1.00-1.04) for physician encounters. Among children ≥1 year of age, adjusted rate ratios were: 1.03 (0.98-1.07) for ED visits; 1.14 (1.03-1.25) for inpatient hospitalization and 0.92 (0.90-0.94) for physician encounters. CONCLUSIONS: While we identified statistically significant differences in health services use among carriers of hemoglobinopathy mutations relative to controls, effect sizes were small and directions of association inconsistent across age groups and health service types. Our findings are consistent with the assumption that carrier status is likely benign in early childhood.