Intravenous Immunoglobulin (IVIg) Utilization in Immune Thrombocytopenia (ITP): A Multi-Center, Retrospective Review

Immunoglobulin utilization in Canada: a comparative analysis of provincial guidelines and a scoping review of the literature

BACKGROUND

Canada has high immunoglobulin (IG) product utilization, raising concerns about appropriate utilization, cost and risk of shortages. Currently, there is no national set of standardized IG guidelines, and considerable variations exist among the existing provincial guidelines. The aims of this study were: (1) to compare the existing Canadian provincial guidelines on the use of IG products to identify their consistencies and differences and (2) to examine the existing research in Canada on IG supply and utilization following the establishment of IG guidelines to understand the scope of research and pinpoint the gaps.

METHODS

A comparative analysis accounted for the differences across provincial IG guidelines. We highlighted similarities and differences in recommendations for medical conditions. A scoping review of citations from MEDLINE, PubMed, Scopus and Embase databases was conducted for studies published from January 01, 2014, to April 12, 2023.

RESULTS

While provincial guidelines represented a considerable overlap in the medical conditions delineated and relatively uniform dose calculations, numerous differences were observed, including in recommendation categories, provision of pediatric dosing, and divergent recommendations for identical conditions based on patient demographics. The scoping review identified 29 studies that focused on the use of IG in Canada. The themes of the studies included: IVIG utilization and audits, the switch from IVIG to SCIG, patient satisfaction with IVIG and/or SCIG, the economic impact of self-administered SCIG versus clinically administered IVIG therapy, and the efficacy and cost-effectiveness of alternative medications to IG treatment.

CONCLUSION

The differences in guidelines across provinces and the factors influencing IVIG/SCIG use, patient satisfaction, and cost savings are highlighted. Future research may focus on clarifying costs and comparative effectiveness, exploring factors influencing guideline adherence, and evaluating the impact of updated guidelines on IG use and patient outcomes.

Geographic disparities in the care and outcomes in adult chronic immune thrombocytopenia

INTRODUCTION

Despite expert-based recommendations, real-world adherence to immune thrombocytopenia (ITP) guidelines is unclear. The impact of geographic and socioeconomic disparities on the quality of care and outcomes is unknown. We sought to determine the association between geographic remoteness and material deprivation on ITP care and outcomes.

METHODS

We conducted a multi-centre retrospective cohort study of adults with chronic ITP requiring a second-line therapy between 2012 and 2019 in the province of Alberta, Canada. Socioeconomic status was measured using the Pampalon material deprivation index quintiles. Geographic disparities were assessed by the driving distance to a major centre, with geographic remoteness defined as >200 km from major centre. We examined the impact of geographic and material deprivation on quality of care, resource utilization (hospitalizations, transfusions), and outcomes (major bleeding, all-cause mortality and ITP-related mortality). Cox proportional hazards models were used to examine the impact of geographic remoteness, rural residence and material deprivation on overall survival and ITP-related survival.

RESULTS

We included 326 ITP patients, median age of ITP diagnosis was 57 years, 182 (56 %) were female. Most patients (58 %) lived within 20 km of a major centre, whereas 49 (15 %) lived in a geographically remote area (>200 km). Geographic remoteness was significantly associated with material deprivation and lower likelihood of management by hematologists (84 % vs 99 %, P = 0.0001). It was also associated with lower rates of hepatitis C (71 % vs 89 %, P = 0.005) and hepatitis B testing (69 % vs 86 %, P = 0.03), and a non-significant trend towards lower rates of HIV testing (73 % vs 83 %, P = 0.051) compared with those <20 km from a major centre. Incomplete hyposplenic vaccinations among splenectomized patients (52 %), early splenectomy within 12 months of ITP diagnosis (35 %), inappropriate platelet transfusions (41 %), and inappropriate hospitalizations for asymptomatic thrombocytopenia (16 %) were common regardless of geographic distribution. There were 28 (9 %) ITP-related deaths (major bleeding or infections), most occurred within the first year of ITP diagnosis. Material deprivation, but not geographic remoteness, was an independent predictor of all-cause mortality (aHR 1.9, 95 % CI 1.1-3.3 in the most deprived quintile vs least deprived quintile). Rural residence trended towards increased hazard of ITP-related deaths (aHR 1.7, 95 % CI 0.9-3.2).

CONCLUSION

We demonstrated substantial deviations of ITP care from consensus guidelines, and geographic disparities in access to care and diagnostic workup. Future quality improvement initiatives are critical to improve the quality of care and reduce inequities.

Dentoalveolar Procedures in Immune Thrombocytopenia; Systematic Review and an Institutional Guideline

Background  Dentoalveolar procedures in immune thrombocytopenia (ITP) pose a risk of bleeding due to thrombocytopenia and infection due to immunosuppressive treatments. We aimed to systematically review the safety and management of dentoalveolar procedures in ITP patients to create practical recommendations.

Methods  PubMed, Embase, Cochrane, and Cinahl were searched for original studies on dentoalveolar procedures in primary ITP patients. We recorded bleeding- and infection-related outcomes and therapeutic strategies. Clinically relevant bleeding was defined as needing medical attention.

Results  Seventeen articles were included, of which 12 case reports/series. Overall, the quality of the available evidence was poor. Outcomes and administered therapies (including hemostatic therapies and prophylactic antibiotics) were not systematically reported. At least 73 dentoalveolar procedures in 49 ITP patients were described. The range of the preoperative platelet count was 2 to 412 × 10 ⁹ /L. Two clinically relevant bleedings (2%) were reported in the same patient of which one was life-threatening. Strategies used to minimize the risk of bleeding were heterogeneous and included therapies to increase platelet count, antifibrinolytics, local measures, and minimally invasive techniques. Reports on the occurrence of bleedings due to anesthetics or infection were lacking.

Conclusion  Based on alarmingly limited data, clinically relevant bleedings and infections after dentoalveolar procedures in ITP patients seem rare. Awaiting prospective and controlled studies to further evaluate these risks and the efficacy of therapeutic interventions, we provided our institutional guideline to guide the management of dentoalveolar procedures in ITP patients.

Successful Treatment of Idiopathic Thrombocytopenic Purpura After Liver Transplant: A Case Report

Idiopathic thrombocytopenic purpura, a common acquired bleeding disorder in pediatric patients, is an autoimmune disorder characterized by a low platelet count. Organ transplant can transfer such diseases, but the occurrence of idiopathic thrombocytopenic purpura after liver transplant is rare. Here, we report a 17-month-old girl who was diagnosed with idiopathic thrombocytopenic purpura and who had a history of liver transplant 11 months earlier. Treatment of cytomegalovirus and Epstein-Barr virus infection led to a successful outcome.

Occurrence of acute renal failure on the same day as immune globulin product administrations during 2008 to 2014

BACKGROUND

Acute renal failure (ARF) is a rare serious adverse event after immune globulin (IG) use. Our large claims-based study evaluated occurrence of same-day ARF after administration of different IGs and ascertained potential risk factors, during the 2008 to 2014 study period.

STUDY DESIGN AND METHODS

A retrospective cohort study was conducted using a large commercial administrative database. The cohort included individuals exposed to IG products as identified by procedure codes. ARF was ascertained using ICD-9-CM diagnoses. Unadjusted same-day ARF rates (per 1000 persons exposed) were estimated overall and by age, sex, and IG products. Regression analyses were conducted to control for confounding and assess potential risk factors.

RESULTS

Of 20,440 persons exposed, 163 (7.97 per 1000) had a recorded same-day ARF. The unadjusted nonzero same-day ARF rates (per 1000) ranged from 1.92 (95% confidence interval [CI], 0.05-10.69) for Hizentra to 16.97 (95% CI, 11.36-24.37) for Privigen and differed by sex. In multivariate analyses, compared to Gammagard Liquid, no significantly elevated ARF risks were identified with any IGs. A significantly lower odds ratio was identified with Gamunex, 0.53 (95% CI, 0.30-0.93). Age 45 and over, prior renal impairment, hypertension, and other factors were associated with increased risk of same-day ARF.

CONCLUSION

The study showed variation in the risk of IG-related ARF by age, sex, and IG products. The study results suggest the importance of recipient factors, such as older age and underlying health conditions. Variations in ARF occurrence may also be explained by product dosage, administration route and rate, and manufacturing processes, which warrant further evaluation.

Small molecule phagocytosis inhibitors for immune cytopenias

Immune cytopenias are conditions characterized by low blood cell counts, such as platelets in immune thrombocytopenia (ITP) and red blood cells in autoimmune hemolytic anemia (AIHA). Chronic ITP affects approximately 4 in 100,000 adults annually while AIHA is much less common. Extravascular phagocytosis and massive destruction of autoantibody-opsonized blood cells by macrophages in the spleen and liver are the hallmark of these conditions. Current treatment modalities for ITP and AIHA include the first-line use of corticosteroids; whereas, IVIg shows efficacy in ITP but not AIHA. One main mechanism of action by which IVIg treatment leads to the reduction in platelet destruction rates in ITP is thought to involve Fcγ receptor (FcγR) blockade, ultimately leading to the inhibition of extravascular platelet phagocytosis. IVIg, which is manufactured from the human plasma of thousands of donors, is a limited resource, and alternative treatments, particularly those based on bioavailable small molecules, are needed. In this review, we overview the pathophysiology of ITP, the role of Fcγ receptors, and the mechanisms of action of IVIg in treating ITP, and outline the efforts and progress towards developing novel, first-in-class inhibitors of phagocytosis as synthetic, small molecule substitutes for IVIg in ITP and other conditions where the pathobiology of the disease involves phagocytosis.

An evaluation of overall effectiveness and treatment satisfaction with intravenous immunoglobulin among patients with immune thrombocytopenia

BACKGROUND

A global assessment of patient satisfaction that considers therapeutic effect, toxicities, and convenience is needed to evaluate the acceptability of intravenous immunoglobulin (IVIG) as a treatment for patients with immune thrombocytopenia (ITP).

STUDY DESIGN AND METHODS

We performed a cross-sectional pilot study to assess the feasibility and usefulness of a treatment satisfaction questionnaire for adult patients with ITP receiving IVIG in an academic hematology clinic. Treatment satisfaction was evaluated by administration of a validated survey-based tool 7 days after IVIG administration. The tool assessed treatment satisfaction across four domains (effectiveness, toxicity, convenience, and global satisfaction); results were summarized with mean scores.

RESULTS

Twelve patients were enrolled (nine females; median age, 44 years; interquartile range, 35-69 years). Mean platelet increment after infusion was 54.2 × 10(9) /L (SD, 47.6 × 10(9) /L). Treatment satisfaction scores were highest in the side effect burden domain (88.2/100; SD, 19.3; higher scores indicate a lower burden of side effects). Six participants reported IVIG-associated toxicities; most were "slightly" or "not at all" dissatisfied by the impact of side effects. The domain with the lowest score was convenience (62.0/100; SD, 24.7).

CONCLUSION

The assessment of treatment satisfaction using a survey-based assessment tool was feasible for patients receiving IVIG and provided meaningful results that discriminated between domains. Patients found IVIG treatment to be inconvenient, but were satisfied with its tolerability as an ITP treatment. Larger studies are needed to determine the precise impact on each domain and the reproducibility of study results. Patient satisfaction scores can be used to compare different ITP treatments.

Incidence and natural history of intravenous immunoglobulin-induced aseptic meningitis: a retrospective review at a single tertiary care center

BACKGROUND

Aseptic meningitis is a rare but significant complication of intravenous immunoglobulin (IVIG) therapy. The majority of literature is limited to case reports, so the true incidence of this complication is uncertain.

STUDY DESIGN AND METHODS

A retrospective review of all cases of IVIG-associated adverse transfusion reactions was performed at London Health Sciences Centre (LHSC) from January 1, 2008, to December 31, 2013. All reported transfusion reactions were evaluated to identify cases of aseptic meningitis due to IVIG. All documented IVIG infusions and lumbar punctures performed during the study period were reviewed; patients with both interventions were identified and further chart review was performed to identify aseptic meningitis.

RESULTS

During our study period, 1324 unique patients received a total of 11,907 IVIG infusions (554,566 g) for various conditions. Eight cases of aseptic meningitis were identified, suggesting an overall incidence of 0.60% for all patients and 0.067% for all IVIG infusions. Patients presented with symptoms within 24 to 48 hours of the infusion and were treated with antibiotics initially. The reactions were self-limited, as symptoms self-resolved within 5 to 7 days. Treatment was supportive, with subsequent IVIG infusions likely requiring preinfusion medication or possibly a switch in product formulation.

CONCLUSION

This review of IVIG-induced aseptic meningitis over a 6-year period identifies a more robust estimate of incidence and risk of 0.60% and 0.067% for all patients and infusions, respectively. Given that this complication can mimic infectious meningitis and cause considerable morbidity, physicians need to be aware of this rare but important condition.