Fatigue and health-related quality of life in patients with immune thrombocytopenia: a longitudinal assessment in China.

BACKGROUND: There is lacking studies of longitudinally assessment of fatigue and health-related quality of life (HRQoL) among Chinese immune thrombocytopenia (ITP) adults. We aimed to evaluate changes in fatigue and HRQoL and identify the associated factors. METHODS: Patients' characteristics, Functional Assessment of Chronic Illness Therapy (FACIT-F) and the ITP-specific Patient Assessment Questionnaire (ITP-PAQ) scores at admission (T0), at discharge (T1), and three months after discharge (T2) were collected. Linear mixed effects models were used to examine changes over time. RESULTS: We included 175 patients. The mean score of FACIT-F at T0 was 37.2 and increased at T1 (39.0), while then decreased at T2 (34.7). Patients who were single, retired, had persistent ITP, splenomegaly had more severe fatigue, whereas those who had not received any prior treatment and had a bleeding score of 0 at admission had milder fatigue. The mean score of ITP-PAQ was 57.7 at T0, then gradually increased to 60.3 at T1 and 62.8 at T2. Patients with persistent ITP and those who have never received treatment for ITP have better HRQoL. CONCLUSION: ITP adults' fatigue and HRQoL were impaired. Patients' fatigue improved at discharge but worsened at three months after discharge, while HRQoL gradually improved over time.

Cost-Effectiveness of a Quality Improvement Initiative for the Clinical Management of Children with Newly Diagnosed Immune Thrombocytopenia.

OBJECTIVE: To assess the cost-effectiveness of an evidence-informed institutional protocol for physicians that encouraged management of children with newly diagnosed immune thrombocytopenia (ITP) with observation over active therapy, where appropriate. STUDY DESIGN: We conducted a probabilistic cost-effectiveness analysis from an institutional perspective using a decision tree with a 1 year time horizon. Patient-level data were retrospectively ascertained for children diagnosed in pre-protocol (2007-2009) and post-protocol (2013-2018) time periods. ITP resolution was defined as achieving a sustained platelet count of >100 × 103/µL at 9-12 months after diagnosis. Outpatient care and inpatient costs were obtained from the institution and provincial sources. Intervention costs accounted for quality improvement initiative preparation and staff physician training. Incremental costs, incremental effects, and CIs were calculated from 10 000 model iterations. RESULTS: Forty-eight patients were followed for 1 year in the pre-protocol period and 84 in the post-protocol period. After protocol implementation, an average cost savings per child managed of $2055 (95% CI: $656, $3890) Canadian Dollars was observed, as was a higher proportion of resolved ITP cases. The implementation strategy remained less costly and more effective in 99.7% of model iterations. CONCLUSIONS: Implementation of an evidence-informed institutional protocol to guide physicians toward increased uptake of observation over active therapy when managing children with newly diagnosed ITP resulted in significant cost savings on a per case basis, even after accounting for training-related costs. Though the long-term cost implications regarding the sustainability of the intervention are not yet known, it is anticipated that continued institutional savings could occur.

Anti-PF4 testing for vaccine-induced immune thrombocytopenia and thrombosis and heparin induced thrombocytopenia: Results from a UK National External Quality Assessment Scheme exercise April 2021.

BACKGROUND: Vaccine-induced immune thrombocytopenia and thrombosis (VITT) following the administration of the AstraZeneca (AZ) ChAdOx1 nCOV-19 vaccine has recently been reported. The associated clinical and laboratory features have included thrombosis at unusual sites, thrombocytopenia, and raised D-dimers with positivity for IgG anti-platelet factor 4 (PF4) antibodies. OBJECTIVES: A UK National External Quality Control Assessment Scheme external quality control exercise was carried out by distributing liquid and lyophilized samples from a subject with VITT, a pool of samples from subjects with classical heparin-induced thrombocytopenia (HIT), and a non-VITT/non-HIT case to 85 centers performing HIT testing. METHODS: Participating centers employed their locally validated testing methods for HIT assays. RESULTS: The lyophilized and liquid samples were found to be commutable for the ELISA assays used in the detection of anti-PF4 antibodies. The Aeskulisa, Stago, Hyphen, and LIFECODES anti-PF4 ELISA assays successfully detected the VITT antibody, whereas the Acustar HIT, Werfen LIA, and the Stago STIC assays did not. CONCLUSION: It is important that clinical and laboratory teams are aware of the limitations of some anti-PF4 assays when using them to aid diagnosis of VITT syndrome.

Diagnostic characteristics of immature platelet fraction for the assessment of immune thrombocytopenia.

The diagnosis of immune thrombocytopenia (ITP) remains an exclusion, as a specific biomarker is missing. We aimed to investigate the diagnostic characteristics, establish a cut-off point for reticulated platelets, and compare it with the clinical exclusion diagnosis used in the assessment of ITP. Forty-one patients with ITP and 187 healthy individuals were enrolled in Santa Maria, Brazil. Sysmex XE-5000 was used to measure IPF. We obtained an IPF cut-off point of 6.3% with a sensitivity of 92.7% (95% CI: 80.1-98.5) and a specificity of 92.5% (95% CI: 87.8-95.8). The area under the curve was 0.97. The kappa coefficient was 0.85 (95% CI: 0.75-0.95), which shows high agreement between methods. The positive (PPV) and negative predictive values (NPV) were 81.25% and 96.42%, respectively. From the cut-off point, kappa index, PPV, and NPV obtained, it is possible to conclude that IPF can be an efficient laboratory marker for diagnosing ITP.

Incidence and prevalence of immune thrombocytopenia under the copayment waiver policy for pediatric patients in Korea: Data from the National Health Claims Database.

The purpose of this study was to investigate the epidemiology of immune thrombocytopenia (ITP) under the copayment waiver policy for pediatric patients in Korea. The data were collected from the National Health Insurance Claims Database of Korea. ITP was identified based on the diagnostic code D69.38 from the Korean Standard Classification of Diseases. Patients between one and 18 years old, who had at least one health insurance claim for ITP as a final diagnosis, from 1 January 2016, to 31 December 2017, were analyzed. Prevalent cases were defined as patients who used, at least one time, any medical services coded as D69.38. Incident cases were defined as patients who did not use D69.38 coded medical services during the prior year and were newly registered in 2017. The prevalence and incidence of ITP were 24.53 and 13.39 per 100,000 persons. The peak rates were observed in 1-year-old patients. The gender-specific prevalence of ITP was significantly higher in one-year-old males than females. According to the change-point analysis, we found that the prevalence and incidence diminished rapidly at the ages of four and three, respectively. This Korean population-based epidemiological study of ITP provided meaningful insights into the current epidemiology of ITP and demonstrated the implications of interpreting epidemiologic studies to reflect age categorizing and health care system characteristics.

The incidence and clinical burden of immune thrombocytopenia in pediatric patients in the United States.

Immune thrombocytopenia (ITP) is the most common bleeding disorder diagnosed in children. Characterized by low platelet counts, it leads to reduced clotting abilities and an increased tendency to bleed. The disorder in children is often self-limiting. However, approximately 25% of children develop persistent or chronic ITP, and bleeding associated with thrombocytopenia can be life-threatening. The current incidence of ITP in the US and the characterization of the illness among children being managed in routine clinical practice are sparsely reported. This retrospective cohort study leveraged a large US-based commercial claims database to estimate the current incidence of pediatric ITP, the uptake of ITP treatments, and the occurrence of clinical outcomes of interest. Overall, the incidence of ITP in patients <18 years was 8.8 (95% confidence interval; 8.5-9.1) per 100,000 person-years from 2011 to 2016. Within two years of ITP onset, >31% of patients received IVIg and/or oral corticosteroids. Other ITP therapies were less common. During this same time period, 50% had at least one bleeding event (ecchymosis, epistaxis, gastrointestinal hemorrhage, etc.), 24% were hospitalized for a bleeding event, and 62% had at least one ITP-related hospitalization. The majority of patients experiencing these events did so within the first month following ITP onset. Our findings confirm the rarity of ITP and relatively low likelihood of chronic disease in young patients, but reveal that for a significant proportion of patients in the newly diagnosed phase, clinical consequences can be serious. Further study of improved treatment methods throughout the disease course is warranted.

Assessment of Self-Administration of Romiplostim in Patients with Immune Thrombocytopenic Purpura after Receipt of Home Administration Training Materials: a Cross-Sectional Study.

INTRODUCTION: Romiplostim is a subcutaneously administered thrombopoietin-receptor agonist approved in the European Union for self-administration (or administration by a caregiver) in selected adult patients with chronic primary immune thrombocytopenia refractory to other treatments. To mitigate the risk of medication errors due to self-administration, the manufacturer has implemented additional risk minimisation measures (RMM) in the form of a Home Administration Training (HAT) pack to support the training of both healthcare professionals (HCPs) (guide and checklist for patient selection and training) and patients (a preparation mat, quick guide booklet, step-by-step guide, self-administration diary and DVD/video). OBJECTIVE: The primary objective was to estimate the proportion of patients/caregivers who administered romiplostim correctly after HAT pack training. METHODS: A multicentre observational study was conducted to evaluate the effectiveness of the HAT pack by recording data on a standardised collection form during direct observation of patients/caregivers in the act of administering romiplostim at the first standard-of-care visit 4 weeks after training with the HAT pack. RESULTS: Among the 40 patients/caregivers enrolled across 12 study centres in eight European countries, 35 [87.5%; 95% confidence interval (CI) 73.9-94.5] administered romiplostim correctly, and five (12.5%; 95% CI 5.5-26.1) did not. CONCLUSION: The correct administration of romiplostim by most patients/caregivers supports the effectiveness of the HAT pack as an additional risk minimisation tool in the population and setting of this study.

Cost per response analysis of strategies for chronic immune thrombocytopenia.

OBJECTIVES: This analysis estimated the cost per response and the incremental cost per additional responder of romplostim, eltrombopag, and the "watch-and-rescue" (monitoring until rescue therapies are required) strategy in adults with chronic immune thrombocytopenia (ITP). STUDY DESIGN: The decision tree is designed to estimate the total cost per response for romiplostim, eltrombopag, and watch and rescue over a 24-week time horizon; cost-effectiveness was evaluated in terms of incremental cost per additional responder. METHODS: Model inputs including response rates, bleeding-related episode (BRE) rates, and costs were estimated from registrational trial data, an independent Bayesian indirect comparison, database analyses, and peer-reviewed publications. Costs were applied to the proportions of patients with treatment response and nonresponse (based on platelet count). The total cost per response and the incremental cost per additional responder for each treatment were calculated. Sensitivity analyses and alternative analyses were performed. RESULTS: With higher total costs and greater treatment efficacy, romiplostim and eltrombopag had a lower 24-week cost per response and a lower average number of BREs than watch and rescue. Eltrombopag was weakly dominated by romiplostim. The incremental cost-effectiveness ratio of romiplostim versus watch and rescue was $46,000 per additional responder. The model results are most sensitive to response rates of romiplostim and watch and rescue and the BRE rate for splenectomized nonresponders. Alternative analyses results were similar to the base case. CONCLUSIONS: In adults with chronic ITP, romiplostim represents an efficient way to achieve response, with lower costs per response than eltrombopag; both romiplostim and eltrombopag had lower costs per response than watch and rescue.

Performance characteristics of an automated latex immunoturbidimetric assay [HemosIL® HIT-Ab(PF4-H)] for the diagnosis of immune heparin-induced thrombocytopenia.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a prothrombotic drug reaction caused by platelet-activating anti-PF4/heparin antibodies. Given time-sensitive treatment considerations, a rapid and accurate laboratory test for HIT antibodies is needed. AIMS: To determine operating characteristics for the HemosIL® HIT-Ab(PF4/H), a rapid, on-demand, fully-automated, latex immunoturbidimetric assay (LIA), for diagnosis of HIT. METHODS: We evaluated LIA sensitivity, specificity, negative (NPV) and positive predictive value (PPV), negative (LR-) and positive likelihood ratio (LR+), using citrated-plasma from 429 patients (prospective cohort study of 4Ts scoring; HIT, n=31), and from consecutive HIT patients (n=125), using reference standard serotonin-release assay (SRA). Comparators included two PF4-dependent enzyme-immunoassays (EIAs). We used stratum-specific likelihood ratios (SSLRs) to determine how differing magnitudes of LIA-positivity influenced post-test probability of HIT. RESULTS: LIA operating characteristics were: sensitivity=97.4% (152/156); specificity=94.0% (374/398); PPV=55.6% (30/54); and NPV=99.7% (374/375). At manufacturers' cutoffs, LIA specificity and PPV were superior to the EIAs. Although a negative LIA pointed strongly against HIT (LR-, 0.034), the post-test probability was ~2% with high 4Ts score. The LIA's LR+ was high (16.0), with SSLRs rising substantially with greater LIA-positivity: 5.7 (1.0-4.9U/mL), 31 (5.0-15.9U/mL), and 128 (≥16U/mL). A LIA-positive result (at 1.0 cutoff) indicated at least 24% HIT probability (low 4Ts score), rising to 90% with high 4Ts score. CONCLUSIONS: Although approximately 1 in 40 SRA-positive patients tested LIA-negative, the LIA's high NPV and PPV indicate that this rapid assay is useful for the diagnostic evaluation of HIT, including in low pre-test situations.

Length of stay, hospitalization cost, and in-hospital mortality in US adult inpatients with immune thrombocytopenic purpura, 2006-2012.

PURPOSE: In this study, we examined the length of stay, hospitalization cost, and risk of in-hospital mortality among US adult inpatients with immune thrombocytopenic purpura (ITP). METHODS: We analyzed nationally representative data obtained from Nationwide/National Inpatient Sample database of discharges from 2006 to 2012. RESULTS: In the US, there were an estimated 296,870 (95% confidence interval [CI]: 284,831-308,909) patient discharges recorded for ITP from 2006 to 2012, during which ITP-related hospitalizations had increased steadily by nearly 30%. The average length of stay for an ITP-related hospitalization was found to be 6.02 days (95% CI: 5.93-6.10), which is 28% higher than that of the overall US discharge population (4.70 days, 95% CI: 4.66-4.74). The average cost of ITP-related hospitalizations was found to be US$16,594 (95% CI: US$16,257-US$16,931), which is 48% higher than that of the overall US discharge population (US$11,200; 95% CI: US$11,033-US$11,368). Gender- and age-adjusted mortality risk in inpatients with ITP was 22% (95% CI: 19%-24%) higher than that of the overall US discharge population. Across diagnosis related groups, length of stay for ITP-related hospitalizations was longest for septicemia (7.97 days, 95% CI: 7.55-8.39) and splenectomy (7.40 days, 95% CI: 6.94-7.86). Splenectomy (US$25,262; 95% CI: US$24,044-US$26,481) and septicemia (US$18,430; 95% CI: US$17,353-US$19,507) were associated with the highest cost of hospitalization. The prevalence of mortality in ITP-related hospitalizations was highest for septicemia (11.11%, 95% CI: 9.60%-12.63%) and intracranial hemorrhage (9.71%, 95% CI: 7.65%-11.77%). CONCLUSION: Inpatients with ITP had longer hospital stay, bore higher costs, and faced greater risk of mortality than the overall US discharge population.

Increasing observation rates in low-risk pediatric immune thrombocytopenia using a standardized clinical assessment and management plan (SCAMP® ).

An observational approach is recommended in newly diagnosed children with immune thrombocytopenia (ITP) at low risk of bleeding; however, there is no standard definition of risk. A standardized clinical assessment and management plan (SCAMP® ), a modifiable practice guideline, was implemented and revised (SCAMP-1 and SCAMP-2) and applied to 71 newly diagnosed patients with ITP. The Buchanan and Adix bleeding score guided treatment and was modified by stratifying by low- and high-risk grade 3 bleeding in SCAMP-2. Observation rates increased from 40% to 74% from SCAMP-1 to SCAMP-2 (P < 0.05) with no bleeding complications. We propose a modified bleeding score that increased observation rates in low-risk patients with ITP.

Hospitalizations in pediatric patients with immune thrombocytopenia in the United States.

To examine utilization and outcomes in pediatric immune thrombocytopenia (ITP) hospitalizations, we used ICD-9 code 287.31 to identify hospitalizations in patients with ITP in the 2009 HCUP KID, an all-payer sample of pediatric hospitalizations from US community hospitals. Diagnosis and procedure codes were used to estimate rates of ITP-related procedures, comorbidity prevalence, costs, length of stay (LOS), and mortality. In 2009, there were an estimated 4499 hospitalizations in children aged 6 months-17 years with ITP; 43% in children aged 1-5 years; and 47% with emergency department encounters. The mean hospitalization cost was $5398, mean LOS 2.0 days, with 0.3% mortality (n = 13). With any bleeding (15.2%, including gastrointestinal 2.0%, hematuria 1.3%, intracranial hemorrhage [ICH] 0.6%), mean hospitalization cost was $7215, LOS 2.5 days, with 1.5% mortality. For ICH (0.6%, n = 27), mean cost was $40 209, LOS 8.5 days, with 21% mortality. With infections (14%, including upper respiratory 5.2%, viral 4.9%, bacterial 1.9%), the mean cost was $6928, LOS 2.9 days, with 0.9% mortality. Septic shock was reported in 0.3% of discharges. Utilization included immunoglobulin administration (37%) and splenectomies (2.3%). Factors associated with higher costs included age >6 years, ICH, hematuria, transfusion, splenectomy, and bone marrow diagnostics (p < 0.05). In conclusion, of the 4499 hospitalizations with ITP, mortality rates of 1.5%, 21%, and 0.9% were seen with any bleeding, ICH, and infection, respectively. Higher costs were associated with clinically significant bleeding and procedures. Future analyses may reveal effects of the implementation of more recent ITP guidelines and use of additional treatments.

Conflicts of interest and clinical recommendations: comparison of two concurrent clinical practice guidelines for primary immune thrombocytopenia developed by different methods.

The growing influence of practice guidelines has increased concern for potential sources of bias. Two recent guidelines for primary immune thrombocytopenia (ITP) provided a unique opportunity for a systematic comparison of different methods of practice guideline development. One guideline (International Consensus Report [ICR]) was supported by pharmaceutical companies that produce products for ITP. The ICR panel members were selected for expertise in ITP; 16 (73%) reported associations with pharmaceutical companies. The other guideline was sponsored by the American Society of Hematology (ASH); panel members were selected for lack of conflicts and for expertise in guideline development as well as for ITP. Discrepancies were conspicuous when the guidelines addressed treatment. In contrast to the ASH guideline, the ICR gave stronger recommendations for agents manufactured by companies from which the ICR or its panel members received support. These data provide direct evidence that differences in financial support and methods of evidence evaluation can influence recommendations.

Patterns of inpatient care for newly diagnosed immune thrombocytopenia in US children's hospitals.

OBJECTIVE: Although recent evidence-based guidelines for the management of immune thrombocytopenia (ITP) recommend a conservative, observation-based approach for the majority of patients with newly diagnosed pediatric ITP, current practice patterns are unknown. This study used the Pediatric Health Information System database to examine patterns of inpatient care in newly diagnosed ITP in freestanding US children's hospitals and to examine geographic differences in care. METHODS: Data were extracted from Pediatric Health Information System for all newly diagnosed ITP admissions aged 1 to 18 years discharged between January 2008 and December 2010. Clinical data obtained included age, gender, length of stay, diagnoses, medications, and discharge status. RESULTS: We identified 2314 unique patients meeting the study diagnosis of newly diagnosed ITP. Noncutaneous bleeding occurred in 12% of patients (intracranial hemorrhage 0.6%), with epistaxis the most commonly reported symptom. Ninety percent of hospitalized patients received ITP-directed therapy, with intravenous immunoglobulin G the most commonly used therapy (78% of patients). We identified significant variation by geographic region in treatment strategies, length of stay, hospital charges, and likelihood of readmission. CONCLUSIONS: A substantial number of children with newly diagnosed ITP continue to be hospitalized and receive intravenous medications, although the majority of these patients do not have clinical bleeding events during the admission. By using these results as a backdrop, future studies will be able to identify if the number of ITP admissions, costs of care, and geographic variability in care decrease with the dissemination and implementation of recently published guidelines.

Standardization of bleeding assessment in immune thrombocytopenia: report from the International Working Group.

In a previous publication on new terminology, definitions, and outcome criteria for immune thrombocytopenia (ITP), the International Working Group (IWG) on ITP acknowledged that response to treatment should consist of clinically meaningful end points such as bleeding manifestations and that platelet count may not be the ideal parameter for capturing the benefits of therapy. The IWG now proposes a consensus-based ITP-specific bleeding assessment tool (ITP-BAT) with definitions and terminology consistent with those adopted for other bleeding disorders. Bleeding manifestations were grouped into three major domains: skin (S), visible mucosae (M), and organs (O), with gradation of severity (SMOG). Each bleeding manifestation is assessed at the time of examination. Severity is graded from 0 to 3 or 4, with grade 5 for any fatal bleeding. Bleeding reported by the patient without medical documentation is graded 1. Within each domain, the same grade is assigned to bleeding manifestations of similar clinical impact. The "worst bleeding manifestation since the last visit" (observation period) is graded (a suitable database collection form is provided), and the highest grade within each domain is recorded. The SMOG system provides a consistent description of the bleeding phenotype in ITP, and the IWG unanimously supports its adoption and validation in future clinical studies.

[Assessment of an immature platelet fraction (IFP%) in the diagnosis of thrombocytopenia]. / Valeur du pourcentage de plaquettes réticulées dans le diagnostic étiologique d'une thrombopénie.

Reticulated platelets are young platelets containing mRNA. They reflect the rate of thrombopoesis. The aim of this study was to evaluate the reliability of the percentage of reticulated platelets (IPF%) as a diagnostic test for thrombocytopenia pathogenesis. IPF% was measured using XE 2100 Sysmex. An IPF% reference range in 52 healthy individuals was established as 1-4.5% with a median 2.2%. In all the 13 patients with idiopathic thrombocytopenic purpura IPF% was increased (median 11.8, range 5.3-54.3%). Only 7 out of 18 patients with disseminated intravascular coagulation had high IPF% (median 5.4%, range 2.9-14.1%). Surprisingly, IPF% was increased in 17 out of 22 patients with acute leukaemia (median 9.7%, range 0.9-41.9%). In CIVD, IPF% values correlated with the severity of the illness. Increased values in acute leukaemia could not be explained by non specific staining but by delayed maturation of reticulated platelets. A high IPF% does not substantiate hyperdestructive thrombocytopenia but a diagnosis of idiopathic thrombocytopenic purpura should be questioned if IPF% is not raised.

Validation of claims-based diagnostic codes for idiopathic thrombotic thrombocytopenic purpura in a commercially-insured population.

It was the purpose of the present study to validate administrative claims codes for idiopathic thrombotic thrombocytopenic purpura (TTP) in a commercially-insured US population. Patients with at least one medical claim with ICD-9 code 446.6X between 1/1/2001 and 5/31/2008 were identified in the HealthCore Integrated Research Database (HIRD). A chart abstraction form was developed to enable case determination for patients identified by the claims code. Two clinical experts, not involved in the design of the study, reviewed the abstracted medical record data and determined whether definite evidence supporting the diagnosis of TTP was present. The positive predictive value (PPV) of the claims coding algorithm for cases assessed by both reviewers was computed. The claims algorithm was further refined and the PPV of the refined algorithm was computed. One hundred eighty-nine abstracted charts were reviewed by two clinical experts; 86 were assessed to have definite evidence supporting the diagnosis of TTP (PPV 45.5% [86/189; 95% confidence interval (CI), 38.3-52.9%]). Refinement of the claims algorithm first included the use of plasma exchange treatment, resulting in 103 potential cases, of which 67 were assessed to have definite evidence supporting the diagnosis of TTP (PPV 65.0%; 95% CI, 55.0-74.2%). Further refinement of the claims algorithm ruled out alternative diagnoses that may mimic TTP; 34 were assessed to have definite evidence supporting the diagnosis of TTP (PPV 72.3% [34/47; 95% CI, 57.4-84.4%]).Our findings demonstrate the difficulty of confirming the diagnosis of rare disorders that lack definite diagnostic criteria, and indicate that more complex claims coding algorithms are necessary for identifying these disorders.

Cost and mortality associated with hospitalizations in patients with immune thrombocytopenic purpura.

Immune thrombocytopenic purpura (ITP) is associated with low platelet counts and, consequently, a high risk of adverse events leading to hospitalization. However, there are few data on the clinical and economic burden of hospitalizations for ITP. The Nationwide Inpatient Sample (NIS) database of discharges, a stratified 20% sample of all United States (US) community hospitals across all payers, was used to evaluate discharges in ITP patients. We developed nationally representative numbers of discharges in ITP patients from 2003 to 2006 based on diagnosis codes. Using appropriate weights for each NIS discharge, we created national estimates of average cost, length of stay, and in-hospital mortality for specific groups of ITP-related hospitalizations. Approximately 129,000 discharges occurred between 2003 and 2006 in ITP patients. The average cost associated with all discharges in 2008 dollars was 16,476, with a 6.4-day length of stay and in-hospital mortality of 3.8%. In contrast, the average cost of all hospitalizations in the US population during the same period was 10,039, the average length of stay was 4.8 days, and in-hospital mortality was 2.5%. Mortality risk was higher for ITP patients than for the standard US population adjusted for age and gender, with a relative mortality ratio of 1.5 (95% CI: 1.4-1.6). On the basis of a nationally representative sample of US discharge records from 2003 to 2006, hospitalization with ITP represents an economically and clinically important event. ITP was associated with higher costs, longer stays, and more in-hospital deaths on average than all other hospitalized patients combined.