Growth and pulmonary outcomes during the first 2 y of life of breastfed and formula-fed infants diagnosed with cystic fibrosis through the Wisconsin Routine Newborn Screening Program

The association of human milk intake and outcomes in biliary atresia

OBJECTIVES

Human milk intake has many benefits which could influence outcomes in biliary atresia (BA). However, the role of human milk in BA has not been examined. We hypothesized that human milk intake would be associated with improved outcomes in BA.

METHODS

We assessed the impact of any human milk (AHM) as compared to formula only (FO) intake before Kasai portoenterostomy (KP) on outcomes in 447 infants with BA using the PROBE database (NCT00061828) post hoc. The primary outcome was clearance of jaundice (COJ = total bilirubin (TB) < 2 mg/dL by 3 months post-KP). Secondary outcomes included 2-year survival with native liver (SNL), bilirubin levels, cholangitis, ascites, and growth. We assessed the fecal microbiome (n = 8) comparing AHM versus FO.

RESULTS

At baseline, 211 infants received AHM and 215 received FO. 53.9% of AHM and 50.5% of FO achieved COJ (p = NS). SNL was insignificantly increased in AHM (odds ratio = 1.47, 95% confidence interval: 1.00-2.12, p = 0.053). TB decreased in AHM from 4 weeks to 3 months post-KP [4.8-4.0 mg/dL (p = 0.01)] unlike the FO group (4.9-4.9 mg/dL, p = 0.4). At 3 months post-KP, AHM infants had greater weight gain (1.88 ± 0.66 vs. 1.57 ± 0.73 kg, p < 0.001) and mid-upper arm circumference (12.9 ± 1.4 vs. 12.2 ± 1.7 cm, p < 0.001). Other secondary outcomes were not different. Microbiome differences were seen between AHM and FO.

CONCLUSIONS

Human milk intake in infants with BA did not significantly improve COJ or SNL. However, growth parameters were improved, and TB 3 months post-KP was decreased. Thus, human milk intake should not be discouraged. Prospective studies with detailed assessment of human milk intake are needed.

Breastfeeding, growth, and lung disease in the first 3 years of life in children with cystic fibrosis

BACKGROUND

The 2009 cystic fibrosis (CF) infant care guidelines recommend breastmilk as the initial feeding but do not address if/when it should be fortified or supplemented with formula to promote optimal growth and pulmonary health.

METHODS

We conducted a prospective multi-center cohort study in breastfed and formula-fed infants that included 172 infants with CF who were born during 2012-17, enrolled after newborn screening at age 1.9 ± 1.0 months, and evaluated growth and lung disease manifestations in the first 3 years of life.

RESULTS

Seventy-two percent of our study cohort was breastfed at birth, but 64 % transitioned to receiving fortified feedings (breastmilk, formula, or a combination) by 6 months of age to reverse the downward trajectory of their growth curves. Fortified feedings accelerated catch-up growth to normal weight-for-age (0.12 ± 0.80 z-score) and near normal height-for-age (-0.13 ± 0.90 z-score) at 3 years of age. Within the fortified group, breastmilk and formula were similarly effective in promoting catch-up growth, but proportionately fewer infants with CF fed predominantly breastmilk (30 %) experienced severe or moderate early-onset lung disease compared to those fed predominantly formula (62 %), p = 0.02.

CONCLUSIONS

Most infants with CF require fortified feedings to recuperate from growth faltering and achieve normal growth at 3 years of age. For these infants, the proactive/preventive strategy of fortified breastmilk feedings starting soon after CF diagnosis, an alternative to the reactive/monitoring approach, can minimize the risk of prolonged postnatal growth faltering, accelerate the potential of attaining catch-up growth, and decrease the likelihood of experiencing more severe early-onset lung disease.

Update on advances in cystic fibrosis towards a cure and implications for primary care clinicians

During the past quarter century, the diagnosis and treatment of cystic fibrosis (CF) have been transformed by molecular sciences that initiated a new era with discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The knowledge gained from that breakthrough has had dramatic clinical impact. Although once a diagnostic dilemma with long delays, preventable deaths, and irreversible pathology, CF can now be routinely diagnosed shortly after birth through newborn screening programs. This strategy of pre-symptomatic identification has eliminated the common diagnostic "odyssey" that was a failure of the healthcare delivery system causing psychologically traumatic experiences for parents. Therapeutic advances of many kinds have culminated in CFTR modulator treatment that can reduce the effects of or even correct the molecular defect in the chloride channel -the basic cause of CF. This astonishing advance has transformed CF care as described fully herein. Despite this impressive progress, there are challenges and controversies in the delivery of care. Issues include how best to achieve high sensitivity newborn screening with acceptable specificity; what course of action is appropriate for children who are identified through the unavoidable incidental findings of screening tests (CFSPID/CRMS cases and heterozygote carriers); how best to ensure genetic counseling; when to initiate the very expensive but life-saving CFTR modulator drugs; how to identify new CFTR modulator drugs for patients with non-responsive CFTR variants; how to adjust other therapeutic modalities; and how to best partner with primary care clinicians. Progress always brings new challenges, and this has been evident worldwide for CF. Consequently, this article summarizes the major advances of recent years along with controversies and describes their implications with an international perspective.

Prebiotics for people with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a multisystem disease; the importance of growth and nutritional status is well established given their implications for lung function and overall survivability. Furthermore, it has been established that intestinal microbial imbalance and inflammation are present in people with CF. Oral prebiotics are commercially available substrates that are selectively utilised by host intestinal micro-organisms and may improve both intestinal and overall health.

OBJECTIVES

To evaluate the benefits and harms of prebiotics for improving health outcomes in children and adults with CF.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews. Date of last search: 19 October 2022. We also searched PubMed and online trials registries. Date of last search: 13 January 2023.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs assessing the efficacy of prebiotics in children and adults with CF. We planned to only include the first treatment period from cross-over RCTs, regardless of washout period.

DATA COLLECTION AND ANALYSIS

We did not identify any relevant trials.

MAIN RESULTS

We did not identify any relevant trials for inclusion in this review.

AUTHORS' CONCLUSIONS

This review did not find any evidence for the use of prebiotics in people with CF. Until such evidence is available, it is reasonable for clinicians to follow any local guidelines and to discuss the use of dietary prebiotics with their patients. Large and robust RCTs assessing the dietary prebiotics of inulin or galacto-oligosaccharides or fructo-oligosaccharides, or any combination of these, are needed. Such studies should be of at least 12 months in duration and assess outcomes such as growth and nutrition, gastrointestinal symptoms, pulmonary exacerbations, lung function, inflammatory biomarkers, hospitalisations, intestinal microbial profiling, and faecal short-chain fatty acids. Trials should include both children and adults and aim to be adequately powered to allow for subgroup analysis by age.

Cystic Fibrosis-Related Gut Dysbiosis: A Systematic Review

BACKGROUND AND AIMS

Cystic Fibrosis (CF) is associated with gut dysbiosis, local and systemic inflammation, and impaired immune function. Gut microbiota dysbiosis results from changes in the complex gut milieu in response to CF transmembrane conductance regulator (CFTR) dysfunction, pancreatic malabsorption, diet, medications, and environmental influences. In several diseases, alteration of the gut microbiota influences local and systemic inflammation and disease outcomes. We conducted a systematic review of the gut microbiota in CF and explored factors influencing dysbiosis.

METHODS

An electronic search of three databases was conducted in January 2019, and re-run in June 2021. Human, animal, and in vitro studies were included. The primary outcome was differences in the gut microbiota between people with CF (pwCF) and healthy controls. Secondary outcomes included the relationship between the gut microbiota and other factors, including diet, medication, inflammation, and pulmonary function in pwCF.

RESULTS

Thirty-eight studies were identified. The literature confirmed the presence of CF-related gut dysbiosis, characterized by reduced diversity and several taxonomic changes. There was a relative increase of bacteria associated with a pro-inflammatory response coupled with a reduction of those considered anti-inflammatory. However, studies linking gut dysbiosis to systemic and lung inflammation were limited. Causes of gut dysbiosis were multifactorial, and findings were variable. Data on the impact of CFTR modulators on the gut microbiota were limited.

CONCLUSIONS

CF-related gut dysbiosis is evident in pwCF. Whether this influences local and systemic disease and is amenable to interventions with diet and drugs, such as CFTR modulators, requires further investigation.

Prebiotics for people with cystic fibrosis

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To evaluate the benefits and harms of prebiotics for improving health outcomes in children and adults with CF.

Psychosocial Issues Related to Newborn Screening: A Systematic Review and Synthesis

Genomic advances have contributed to a proliferation of newborn screening (NBS) programs. Psychosocial consequences of NBS have been identified as risks to these public health initiatives. Following PRISMA guidelines, this systematic review synthesizes findings from 92 evidence-based, peer-reviewed research reports published from 2000 through 2020 regarding psychosocial issues associated with NBS. Results describe parents' knowledge of and attitudes towards NBS, reactions to and understanding of positive NBS results, experiences of communication with health providers, decisions about carrier testing, and future pregnancies. Findings also explain the impact of positive NBS results on parent-child relationships, child development, informing children about carrier status, family burden, quality of life, and disparities. In conclusion, psychosocial consequences of receiving unexpected neonatal screening results and unsolicited genetic information remain significant risks to expansion of NBS. Findings suggest that risks may be mitigated by improved parent NBS education, effective communication, individualized genetic counseling, and anticipatory developmental guidance. Clinicians need to take extra measures to ensure equitable service delivery to marginalized subpopulations. Future investigations should be more inclusive of culturally and socioeconomically diverse families and conducted in low-resource countries. Providing these countries with adequate resources to develop NBS programs is an essential step towards achieving international health equity.

Breastfeeding in Cystic Fibrosis: A Systematic Review on Prevalence and Potential Benefits

Breastfeeding (BF) is considered the normative standard of feeding for all infants. However, the impact of BF in patients with cystic fibrosis (CF) is not completely defined. Therefore, we conducted a systematic review to evaluate BF prevalence in the CF population and its impact on anthropometric and pulmonary outcomes. We searched MEDLINE, Embase and the Cochrane Library for original articles published in English up to 4 December 2020 that report the prevalence of BF and/or any measure of association between BF and anthropometric or pulmonary outcomes. Nine observational studies were identified (six retrospective cohort studies, one prospective cohort study, one survey and one case–control study within a retrospective cohort). The BF rate in CF patients is lower than that of the healthy population (approximately 50–60% of infants were breastfed at any time). The benefits in anthropometric outcomes of BF for >2 months in this at-risk population are unclear. A few relatively small studies suggest a potential benefit of BF in reducing lung infections, although data are inconsistent. The currently available data are insufficient to draw definite conclusions on the benefits of exclusive BF in anthropometric and pulmonary outcomes in CF. Clinical trials evaluating well-defined BF promotion interventions are needed.

Academy of Nutrition and Dietetics: 2020 Cystic Fibrosis Evidence Analysis Center Evidence-Based Nutrition Practice Guideline

The Academy of Nutrition and Dietetics Evidence Analysis Center conducted a systematic review of the literature to develop an evidence-based practice guideline for primary nutrition issues in cystic fibrosis (CF). This guideline is designed to complement and build upon existing evidence-based CF nutrition guidelines. The objective of this guideline was to provide recommendations for registered dietitian nutritionists in the United States delivering medical nutrition therapy to individuals with CF and their families that fill gaps in current evidence-based guidelines on topics that are crucial in order to improve health and prevent disease progression. This guideline provides 28 nutrition recommendations to guide medical nutrition therapy, including nutrition screening, nutrition assessment, and dietary intake. For topics outside the scope of this guideline, practitioners are referred to external, evidence-based recommendations. The CF landscape is evolving rapidly with breakthroughs in cystic fibrosis transmembrane regulator modulators changing CF at a cellular level. Medical nutrition therapy for individuals with CF from infancy through advanced age requires novel and individualized approaches. The Academy Evidence Analysis Library CF guidelines provide a framework for expanding upon current knowledge to determine effective nutrition strategies for individuals with CF through long and healthy futures.

Perinatal Reduced Blood Concentrations of Free Carnitine and Acylcarnitines in Infants with Cystic Fibrosis

OBJECTIVE

Cystic fibrosis (CF) is a multisystemic inherited disease. The aim of this study was to determine free carnitine (FC) and acylcarnitine concentrations in CF newborns with various mutations of the CFTR gene perinatally.

STUDY DESIGN

FC/acylcarnitines were determined in dried blood spots via liquid chromatography-tandem mass spectrometry (LC-MS/MS) on the third day of life of full-term normal (n = 50) and CF (n = 28) newborns. For infants with elevated immunoreactive trypsinogen values, FC/acylcarnitines were quantified again 48 hours later, followed by mutational analysis of CFTR gene via Sanger sequencing.

RESULTS

Initial FC and sums of acylcarnitine concentrations were statistically significantly lower in CF patients than in controls and even lower 48 hours later. The mutations F508del and 621 + 1G > T were predominantly identified among CF patients.

CONCLUSION

Low FC and acylcarnitine concentrations were measured perinatally in CF patients, for all CFTR mutations detected. Carnitine supplementation of breastfeeding mothers could be beneficial.

Probiotics for people with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a multisystem disease and the importance of growth and nutrition has been well established, given its implications for lung function and overall survival. It has been established that intestinal dysbiosis (i.e. microbial imbalance) and inflammation is present in people with CF. Probiotics are commercially available (over-the-counter) and may improve both intestinal and overall health.

OBJECTIVES

To assess the efficacy and safety of probiotics for improving health outcomes in children and adults with CF.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of last register search: 20 January 2020. We also searched ongoing trials registries and the reference lists of relevant articles and reviews. Date of last search: 29 January 2019.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials (RCTs) assessing efficacies and safety of probiotics in children and adults with CF. Cross-over RCTs with a washout phase were included and for those without a washout period, only the first phase of each trial was analysed.

DATA COLLECTION AND ANALYSIS

We independently extracted data and assessed the risk of bias of the included trials; we used GRADE to assess the certainty of the evidence. We contacted trial authors for additional data. Meta-analyses were undertaken on outcomes at several time points.

MAIN RESULTS

We identified 17 trials and included 12 RCTs (11 completed and one trial protocol - this trial was terminated early) (464 participants). Eight trials included only children, whilst four trials included both children and adults. Trial duration ranged from one to 12 months. Nine trials compared a probiotic (seven single strain and three multistrain preparations) with a placebo preparation, two trials compared a synbiotic (multistrain) with a placebo preparation and one trial compared two probiotic preparations. Overall we judged the risk of bias in the 12 trials to be low. Three trials had a high risk of performance bias, two trials a high risk of attrition bias and six trials a high risk of reporting bias. Only two trials were judged to have low or unclear risk of bias for all domains. Four trials were sponsored by grants only, two trials by industry only, two trials by both grants and industry and three trials had an unknown funding source. Combined data from four trials (225 participants) suggested probiotics may reduce the number of pulmonary exacerbations during a four to 12 month time-frame, mean difference (MD) -0.32 episodes per participant (95% confidence interval (CI) -0.68 to 0.03; P = 0.07) (low-certainty evidence); however, the 95% CI includes the possibility of both an increased and a reduced number of exacerbations. Additionally, two trials (127 participants) found no evidence of an effect on the duration of antibiotic therapy during the same time period. Combined data from four trials (177 participants) demonstrated probiotics may reduce faecal calprotectin, MD -47.4 µg/g (95% CI -93.28 to -1.54; P = 0.04) (low-certainty evidence), but the results for other biomarkers mainly did not show any difference between probiotics and placebo. Two trials (91 participants) found no evidence of effect on height, weight or body mass index (low-certainty evidence). Combined data from five trials (284 participants) suggested there was no difference in lung function (forced expiratory volume at one second (FEV₁) % predicted) during a three- to 12-month time frame, MD 1.36% (95% CI -1.20 to 3.91; P = 0.30) (low-certainty evidence). Combined data from two trials (115 participants) suggested there was no difference in hospitalisation rates during a three- to 12-month time frame, MD -0.44 admissions per participant (95% CI -1.41 to 0.54; P = 0.38) (low-certainty evidence). One trial (37 participants) reported health-related quality of life and while the parent report favoured probiotics, SMD 0.87 (95% CI 0.19 to 1.55) the child self-report did not identify any effect, SMD 0.59 (95% CI -0.07 to 1.26) (low-certainty evidence). There were limited results for gastrointestinal symptoms and intestinal microbial profile which were not analysable. Only four trials and one trial protocol (298 participants) reported adverse events as a priori hypotheses. No trials reported any deaths. One terminated trial (12 participants and available as a protocol only) reported a severe allergic reaction (severe urticaria) for one participant in the probiotic group. Two trials reported a single adverse event each (vomiting in one child and diarrhoea in one child). The estimated number needed to harm for any adverse reaction (serious or not) is 52 people (low-certainty evidence).

AUTHORS' CONCLUSIONS

Probiotics significantly reduce faecal calprotectin (a marker of intestinal inflammation) in children and adults with CF, however the clinical implications of this require further investigation. Probiotics may make little or no difference to pulmonary exacerbation rates, however, further evidence is required before firm conclusions can be made. Probiotics are associated with a small number of adverse events including vomiting, diarrhoea and allergic reactions. In children and adults with CF, probiotics may be considered by patients and their healthcare providers. Given the variability of probiotic composition and dosage, further adequately-powered multicentre RCTs of at least 12 months duration are required to best assess the efficacy and safety of probiotics for children and adults with CF.

Lactation Consultation Sustains Breast Milk Intake in Infants With Cystic Fibrosis

Guidelines recommend breastfeeding in cystic fibrosis (CF) but breastfeeding rates decline rapidly in CF. We initiated a quality improvement project to improve breastfeeding in CF by incorporating International Board-Certified Lactation Consultants (IBCLC) into the initial CF-diagnosis visit to support mothers who were breastfeeding at diagnosis. In the preintervention group, only 8/14 (57%) continued to provide breast milk after the first visit, whereas postintervention, 16/17 (94%) mothers continued to do so (P = 0.03). The duration of any (or partial) breastfeeding increased to an average of 7.7 months from an average of 6.4 months preintervention (P = 0.45). The weight z score and weight-for-length z score at diagnosis showed no change at 6 or 12 months (all comparisons P value >0.05). We conclude that mothers who met with the IBCLC were less likely to quit breastfeeding and hypothesize that lactation support to mothers can prolong the duration of breastfeeding in infants with CF.

Nutrition: Prevention and management of nutritional failure in Cystic Fibrosis

Close monitoring of nutritional status is critical to the overall health of a patient with CF. As part of routine CF care, measurement of weight and height (and calculation of weight/length or BMI as appropriate) should be performed and analyzed at each visit. Early recognition of nutritional risk is imperative and evaluation with a multidisciplinary team should be performed to assess for caloric intake, caloric malabsorption, and other causes of poor weight gain and growth. Many tools are available to use for intervention, including oral supplementation, behavioral interventions, medications, nutritional therapies, and enteral tube feeding.

Nutritional Status in the First 2 Years of Life in Cystic Fibrosis Diagnosed by Newborn Screening

OBJECTIVE

To evaluate nutritional status and associated factors in a cystic fibrosis (CF) cohort diagnosed by newborn screening and followed up to month 24.

METHODS

A prospective longitudinal multicenter study assessing nutritional status according to pancreatic status, feeding modalities, prescriptions, pulmonary outcome, and biological nutritional parameters.

RESULTS

One hundred and five infants were recruited and 99 completed the study. Nutritional care management prevented undernutrition and stunting in those with exocrine pancreatic sufficiency (EPS), but affected (13/87) 15% and (21/86) 24%, respectively, of infants with exocrine pancreatic insufficiency (EPI). The logistic regression model found a positive association between both weight and length z scores "at risk" at month 24, and initial pulmonary symptoms (odds ratio [OR] 0.06, P < 0.01 and OR 0.08, P < 0.01, respectively); these symptoms were less frequent when age at first visit was earlier than 1.2 months (33% vs 67%, P = 0.02); stunting was also associated with high-calorie density intake and Staphylococcus aureus (OR 0.05, P = 0.01 and OR 0.17, P < 0.01). Pulmonary outcome did not differ according to pancreatic status; breast-feeding for at least 3 months delayed first acquisition of Pseudomonas aeruginosa. Despite sodium and fat-soluble vitamin supplementation, half of both cohorts had low urinary sodium output and half of the EPI cohort had low vitamin D levels.

CONCLUSIONS

Our data shed light on the fact that stunting was more frequent than undernutrition, while both parameters involved only patients with pancreatic insufficiency. Modalities of feeding were not associated with nutritional status; breast-feeding may provide some protection against acquisition of P aeruginosa.

[Liver disease, gastrointestinal complications, nutritional management and feeding disorders in pediatric cystic fibrosis]

In cystic fibrosis (CF), approximately 5-8% of the patients develop multilobular cirrhosis during the first decade of life. Annual screening (clinical examination, liver biochemistry, ultrasonography) is recommended in order to identify early signs of liver involvement, initiate ursodeoxycholic acid therapy and detect complications (portal hypertension and liver failure). Management should focus on nutrition and prevention of variceal bleeding. The gut may also be involved in children with CF. Gastroesophageal reflux is frequent, although often neglected and should be investigated by pH monitoring and impedancemetry, if available. Acute pancreatitis occurs in patients with persistent exocrine pancreatic activity. Intussusception, appendicular mucocele, distal intestinal occlusion syndrome, small bowel bacterial overgrowth and Clostridium difficile colitis should be considered in case of abdominal pain. Preventive nutritional support should be started as soon as possible after diagnosis of CF. Attainment of normal growth is one of the main goals and can be achieved with hypercaloric and salt supplemented food. Pancreatic enzyme replacement therapy should be started as soon as exocrine pancreatic insufficiency is confirmed and ingested immediately prior to meals with intake of fat-soluble vitamins. Curative nutritional interventions are more likely to be effective in the early stages of pulmonary disease. Feeding disorders, related to the physiopathology and the psychologic aspects of the disease are frequent. Repeated corporeal aggressions, associated with inappropriate medical and parental pressure, may increase the child's refusal of food. The multidisciplinary team should guide parents in order to avoid all intrusive feeding practices and promote pleasant mealtimes.

Zystische Fibrose

Die zystische Fibrose (Synonym: Mukoviszidose) ist auch heute noch eine unheilbare, letal verlaufende Krankheit. Durch die fortlaufende Verbesserung der Therapie ist es in den vergangenen Jahren gelungen, Lebenserwartung und Lebensqualität deutlich zu verbessern. Im Rahmen der Multisystemerkrankung finden sich im Gastrointestinaltrakt wichtige Manifestationen (an Pankreas, Dünndarm, Leber und Gallenwegen), die mit der auch heute noch prognostisch ungünstigen, aber häufig vorkommenden Ernährungsstörung zusammengehen. Frühdiagnose und Frühtherapie können das Auftreten von Komplikationen verhindern bzw. hinauszögern. Neueste Daten zeigen, dass eine mutationsspezifische pharmakologische Therapie auf Ionenkanalebene wirksam ist. Die konventionelle, zentrumorientierte und qualitätsgesicherte Behandlung der zystischen Fibrose erfordert den integrierten Einsatz der pädiatrischen Gastroenterologie.

Newborn screening for cystic fibrosis

PURPOSE OF REVIEW

Newborn screening for cystic fibrosis (CF) is now universal in the US and many other countries. The rapid expansion of screening has resulted in numerous publications identifying new challenges for healthcare providers. This review provides an overview of these publications and includes ideas on managing these challenges.

RECENT FINDINGS

Most CF newborn screening algorithms involve DNA mutation analysis. As screening has expanded, new challenges have been identified related to carrier detection and inconclusive diagnoses. Early descriptions of infants with CF-related metabolic syndrome (CRMS) indicate that the natural history of this condition cannot be predicted. Early identification has also provided an opportunity to better understand the pathophysiology of CF. However, few studies have been conducted in infants with CF to determine optimal therapy and recommendations are largely anecdotal.

SUMMARY

Newborn screening provides an opportunity to identify and begin treatment early in individuals with CF. Whereas a single, optimal approach to screening does not exist, all programs can benefit from new findings regarding sweat testing, carrier detection, early pathophysiology, and clinical outcomes.