Surveillance for Sickle Cell Disease - Sickle Cell Data Collection Program, Two States, 2004-2018.

PROBLEM/CONDITION: Sickle cell disease (SCD), an inherited blood disorder affecting an estimated 100,000 persons in the United States, is associated with multiple complications and reduced life expectancy. Complications of SCD can include anemia, debilitating acute and chronic pain, infection, acute chest syndrome, stroke, and progressive organ damage, including decreased cognitive function and renal failure. Early diagnosis, screenings and preventive interventions, and access to specialist health care can decrease illness and death. Population-based public health surveillance is critical to understanding the course and outcomes of SCD as well as the health care use, unmet health care needs, and gaps in essential services of the population affected by SCD. PERIOD COVERED: 2004-2018. DESCRIPTION OF THE PROGRAM: In 2015, CDC established the Sickle Cell Data Collection (SCDC) program to characterize the epidemiology of SCD in two states (California and Georgia). Previously, surveillance for SCD was conducted by two short-term projects: Registry and Surveillance System for Hemoglobinopathies (RuSH), which was conducted during 2010-2012 and included 2004-2008 data, and Public Health Research, Epidemiology, and Surveillance for Hemoglobinopathies (PHRESH), which was conducted during 2012-2014 and included 2004-2008 data. Both California and Georgia participated in RuSH and PHRESH, which guided the development of the SCDC methods and case definitions. SCDC is a population-based tracking system that uses comprehensive data linkages in state health systems. These linkages serve to synthesize and disseminate population-based, longitudinal data for persons identified with SCD from multiple sources using selected International Classification of Diseases, Ninth Revision, Clinical Modification, and Tenth Revision codes and laboratory results confirmed through state newborn screening (NBS) programs or clinic case reporting. Administrative and clinical data sources include state Medicaid and Children's Health Insurance Program databases, death certificates, NBS programs, hospital discharge and emergency department records, and clinical records or case reports. Data from multiple sources and years are linked and deduplicated so that states can analyze and report on SCD population prevalence, demographic characteristics, health care access and use, and health outcomes. The SCD case definition is based on an algorithm that classifies cases with laboratory confirmation as confirmed cases and those with a reported clinical diagnosis or three or more diagnostic codes over a 5-year period from an administrative data source as probable cases. In 2019, nine states (Alabama, California, Georgia, Indiana, Michigan, Minnesota, North Carolina, Tennessee, and Virginia) were funded as part of an SCDC capacity-building initiative. The newly funded states developed strategies for SCD case identification and data linkage similar to those used by California and Georgia. As of 2021, the SCDC program had expanded to 11 states with the addition of Colorado and Wisconsin. RESULTS: During 2004-2018, the cumulative prevalence of confirmed and probable SCD cases identified in California and Georgia was 9,875 and 14,777 cases, respectively. The 2018 annual prevalence count was 6,027 cases for California and 9,141 for Georgia. Examination of prevalence counts by contributing data source during 2014-2018 revealed that each data source captured 16%-71% of cases in California and 17%-87% in Georgia; therefore, no individual source is sufficient to estimate statewide population prevalence. The proportion of pediatric SCD patients (children aged 0-18 years) was 27% in California and 40% in Georgia. The percentage of females with SCD in California and Georgia was 58% and 57%, respectively. Of the cases with SCD genotyping data available (n = 5,856), 63% of patients had sickle cell anemia. SCDC data have been used to directly apprise health care providers and policymakers about health care needs and gaps for patients with SCD. For example, an SCDC Georgia assessment indicated that 10% of babies born during 2004-2016 with SCD lived more than a 1-hour drive from any SCD specialty care option, and another 14% lived within a 1-hour drive of a periodic SCD specialty clinic only. Likewise, an SCDC California assessment indicated that during 2016-2018, most patients with SCD in Los Angeles County lived approximately 15-60 miles from hematologists experienced in SCD care. A surveillance capacity and performance assessment of all 11 SCDC states during 2020-2021 indicated that states differed in the availability of data sources used for SCD surveillance and the time frames for accessing each state data source. Nonetheless, methods for standardizing reporting were developed across all participating states. INTERPRETATION: This report is the first comprehensive description of CDC's efforts in collaboration with participating states to establish, maintain, and expand SCD surveillance through the SCDC program to improve health outcomes for persons living with SCD. Findings from California and Georgia analyses highlighted a need for additional SCD specialty clinics. Despite different approaches, expansion of SCDC to multiple states was possible using standardized, rigorous methods developed across all participating states for reporting on disease prevalence, health care needs and use, and deaths. PUBLIC HEALTH ACTION: Findings from surveillance can be used to improve and monitor care and outcomes for persons with SCD. These and other SCDC analyses have had a role in opening new SCD clinics, educating health care providers, developing state health care policies, and guiding new research initiatives. Public health officials can use this report as a guiding framework to plan or implement surveillance programs for persons with SCD. Both data-related activities (data sources; patient identifiers; and obtaining, transferring, and linking data) and the administrative considerations (stakeholder engagement, costs and resources, and long-term sustainability) are crucial to the success of these programs.

Providers' Perspectives on Treating Patients With Thalassemia.

In recent years, California has experienced a steady rise in Asian immigration which has led to a corresponding increased prevalence of clinically significant thalassemia in this state. As part of the Public Health Research, Education and Surveillance for Hemoglobinopathies emoglobinopathies project, a survey was developed to collect information from California providers who care for thalassemia patients in an effort to better understand their practice patterns, barriers to providing care, and educational needs. When asked about educational needs, providers most frequently expressed a desire for care and management guidelines (65.3%), health educational materials for patients (47.2%), and information on complications and clinical outcomes (32.1%). Only one quarter of providers (24.0%) reported that all of their thalassemia patients have a coordinated care plan. The increase in California thalassemia cases highlights the importance of provider knowledge to effectively serve the patients in their communities. Provider education and dissemination of treatment standards can not only improve knowledge about the disease but also increase awareness about the importance of coordinating care among a multidisciplinary team of specialists. Improvement in these areas will help achieve the overarching goal of better outcomes and quality of life for patients with thalassemia.

Effectiveness of Clinical Decision Support Based Intervention in the Improvement of Care for Adult Sickle Cell Disease Patients in Primary Care.

INTRODUCTION: Although most patients with rare diseases like sickle cell disease (SCD) are treated in the primary care setting, primary care physicians may find it challenging to keep abreast of medication improvements and complications associated with treatment for rare and complex diseases. The purpose of this study was to evaluate the effectiveness of a clinical decision support (CDS) -based intervention system for transfusional iron overload in adults with SCD to improve management in primary care. METHODS: An electronic medical record based clinical decision support system for potential transfusional iron overload in SCD patients in primary care was evaluated. The intervention was implemented in 3 family medicine clinics with a control group of 3 general internal medicine clinics. Data were collected in the 6 months before the intervention and 6 months after the intervention. There were 47 patients in the family medicine group and 24 in the general internal medicine group. RESULTS: There was no management change in the control group while the intervention group improved primary care management from 0% to 44% (P < .001). CONCLUSION: A CDS tool can improve management of SCD patients in primary care.

The accuracy of hospital ICD-9-CM codes for determining Sickle Cell Disease genotype.

Sickle cell disease affects more than 100,000 individuals in the United States, among whom disease severity varies considerably. One factor that influences disease severity is the sickle cell disease genotype. For this reason, clinical prevention and treatment guidelines tend to differentiate between genotypes. However, previous research suggests caution when using a claimsbased determination of sickle cell disease genotype in healthcare quality studies. The objective of this study was to describe the extent of miscoding for the major sickle cell disease genotypes in hospital discharge data. Individuals with sickle cell disease were identified through newborn screening results or hemoglobinopathy specialty care centers, along with their sickle cell disease genotypes. These genotypes were compared to the diagnosis codes listed in hospital discharge data to assess the accuracy of the hospital codes in determining sickle cell disease genotype. Eighty-three percent (sickle cell anemia), 23% (Hemoglobin SC), and 31% (Hemoglobin Sß+ thalassemia) of hospitalizations contained a diagnosis code that correctly reflected the individual's true sickle cell disease genotype. The accuracy of the sickle cell disease genotype coding was indeterminate in 11% (sickle cell anemia), 12% (Hemoglobin SC), and 7% (Hemoglobin Sß+ thalassemia) and incorrect in 3% (sickle cell anemia), 61% (Hemoglobin SC), and 52% (Hemoglobin Sß+ thalassemia) of the hospitalizations. The use of ICD-9-CM codes from hospital discharge data for determining specific sickle cell disease genotypes is problematic. Research based solely on these or other types of administrative data could lead to incorrect understanding of the disease.

Emergency department utilization by Californians with sickle cell disease, 2005-2014.

BACKGROUND: Clinical care for children and adults living with sickle cell disease (SCD) is often provided in the emergency department (ED). Population-based surveillance data can be used to describe the ED utilization patterns of this patient population. PROCEDURE: A cohort of pediatric and adult California patients with SCD was identified from multiple data sources, and 10 years (2005-2014) of their treat-and-release ED utilization data were analyzed. RESULTS: Among a cohort of 4,636 patients with SCD, 4,100 (88%) had one or more treat-and-release ED visits. There were 2.1 mean annual visits per person for the cohort (median 0.7; range 0-185). In a single year (2005), 53% had 0 treat-and-release ED visits, 35% had 1-3 visits, 9% had 4-10 visits, and 3% had 11 or more visits; this highest utilization group accounted for 45% of all patients' ED visits. ED utilization in this cohort was highest among young adults and also higher among older adults than pediatric patients. CONCLUSION: The majority of identified patients in each of the 10 years did not go to the ED, but nearly all had one or more such visits over the full span of time. This study highlights the power and utility of a multisource longitudinal data collection effort for SCD. Further study of the segment of the population with highest ED utilization may highlight areas where changes in healthcare and health policy could improve and extend the lives of patients with SCD.

Defining Sickle Cell Disease Mortality Using a Population-Based Surveillance System, 2004 through 2008.

OBJECTIVE: Population-based surveillance data from California and Georgia for years 2004 through 2008 were linked to state death record files to determine the all-cause death rate among 12,143 patients identified with sickle cell disease (SCD). METHODS: All-cause death rates, by age, among these SCD patients were compared with all-cause death rates among both African Americans and the total population in the two states. All-cause death rates were also compared with death rates for SCD derived from publicly available death records: the compressed mortality files and multiple cause of death files. RESULTS: Of 12,143 patients identified with SCD, 615 patients died. The all-cause mortality rate for the SCD population was lower than the all-cause mortality rate among African Americans and similar to the total population all-cause mortality rates from birth through age 4 years, but the rate was higher among those with SCD than both the African American and total population rates from ages 5 through 74 years. The count of deceased patients identified by using population-based surveillance data (n=615) was more than twice as high as the count identified in compressed mortality files using SCD as the underlying cause of death alone (n=297). CONCLUSION: Accurate assessment of all-cause mortality and age at death requires long-term surveillance via population-based registries of patients with accurately diagnosed SCD.

Attitudes toward Management of Sickle Cell Disease and Its Complications: A National Survey of Academic Family Physicians.

Objective. Sickle cell disease (SCD) is a disease that requires a significant degree of medical intervention, and family physicians are one potential provider of care for patients who do not have access to specialists. The extent to which family physicians are comfortable with the treatment of and concerned about potential complications of SCD among their patients is unclear. Our purpose was to examine family physician's attitudes toward SCD management. Methods. Data was collected as part of the Council of Academic Family Medicine Educational Research Alliance (CERA) survey in the United States and Canada that targeted family physicians who were members of CERA-affiliated organizations. We examined attitudes regarding management of SCD. Results. Overall, 20.4% of respondents felt comfortable with treatment of SCD. There were significant differences in comfort level for treatment of SCD patients depending on whether or not physicians had patients who had SCD, as well as physicians who had more than 10% African American patients. Physicians also felt that clinical decision support (CDS) tools would be useful for treatment (69.4%) and avoiding complications (72.6%) in managing SCD patients. Conclusions. Family physicians are generally uncomfortable with managing SCD patients and recognize the utility of CDS tools in managing patients.

State-based surveillance for selected hemoglobinopathies.

PURPOSE: The lack of an ongoing surveillance system for hemoglobinopathies in the United States impedes the ability of public health organizations to identify individuals with these conditions, monitor their health-care utilization and clinical outcomes, and understand the effect these conditions have on the health-care system. This article describes the results of a pilot program that supported the development of the infrastructure and data collection methods for a state-based surveillance system for selected hemoglobinopathies. METHODS: The system was designed to identify and gather information on all people living with a hemoglobinopathy diagnosis (sickle cell diseases or thalassemias) in the participating states during 2004-2008. Novel, three-level case definitions were developed, and multiple data sets were used to collect information. RESULTS: In total, 31,144 individuals who had a hemoglobinopathy diagnosis during the study period were identified in California; 39,633 in Florida; 20,815 in Georgia; 12,680 in Michigan; 34,853 in New York, and 8,696 in North Carolina. CONCLUSION: This approach provides a possible model for the development of state-based hemoglobinopathy surveillance systems.

Incidence of sickle cell trait--United States, 2010.

Persons with sickle cell trait (SCT) are heterozygous carriers of an abnormal ß-globin gene that results in the production of an abnormal hemoglobin, Hb S, which can distort red blood cells (http://www.cdc.gov/ncbddd/sicklecell/facts.html). All state newborn screening (NBS) programs have provided universal sickle cell disease (SCD) screening for newborns since 2006. Screening for SCD detects both SCD and SCT. To obtain up-to-date measures of the occurrence of SCT among newborns by race/ethnicity and state of birth, data collected by state NBS programs in 2010 were examined. In 2010, the incidence of SCT in participating states was 15.5 per 1,000 newborns overall; 73.1 among black newborns and 6.9 among Hispanic newborns. Incidence by state ranged from 0.8 per 1,000 screened newborns in Montana to 34.1 per 1,000 in Mississippi. Although the occurrence of SCT varies greatly from state-to-state and among different races and ethnicities, every state and racial/ethnic population includes persons living with the condition. The period immediately following NBS is ideal for primary care providers and genetic counselors to begin educating the families of identified persons with SCT about potential health complications and reproductive considerations.

Public health surveillance of nonmalignant blood disorders.

Nonmalignant blood disorders currently affect millions of Americans, and their prevalence is expected to grow over the next several decades. This is owing to improvements in treatment leading to increased life expectancy of people with hereditary conditions, like sickle cell disease and hemophilia, but also the rising occurrence of risk factors for venous thromboembolism. The lack of adequate surveillance systems to monitor these conditions and their associated health indicators is a significant barrier to successfully assess, inform, and measure prevention efforts and progress toward national health goals. CDC is strengthening surveillance activities for blood disorders by improving and developing new methods that are tailored to best capture and monitor the epidemiologic characteristics unique to each disorder. These activities will provide a robust evidence base for public health action to improve the health of patients affected by or at risk for these disorders.

The use of US health insurance data for surveillance of rare disorders: hereditary hemorrhagic telangiectasia.

PURPOSE: To assess the utility of US health insurance data for surveillance of hereditary hemorrhagic telangiectasia, an autosomal-dominant blood vasculature disorder with an estimated prevalence of 1.5-2.0 per 10,000 persons worldwide. METHODS: We used 2005-2010 MarketScan Research Databases to identify individuals with employer-sponsored health insurance and International Classification of Disease, 9th Revision, Clinical Modification codes of 448.0 present in either one inpatient claim or two outpatient claims 30 days apart to define hereditary hemorrhagic telangiectasia. We examined frequencies of International Classification of Disease, 9th Revision, Clinical Modification codes for conditions that are complications of hereditary hemorrhagic telangiectasia among individuals with hereditary hemorrhagic telangiectasia and the general population to identify combinations of codes associated with hereditary hemorrhagic telangiectasia. RESULTS: Excluding observations from one state, the average prevalence of hereditary hemorrhagic telangiectasia was 0.3 per 10,000 persons. The reported prevalence rose with age from ~0.1 per 10,000 at ages <30 years to 1.0-1.1 per 10,000 at ages 70 years and above. The condition codes that were most specific to presumed hereditary hemorrhagic telangiectasia were lung arteriovenous malformations and upper gastrointestinal angiodysplasia. Combinations of those codes and codes for brain arteriovenous malformation and epistaxis were highly predictive of reporting of hereditary hemorrhagic telangiectasia, with 20-57% of enrollees with those codes also meeting the study definition for hereditary hemorrhagic telangiectasia. CONCLUSION: Hereditary hemorrhagic telangiectasia is underrecognized in US administrative data. Administrative health data can be used to identify individuals with combinations of signs that are suggestive of hereditary hemorrhagic telangiectasia. Studies are needed to test the hypothesis that referral for evaluation of individuals with administrative records suggestive of undiagnosed hereditary hemorrhagic telangiectasia could lead to diagnosis and access to life-saving treatments for both them and affected family members.

Elevated transferrin saturation, health-related quality of life and telomere length.

We sought to examine the relationship between elevated transferrin saturation (TS) and measures of health status (telomere length and patient-reported health-related quality of life) to assess whether elevated TS is associated with negative patient outcomes beyond increased risk for morbidity and mortality, using a cross-sectional analysis of the Hemochromatosis and Iron Overload Screening Study supplemented with assays for leukocyte telomere length in adults ≥25 years old (n = 669). Among individuals with elevated TS (≥45 % for women and ≥50 % for men), who also had a usual source of care, only 5.2 % reported ever being told by a doctor that they had an elevated iron condition. In a fully adjusted general linear regression model controlling for demographic characteristics as well as health conditions associated with iron overload, elevated TS versus non-elevated TS was associated with worse general health status (60.4 vs. 63.8, P < 0.05), mental health status (76.5 vs. 82.2, P < 0.0001) and shorter telomere length (241.4 vs. 261.3, P < 0.05). Increased surveillance of elevated TS may be in order as elevated TS is associated with decreased health status and very few patients with elevated TS are aware of their condition.

Telomere length and elevated iron: the influence of phenotype and HFE genotype.

Elevated body iron stores are associated with morbidity and mortality due to oxidative stress. Hereditary hemochromatosis, a common condition caused by HFE gene mutations, can lead to excess iron storage and disease but clinical penetrance of HFE gene mutations is low and many people with elevated iron stores lack HFE mutations. We analyzed data from the Hemochromatosis and Iron Overload Screening Study to assess the relationship among HFE genotype (individuals with either homozygous or compound heterozygous status for C282Y and/or H63D HFE mutations were defined as genotype positive, or G+), elevated iron phenotype (individuals exceeding gender-specific transferrin saturation and serum ferritin threshold levels were considered phenotype positive, or P+), and leukocyte telomere length, a marker of biological aging and cumulative oxidative stress. In unadjusted analyses in comparison to individuals who were G-P-, G+P- were not significantly different (OR 0.74; 95% CI 0.26-2.04), while the G+P+ (OR 2.03; 95% CI 1.15-3.56), and G-P+ (OR 2.24; 95% CI 1.5-3.29) had increased risk of short telomeres (<=25th percentile) rather than long telomeres (>=75th percentile). In analyses adjusting for age, gender, and race/ethnicity, the effect of individuals with elevated iron phenotypes having short telomeres persisted with G+P+ individuals (OR 1.94; 95% CI 1.02-3.72), and G-P+ individuals (OR 2.17; 95% CI 1.39-3.39) being significantly different from the G-P- group. In conclusion, elevated iron phenotype, but not HFE genotype, was associated with shortened telomeres. Further studies will be needed to determine whether telomere length provides a marker for morbidities specifically associated with iron overload.

Transferrin saturation and hospital length of stay and mortality in Medicare beneficiaries.

OBJECTIVES: To evaluate in a large, nationally representative cohort the association between high serum transferrin saturation (TS) and hospital length of stay and mortality in older adults. DESIGN: Prospective cohort. SETTING: Longitudinal analyses of the Third National Health and Nutrition Examination Survey linked to Medicare claims from 1991 through 2006. PARTICIPANTS: Medicare beneficiaries aged 65 and older at baseline. MEASUREMENTS: Transferrin saturation collected on each participant at baseline was characterized as <20.0%, 20.0% to 54.9%, and 55.0% and greater. Length of stay in the hospital and death in the hospital were primary outcomes. Analyses were adjusted for age, sex, race and ethnicity, education, and severity of illness. RESULTS: Individuals hospitalized during the study period (79.4%) with high (odds ratio (OR) = 2.54, 95% confidence interval (CI) = 1.05-6.12) or low (OR = 1.31, 95% CI = 1.07-1.62) TS had a significantly greater risk of death than those with moderate TS. Individuals with high TS had longer average length of stay per hospitalization (11.1 days, (standard error, SE 1.7 days), P = .01) than those with moderate TS (8.4 (0.3) days). Individuals with high TS also had more hospital days per year (8.6 (2.0) days, P = .04) than those with moderate TS (6.7 (0.5) days). CONCLUSION: High TS is associated with longer length of stay and death in the hospital (unweighted N = 3,847, weighted N = 28,395,464).

A national survey of hemochromatosis patients.

BACKGROUND: Hereditary hemochromatosis (HH) is a common genetic disease in the United States, but little is known about the diagnosis from the patient's perspective. The purpose of this study was to characterize the circumstances surrounding the diagnosis of HH and assess treatments and health information needs. METHODS: We surveyed US adults aged 18 years and older who were diagnosed with HH after 1996. Response rate was 46%, with a total sample size of 979. Respondents were asked about the use of genetic and clinical markers in their diagnosis, current treatments, and health information needs. RESULTS: Results were stratified by age, education, and income status. Total of 90.0% of women and 75.5% of men were genetically tested for HH (P < .01). Approximately half (52.5%) were diagnosed by a gastroenterologist, hematologist, or other specialty physician and half were diagnosed by a primary care provider. Most of the respondents thought their HH had improved with the initial treatment and most patients were still receiving treatment for HH. Patient interest in learning more about specific hemochromatosis topics was generally high. CONCLUSIONS: Since the introduction of genetic identification of HH, these tests have been used in the diagnosis of the majority of patients. Primary care physicians may need to be more aware HH and strategies for diagnosis.

Calcium channel blocker use and serum ferritin in adults with hypertension.

Iron overload cardiomyopathy is becoming more prevalent, and early recognition and intervention may alter outcomes. Calcium channels are key transporters of iron under iron-overloaded conditions, and potentially represent a new therapeutic target for iron overload. The purpose of this study was to examine the relationship between Calcium channel blocker (CCB) use and serum ferritin among adults with diagnosed hypertension. We analyzed the nationally representative NHANES (National Health and Nutrition Examination Survey) 1999-2002 for adults ≥40 years with diagnosed hypertension. The association between CCBs and serum ferritin was assessed using a t-test and adjusted multiple regressions.The study population included 2143 individuals (representing 37.4 million individuals, 42.0 % males). 12.6 % of the population reported taking CCBs in the last month. Individuals taking CCBs had lower mean serum ferritin (129.3 ng/mL versus 154.5 ng/mL, p = 0.02). After adjusting for age, sex, menopause and hysterectomy status for women, race/ethnicity, and C-reactive protein, mean serum ferritin for individuals taking CCBs was 26.3 ng/mL lower than for those not taking CCBs (p = 0.01). In an adjusted regression, individuals who took CCBs and had a daily vitamin C intake of ≥500 mg had a mean serum ferritin that was 60.1 ng/mL lower than people not taking CCBs and with daily vitamin C < 500 mg (p < 0.001). In conclusion, this study found an association between use of CCBs and lower serum ferritin levels in individuals with hypertension. Further studies are needed to assess the possible use of CCBs as non-traditional chelating agents for treatment of iron overload cardiomyopathy.

Iron overload: what is the role of public health?

Hereditary hemochromatosis type 1, also known as hereditary hemochromatosis classical (HHC), is an iron overload disorder associated, in most cases, with mutations of the hemochromatosis (HFE) gene. Although suggested algorithms for diagnosing iron overload are available, there are still questions about options for genetic and biochemical screening for hemochromatosis and duration of treatment. This article provides a summary of an expert workgroup meeting convened on September 24-25, 2009, entitled "Iron Overload: What is the Role of Public Health?" The purpose of the meeting was to enable subject matter experts to share their most recent clinical and scientific iron overload information and to facilitate the discussion of future endeavors, with special emphasis on the role of public health in this field. The two main topics were the research priorities of the field, including clinical, genetic, and public health issues, and the concerns about the validity of current screening recommendations for the condition.