Clinical burden and healthcare resource utilization associated with managing transfusion-dependent ß-thalassemia in France.

OBJECTIVE: To describe the clinical burden and healthcare resource utilization associated with managing transfusion-dependent ß-thalassemia (TDT) in France. METHODS: We used the French National Health Data System (système national des données de santé) to identify eligible patients from January 1, 2012, to March 1, 2019. Inclusion criteria were a diagnosis of ß-thalassemia, ≥8 red blood cell (RBC) transfusion episodes per year in ≥2 consecutive years following the diagnosis, and ≥1 year of follow-up data. Patients were excluded if medical records showed evidence of sickle cell disease, α-thalassemia, hereditary persistence of fetal hemoglobin, or hematopoietic stem cell transplant. Clinical complications, mortality, treatment use, and healthcare resource utilization were evaluated. RESULTS: Overall, 331 eligible patients with TDT were identified. Mean age was 26.1 (standard deviation [SD]: 18.0) years, and 50.5% were male. Common clinical complications were endocrine (26.0%), hepatobiliary (22.7%), and cardiopulmonary (18.7%). Fifteen (4.5%) patients died during follow-up, with a mortality rate of 1.16 deaths per 100 person-years (mean age of death: 52.5 years [SD: 22]). Patients had a mean of 13.5 (SD: 5.2) RBC transfusion episodes and 11.2 (SD: 5.3) iron chelation therapy treatments per year. Healthcare resource utilization was substantial, with a mean of 14.8 inpatient hospitalizations (including 13.8 mean inpatient day cases) and 16.9 outpatient prescriptions per patient per year. CONCLUSIONS: Patients with TDT in France experience significant clinical complications, elevated mortality, and substantial healthcare resource utilization driven by frequent RBC transfusion episodes and inpatient hospitalizations. These results reinforce the need for disease-modifying therapies for this patient population.

Prevalence and cost of sickle cell disease in France: real-world analysis using data from the Echantillon Généraliste des Bénéficiaires.

Sickle cell disease (SCD) is a genetic disorder of the hemoglobin resulting in chronic anemia, hemolysis, and vaso-occlusions. Its treatment mostly relies on hydroxycarbamide, transfusions, and stem cell transplantation. This study aimed at describing the epidemiology and management of SCD in adolescent and adult patients in France. This was a retrospective study performed among SCD patients aged ≥12 years between 2016 and 2018 and controls. SCD patients were matched on a 1:3 ratio with a group of individuals with no diagnosis of SCD, referred as control group. The matching of SCD patients and controls was a direct matching based on age, sex, CMU-c status (which corresponds to free-of-charge complementary coverage for people with low resources) and geographical region of residence. SCD patients and their matched controls were followed-up for the same amount of time by adjusting controls' follow-up period to that of the associated patients. This study used claims data from the French representative 1/97th sample of health data system. The main outcomes were the patients' characteristics and treatments received, healthcare consumptions and related costs among SCD cases and controls. Between 2016 and 2018, 151 patients with ≥6 months of follow-up were identified out of the total population of 732,164 individuals. SCD prevalence extrapolated to the entire population [95% CI] was 19,502 [19,230, 19,778] in 2018. The median (Q1-Q3) age at inclusion date was 37.0 (25.0-48.0) years, with 69.5% of patients being female. The mean (SD) reimbursed cost over follow-up was €24,310 (89,167), mostly represented by hospitalization costs accounting for €21,156 (86,402). A switch in SCD management was observed with age, as younger patients presented more frequent hospitalizations and acute procedures, while older ones had more frequent medical visits and paramedical care. Mean (SD) annual costs were €25,680 (91,843) and vs. €3,227 (23,372) for patients and controls, respectively (p < 0.001), representing an extra cost of almost €150 million over the entire SCD population. This study highlighted the important costs related to SCD and the related medical need with treatment alternatives, which could be filled by the emergence of new therapies.

Comprehensive in silico and functional studies for classification of EPAS1/HIF2A genetic variants identified in patients with erythrocytosis.

Gain-of-function mutations in the EPAS1/HIF2A gene have been identified in patients with hereditary erythrocytosis that can be associated with the development of paraganglioma, pheochromocytoma and somatostatinoma. In the present study, we describe a unique European collection of 41 patients and 28 relatives diagnosed with an erythrocytosis associated with a germline genetic variant in EPAS1. In addition we identified two infants with severe erythrocytosis associated with a mosaic mutation present in less than 2% of the blood, one of whom later developed a paraganglioma. The aim of this study was to determine the causal role of these genetic variants, to establish pathogenicity, and to identify potential candidates eligible for the new hypoxia-inducible factor-2 α (HIF-2α) inhibitor treatment. Pathogenicity was predicted with in silico tools and the impact of 13 HIF-2b variants has been studied by using canonical and real-time reporter luciferase assays. These functional assays consisted of a novel edited vector containing an expanded region of the erythropoietin promoter combined with distal regulatory elements which substantially enhanced the HIF-2α-dependent induction. Altogether, our studies allowed the classification of 11 mutations as pathogenic in 17 patients and 23 relatives. We described four new mutations (D525G, L526F, G527K, A530S) close to the key proline P531, which broadens the spectrum of mutations involved in erythrocytosis. Notably, we identified patients with only erythrocytosis associated with germline mutations A530S and Y532C previously identified at somatic state in tumors, thereby raising the complexity of the genotype/phenotype correlations. Altogether, this study allows accurate clinical follow-up of patients and opens the possibility of benefiting from HIF-2α inhibitor treatment, so far the only targeted treatment in hypoxia-related erythrocytosis disease.

Case Report of Myelodysplastic Syndrome in a Sickle-Cell Disease Patient Treated with Hydroxyurea and Literature Review.

The safety profile of hydroxyurea (HU) in patients with sickle-cell disease (SCD) is relatively well known. However, despite the suspected association of HU with myeloid neoplasms in myeloproliferative neoplasms (MPN), and the publication of sporadic reports of myeloid malignancies in SCD patients treated with HU, the possible excess risk imparted by HU in this population having an increasing life expectancy has failed to be demonstrated. Herein, we report one case of myelodysplastic syndrome emanating from the results on safety and effectiveness of HU on the largest European cohort of 1903 HU-treated adults and children who were followed-up prospectively in an observational setting over 10 years, accounting for a total exposure of 7309.5 patient-years. A comparison of this single case with previously published similar cases did not allow us to draw any significant conclusions due to the paucity of these events.

Mitapivat in adult patients with pyruvate kinase deficiency receiving regular transfusions (ACTIVATE-T): a multicentre, open-label, single-arm, phase 3 trial.

BACKGROUND: Mitapivat, an oral activator of pyruvate kinase (PK) in red blood cells (RBCs), has shown significant improvements in haemoglobin and haemolysis among patients with pyruvate kinase deficiency who were not receiving regular transfusions. We aimed to evaluate the efficacy and safety of mitapivat in adults with pyruvate kinase deficiency receiving regular transfusions. METHODS: ACTIVATE-T was an open-label, single-arm, phase 3 trial conducted in 20 centres across Europe, North America, and Asia. Eligible participants were adults (aged ≥18 years) with a clinical laboratory confirmation of pyruvate kinase deficiency receiving regular transfusions (at least six episodes in the previous year). Participants received oral mitapivat during a 16-week dose-optimisation period (5 mg, 20 mg, 50 mg twice daily) and 24-week fixed-dose period. The primary endpoint was a reduction in transfusion burden (≥33% reduction in number of RBC units transfused during the fixed-dose period, compared with the participant's individual historical transfusion burden, standardised to 24 weeks). Efficacy and safety were assessed in all participants who received at least one dose of mitapivat. This trial is registered with ClinicalTrials.gov, NCT03559699, and is complete. FINDINGS: Between June 26, 2018, and Feb 4, 2020, 27 participants (20 [74%] female and seven [26%] male; 20 [74%] White, three [11%] Asian, and four [15%] not reported) were enrolled and received at least one dose of mitapivat. Median duration of exposure to mitapivat was 40·3 weeks (IQR 40·0-41·3). A reduction in transfusion burden by at least 33% was found in ten (37%) participants (95% CI 19-58; p=0·0002). The most common treatment-emergent adverse events were increase in alanine aminotransferase (ten [37%] participants), headache (ten [37%]), increase in aspartate aminotransferase (five [19%]), fatigue (five [19%]), and nausea (five [19%]). Two grade 3 treatment-emergent adverse events were related to study treatment: joint swelling (one participant [4%]) and an increase in aspartate aminotransferase (one participant [4%]). Three participants had serious treatment-emergent adverse events, none related to the study treatment: increased blood triglycerides, ovarian cyst, and renal colic (each in one participant [4%]). No treatment-related deaths were observed. INTERPRETATION: Mitapivat represents a novel therapy that can reduce transfusion burden in some adults with pyruvate kinase deficiency receiving regular transfusions, and is the first disease-modifying agent approved in this disease. FUNDING: Agios Pharmaceuticals.

Real-Life experience with hydroxyurea in patients with sickle cell disease: Results from the prospective ESCORT-HU cohort study.

Several controlled studies have evidenced good efficacy and short-term and mid-term safety profiles for hydroxyurea (HU), which has become the cornerstone for prevention of sickle-cell disease (SCD)-related vaso-occlusive crises. However, there are few large-scale reports on its long-term use and certain caregivers and patients have concerns about its safety. Following the licensing of HU in Europe for children and adults with severe forms of SCD, ESCORT-HU was designed as a Phase IV observational cohort study. It included 1906 participants, of whom 55% were adults. The most common hemoglobin (Hb) genotypes were HbSS (84.7%) and HbSß+ (7.0%). The median duration of follow-up was 45 months, for a total of 7309 patient-years of observation. The dose of HU after 1 year was 20.6 mg/kg/d for children and 16.3 mg/kg/d for adults. There was a statistically significant decrease in the number of vaso-occlusive episodes lasting >48 h, acute chest syndrome episodes, hospitalizations, and the percentage of patients requiring blood transfusions within the first 12 months relative to the year before enrolment. Neutropenia and thrombocytopenia were the most commonly reported adverse effects. No new HU toxicity was identified. Overall, 125 pregnancies were reported in 101 women and no malformations were observed in the neonates. There were 12 pregnancies for partners of male patients treated with HU. One case of fatal myelodysplastic syndrome was reported, for which a causal association with HU could not be excluded. This cohort study of patients with SCD highlights the positive benefit-to-risk ratio of HU in children and adults.

Impact of pre-eclampsia on renal outcome in sickle cell disease patients.

The long-term consequences of pre-eclampsia (PrE) for renal function have never been determined in patients with sickle cell disease (SCD). Between 2008 and 2015, we screened 306 pregnancies in women with SCD and identified 40 with PrE (13%). The control group consisted of 65 pregnant SCD patients without PrE. In multivariable analysis, PrE events were associated with an increase of 1 log of lactate dehydrogenase level (adjusted odds ratio, aOR = 3·83, P = 0·05), a decrease of 10 g/l of haemoglobin levels (aOR = 2·48, P = 0·006) and one or more vaso-occlusive crisis during pregnancy (aOR = 16·68, P = 0·002). Estimated glomerular filtration rate (eGFR) was similar in the two groups at steady state but was significantly lower in the PrE group after one year of follow-up and at last follow-up (130 vs 148 ml/min/1·73 m2 , P < 0·001 and 120 vs 130 ml/min/1·73 m2 , P < 0·001, respectively). In multivariable analysis, eGFR had returned to steady-state levels one year after pregnancy in patients without PrE but continued to decrease in patients with PrE (ß = -18·15 ml/min/1·73 m2 , P < 0·001). This decline was more marked at the end of follow-up (ß = -31·15 ml/min, P < 0·001). In conclusion, PrE episodes are associated with a significant risk of subsequent renal function decline in SCD patients.

Whole-blood phenotyping to assess alloimmunization status in transfused sickle cell disease patients.

It is essential to limit hemolytic transfusion reactions in polytransfused individuals, and the prevention of alloimmunization is a key solution. CD4+ T lymphocyte (TL) markers, particularly follicular T helper (Tfh) cells, may differentiate between responder and nonresponder alloimmunization statuses. We tested this hypothesis by studying the phenotype of CXCR5+PD1+ TLs in whole blood. Our results suggest that high levels of CXCR5+PD1+CD4+ TLs in whole blood may be a characteristic of nonalloimmunized patients. However, these cells did not display the phenotypic characteristics of active Tfh cells. Instead, a decrease in blood quiescent Tfh-cell levels was observed in nonalloimmunized polytransfused patients. High levels of CXCR5+PD1+CD4+ TLs may be associated with inhibitory signaling functions of T cells, as reflected by the low levels of PD1+ICOS+ cells in the nonalloimmunized polytransfused group. The description of these particular phenotypes, and their comparison among groups of patients, responders, and nonresponders, suggests that new immunological components should be considered when trying to understand posttransfusion alloimmunization.

Beneficial effects of endurance exercise training on skeletal muscle microvasculature in sickle cell disease patients.

Sickle cell disease (SCD) is a genetic hemoglobinopathy leading to 2 major clinical manifestations: severe chronic hemolytic anemia and iterative vaso-occlusive crises. SCD is also accompanied by profound muscle microvascular remodeling. The beneficial effects of endurance training on microvasculature are widely known. The aim of this study was to evaluate the effects of an endurance training program on microvasculature of skeletal muscle in SCD patients. A biopsy of the vastus lateralis muscle and submaximal incremental exercise was performed before and after the training period. Of the 40 randomized SCD patients, complete data sets from 32 patients were obtained. The training group (n = 15) followed a personalized moderate-intensity endurance training program, while the nontraining (n = 17) group maintained a normal lifestyle. Training consisted of three 40-minute cycle ergometer exercise sessions per week for 8 weeks. Histological analysis highlighted microvascular benefits in the training SCD patients compared with nontraining patients, including increases in capillary density (P = .003), number of capillaries around a fiber (P = .015), and functional exchange surface (P < .0001). Conversely, no significant between-group difference was found in the morphology of capillaries. Indexes of physical ability also improved in the training patients. The moderate-intensity endurance exercise training program improved the muscle capillary network and partly reversed the microvascular defects commonly observed in skeletal muscle of SCD patients. This trial was registered at www.clinicaltrials.gov as #NCT02571088.

Familial disclosure by genetic healthcare professionals: a useful but sparingly used legal provision in France.

Familial disclosure of genetic information is an important, long-standing ethical issue that still gives rise to much debate. In France, recent legislation has created an innovative and unprecedented procedure that allows healthcare professionals (HCPs), under certain conditions, to disclose relevant information to relatives of a person carrying a deleterious genetic mutation. This article will analyse how HCPs in two medical genetics clinics have reacted to these new legal provisions and show how their reticence to inform the patients' relatives on their behalf leads them to use this option sparingly.

Severe, non specific symptoms in non-typhoidal Salmonella infections in adult patients with sickle cell disease: a retrospective multicentre study.

BACKGROUND: Non-typhoidal salmonellosis (NTS) often occurs in children with sickle-cell disease (SCD) and remains a significant cause of mortality in developing countries. However, there is lack of reports on the clinical presentation, outcome and complications of NTS in adults with SCD. METHODS: We performed a chart review between 2006 and 2016 of adults SCD diagnosed with NTS in 3 referral centers monitoring approximately 3500 SCD adults. RESULTS: Twenty-three episodes of NTS were diagnosed among 22 SCD adults. Diagnosis was challenging: 65% (n = 15/23) of patients presented with vaso-occlusive crisis (VOC) and 30% had no fever. Isolated serotypes were: ser. Enteritidis (n = 8), ser. Typhimurium (n = 6), others (n = 3). We identified two patterns of infections: (1) bacteremic NTS (n = 15) with (n = 9) or without secondary foci of infections (n = 6); (2) non-bacteremic NTS with extra-intestinal foci of infection (n = 8), including primary bones/joints infections (n = 5). Half of patients with osteo-articular localization (n = 6/13) had a previous history of osteonecrosis (n = 2) or osteomyelitis (n = 4) at the same site. Morbidity was high, 6 patients (26%) were admitted to the intensive care unit, 14 patients (61%) required RBC transfusion for VOC. Half of the episodes (n = 12) required surgery (n = 10) or interventional radiology (n = 2) to control the infection. One patient presented a relapse of NTS bacteraemia one year after the first episode. CONCLUSIONS: Besides bloodstream infections, clinical presentation of NTS in adults with SCD is non-specific at admission. A triad including bacteraemia, secondary focis of infection and bone localizations was observed in 30% of cases.

Low-impact laparoscopic cholecystectomy is associated with decreased postoperative morbidity in patients with sickle cell disease.

BACKGROUND: Laparoscopic cholecystectomy (LC) is one of the most frequent surgeries performed in patients with sickle cell disease (SCD). LC in SCD patients is associated with a particularly high postoperative morbidity. The aim of the present study is to assess the safety and feasibility of cholecystectomy performed by mini-laparoscopy with low- and stable-pressure pneumoperitoneum (MLC + LSPP) and to compare the rate of postoperative SCD-related morbidity with standard LC. METHODS: Thirty-five consecutive SCD patients admitted between November 2015 and March 2017 for cholelithiasis requiring surgery were compared with an historical cohort of 126 SCD patients who underwent LC for the same indication. Operative variables, postoperative outcomes, patient and surgeon satisfaction, and costs were evaluated. RESULTS: MLC + LSPP exhibited a mean operative time comparable to LC (p = 0.169). Operative blood loss was significantly reduced in the MLC + LSPP group, and the suction device was rarely used (p = 0.036). SCD-related morbidity (including acute chest syndrome) was significantly higher in the LC group compared with the MLC + LSPP group (18.3 vs. 2.9%; p = 0.029). The mean times to resume ambulation (p = 0.018) and regular diet (p = 0.045) were significantly reduced in the MLC + LSPP group. The mean incision length (all trocars combined) was 28.22 mm for MLC + LSPP and 49.64 mm for LC patients (p < 0.0001). Multivariate regression analysis demonstrated that the only significant predictor of postoperative SCD-related morbidity was the surgical approach (odds ratio: 9.24). Patient and surgeon satisfaction were very high for MLC + LSPP. The mean total cost per patient (surgery and hospitalization) was not different between groups (p = 0.084). CONCLUSION: MLC + LSPP in SCD patients appears to be safe and feasible. Compared with LC, MLC + LSPP in SCD patients is associated with a significantly reduced incidence of postoperative SCD-related morbidity and more rapid ambulation and return to regular diet without increasing the total costs per patient.

Incidence and predictors of portal and splenic vein thrombosis after pure laparoscopic splenectomy.

BACKGROUND: Optimal modalities for diagnosis, treatment, and surveillance of portal or splenic vein thrombosis have not yet been defined. The present retrospective study aimed to investigate the role of computed tomography performed systematically before and after laparoscopic splenectomy to assess the incidence of portal or splenic vein thrombosis, predictors, and outcomes. METHODS: Computed tomography scans were obtained from 170 patients undergoing elective laparoscopic splenectomy between 2005 and 2015. Pre- and postoperative splenic vein diameter was measured at the splenoportal junction and at a distance of 2, 4, 6 cm from it. Univariate and multivariate analyses were used to identify portal or splenic vein thrombosis risk factors and predictors of treatment outcome. RESULTS: Overall, 68.2% of patients had benign hematologic diseases; 64.1% showed splenomegaly. Portal or splenic vein thrombosis occurred in 53.5% of patients (91/170), of whom 49.5% were asymptomatic. Preoperative splenic vein diameter measurements at 2, 4, and 6 cm from the splenoportal junction were significantly greater in portal or splenic vein thrombosis patients than in no-portal or splenic vein thrombosis patients. Patients with splenic vein diameter ≥8 mm at all measured sites had a greater risk of developing portal or splenic vein thrombosis (P = .009; odds ratio, 2.57; 95% confidence interval, 1.26-5.23). The majority of thromboses involved the distal splenic vein (45.1%, 41/91), and 41.7% of patients had thromboses located in multiple sites. Fully 71.4% showed complete resolution of portal or splenic vein thrombosis. Thrombus location at a single site predicted a favorable treatment outcome (P < .0001). CONCLUSION: Portal or splenic vein thrombosis is a frequent complication of splenectomy that occurs asymptomatically in half of cases. Computed tomography could have an important role in identifying patients at risk of developing portal or splenic vein thrombosis as well as in predicting portal or splenic vein thrombosis resolution.

Genome-wide association study of erythrocyte density in sickle cell disease patients.

Deoxy-hemoglobin S polymerization into rigid fibers is the direct cause of the clinical sequelae observed in sickle cell disease (SCD). The rate of polymerization of sickle hemoglobin is determined primarily by intracellular hemoglobin concentration, itself dependent on the amount of sickle hemoglobin and on red blood cell (RBC) volume. Dense, dehydrated RBC (DRBC) are observed in SCD patients, and their number correlates with hemolytic parameters and complications such as renal dysfunction, leg ulcers and priapism. To identify new genes involved in RBC hydration in SCD, we performed the first genome-wide association study for DRBC in 374 sickle cell anemia (HbSS) patients. We did not find genome-wide significant results, indicating that variants that modulate DRBC have modest-to-weak effects. A secondary analysis demonstrated a nominal association (P=0.003) between DRBC in SCD patients and a variant associated with mean corpuscular hemoglobin concentration (MCHC) in non-anemic individuals. This intronic variant controls the expression of ATP2B4, the main calcium pump in erythrocytes. Our study highlights ATP2B4 as a promising target for modulation of RBC hydration in SCD patients.

Arterio-venous fistula for automated red blood cells exchange in patients with sickle cell disease: Complications and outcomes.

Erythrocytapheresis (ER) can improve outcome in patients with sickle cell disease (SCD). A good vascular access is required but frequently it can be difficult to obtain for sickle cell patients. Arterio-venous fistulas (AVFs) have been suggested for ER in SCD supported by limited evidence. We report the largest cohort of ER performed with AVFs from three French SCD reference centers. Data of SCD patients undergoing ER with AVFs in the French SCD reference center were retrospectively collected. The inclusion criteria were: SS or Sß-Thalassemia and AVF surgery for ER. SCD-related complications, transfusion history, details about AVF surgical procedure, echocardiographic data before and after AVF, AVF-related surgical and hemodynamical complications were collected. Twenty-six patients (mean age 20.5 years, mean follow-up 68 months [11-279]) were included. Twenty-three patients (88.5%) required central vascular access before AVF. Fifteen AVFs (58%) were created on the forearm and 11 (42%) on the arm. Nineteen patients (73%) had stenotic, thrombotic or infectious AVF complications. A total of 0.36 stenosis per 1,000 AVF days, 0.37 thrombosis per 1,000 AVF days and 0.078 infections per 1.000 AVF days were observed. The mean AVF lifespan was 51 months [13-218]. One patient with severe pulmonary hypertension worsened after AVF creation and died. We report the first series of SCD patients with AVF for ER, demonstrating that AVFs could be considered as a potential vascular access for ER. Patients with increased risk for hemodynamic intolerance of AVFs must be carefully identified, so that alternative vascular accesses can be considered. Am. J. Hematol. 92:136-140, 2017. © 2016 Wiley Periodicals, Inc.

Talar Osteonecrosis Related to Adult Sickle Cell Disease: Natural Evolution from Early to Late Stages.

BACKGROUND: Little is known about the rate of, and factors affecting, progression of talar osteonecrosis related to sickle cell disease. Adult patients with sickle cell disease who presented with hip osteonecrosis were evaluated for talar osteonecrosis with radiographs and magnetic resonance imaging (MRI). Forty-five of them (75 tali) were diagnosed with talar osteonecrosis, and this group was evaluated for factors influencing the progression of the disease. METHODS: Forty-five patients with sickle cell disease and osteonecrosis of the talus were identified with radiographs and MRI between 1985 and 1995. Seven of these patients were homozygous for hemoglobin S (S/S genotype), 26 had hemoglobin S/hemoglobin C, and 12 had hemoglobin S/beta-thalassemia. The talar osteonecrosis was graded with radiographs and MRI. The patients were followed with clinical examination and radiographs every 6 months until talar collapse and every year after the collapse. RESULTS: The osteonecrosis was unilateral in 15 patients and bilateral in 30 at the time of the initial examination. Forty-five ankles were asymptomatic and 30 were symptomatic at the initial evaluation. MRI performed at the time of the most recent follow-up, and compared with MRI performed at diagnosis, did not show partial or total regression of the osteonecrosis in any of the patients, even those with asymptomatic stage-I osteonecrosis. At the time of the most recent follow-up (mean, 20 years; range, 15 to 25 years), pain and collapse had developed in all except 12 ankles. The stage of the osteonecrosis at the initial visit, pain, the genotype of the sickle cell disease, and the extent and location of the lesion in the talus were risk factors for progression of the disease. CONCLUSIONS: In the majority of the patients with sickle cell disease, osteonecrosis of the talus should be expected to show relevant clinical and radiographic evidence of progression over a long period. LEVEL OF EVIDENCE: Prospective Level II. See Instructions for Authors for a complete description of levels of evidence.