Survival effect of lung transplantation among patients with cystic fibrosis

Diagnosis and Management of Cystic Fibrosis Exacerbations

With the improving survival of cystic fibrosis (CF) patients and the advent of highly effective cystic fibrosis transmembrane conductance regulator (CFTR) therapy, the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is acute pulmonary exacerbation (PEx). Clinical and microbial epidemiology studies of CF PEx continue to provide important insight into the disease course, prognosis, and complications. This work has now led to several large-scale clinical trials designed to clarify the treatment paradigm for CF PEx. The primary goal of this review is to provide a summary and update of the pathophysiology, clinical and microbial epidemiology, outcome and treatment of CF PEx, biomarkers for exacerbation, and the impact of highly effective modulator therapy on these events moving forward.

A Value-of-Information Framework for Personalizing the Timing of Surveillance Testing

BACKGROUND

Patient surveillance using repeated biomarker measurements presents an opportunity to detect and treat disease progression early. Frequent surveillance testing using biomarkers is recommended and routinely conducted in several diseases, including cancer and diabetes. However, frequent testing involves tradeoffs. Although surveillance tests provide information about current disease status, the complications and costs of frequent tests may not be justified for patients who are at low risk of progression. Predictions based on patients' earlier biomarker values may be used to inform decision making; however, predictions are uncertain, leading to decision uncertainty.

METHODS

We propose the Personalized Risk-Adaptive Surveillance (PRAISE) framework, a novel method for embedding predictions into a value-of-information (VOI) framework to account for the cost of uncertainty over time and determine the time point at which collection of biomarker data would be most valuable. The proposed sequential decision-making framework is innovative in that it leverages the patient's longitudinal history, considers individual benefits and harms, and allows for dynamic tailoring of surveillance intervals by considering the uncertainty in current information and estimating the probability that new information may change treatment decisions, as well as the impact of this change on patient outcomes.

RESULTS

When applied to data from cystic fibrosis patients, PRAISE lowers costs by allowing some patients to skip a visit, compared to an "always test" strategy. It does so without compromising expected survival, by recommending less frequent testing among those who are unlikely to be treated at the skipped time point.

CONCLUSIONS

A VOI-based approach to patient monitoring is feasible and could be applied to several diseases to develop more cost-effective and personalized strategies for ongoing patient care.

HIGHLIGHTS

In many patient-monitoring settings, the complications and costs of frequent tests are not justified for patients who are at low risk of disease progression. Predictions based on patient history may be used to individualize the timing of patient visits based on evolving risk.We propose Personalized Risk-Adaptive Surveillance (PRAISE), a novel method for personalizing the timing of surveillance testing, where prediction modeling projects the disease trajectory and a value-of-information (VOI)-based pragmatic decision-theoretic framework quantifies patient- and time-specific benefit-harm tradeoffs.A VOI-based approach to patient monitoring could be applied to several diseases to develop more personalized and cost-effective strategies for ongoing patient care.

Recipient Age Impacts Long-Term Survival in Adult Subjects with Cystic Fibrosis after Lung Transplantation

Rationale: Lung transplant is an effective treatment option providing survival benefit in patients with cystic fibrosis (CF). Several studies have suggested survival benefit in adults compared with pediatric patients with CF undergoing lung transplant. However, it remains unclear whether this age-related disparity persists in adult subjects with CF.Objectives: We investigated the impact of age at transplant on post-transplant outcomes in adult patients with CF.Methods: The United Network of Organ Sharing Registry was queried for all adult patients with CF who underwent lung transplantation between 1992 and 2016. Pertinent baseline characteristics, demographics, clinical parameters, and outcomes were recorded. The patients were divided into two groups based on age at transplant (18-29 yr old and 30 yr or older). The primary endpoint was survival time. Assessment of post-transplant survival was performed using Kaplan-Meier tests and log-rank tests with multivariable Cox proportional hazards analysis to adjust for confounding variables.Results: A total of 3,881 patients with CF underwent lung transplantation between 1992 and 2016; mean age was 31.0 (± 9.3) years. The 18-29-year-old at transplant cohort consisted of 2,002 subjects and the 30 years or older cohort had 1,879 subjects. Survival analysis demonstrated significantly higher survival in subjects in the 30 years or older cohort (9.47 yr; 95% confidence interval [CI], 8.7-10.2) compared with the 18-29-year-old cohort (5.21 yr; 95% CI, 4.6-5.8). After adjusting for confounders, survival remained higher in recipients aged 30 years or older (hazard ratio, 0.44; 95% CI, 0.2-0.9). Mortality due to allograft failure was significantly lower in patients with CF aged 30 years or older (28% vs. 36.5%; odds ratio [OR], 0.7; 95% CI, 0.6-0.8), whereas the incidence of malignancy was higher in the 30 years or older cohort (8% vs. 2.9%; OR, 3.0; 95% CI, 1.9-4.6).Conclusions: Age at transplant influences lung transplant outcomes in recipients with CF. Subjects with CF aged 30 years or older at transplant have superior survival compared with adult subjects with CF transplanted between the ages 18 and 29 years.

Clinical characteristics and outcomes in adult cystic fibrosis patients with severe lung disease in Porto Alegre, southern Brazil

Background

Advanced lung disease in adult cystic fibrosis (CF) drives most clinical care requirements. The aim was to evaluate outcome (time to death while in the study) in a cohort of adult CF patients with severe lung disease, and to determine the association among baseline patient characteristics and outcome.

Methods

A retrospective cohort study was performed and clinical records between 2000 and 2015 were reviewed. Severe lung disease was defined as forced expiratory volume in the first second (FEV₁) < 30% of predicted. Outcomes of all patients, including their date of death or transplantation, were determined till January 1st, 2016. Clinical data were recorded at the entry date.

Results

Among 39 subjects included in the study, 20 (51.3%) died, 16 (41.0%) underwent bilateral lung transplantation, and 3 were alive at the end of the study period. Two variables were independently associated with death: body mass index (BMI ≥ 18.5 kg/m²) (HR = 0.78, 95% CI = 0.64–0.96 and p = 0.017) and use of tobramycin inhalation therapy (HR = 3.82, 95% CI = 1.38–10.6 and p = 0.010). Median survival was 37 (95% CI = 16.4–57.6) months. The best cut-off point for BMI was 18.5 kg/m². Median survival in patients with BMI < 18.5 kg/m² was 36 months (95% CI = 18.7–53.3).

Conclusion

Median survival of CF subjects with FEV₁ < 30% was 37 months. BMI and tobramycin inhalation therapy were independently associated with death. Median survival in patients with BMI < 18.5 kg/m² was significantly lower than in patients with BMI ≥ 18.5 kg/m². The association of tobramycin inhalation with death was interpreted as confounding by severity (use was reserved for advanced lung disease).

Evaluation of a five-year predicted survival model for cystic fibrosis in later time periods

We evaluated a multivariable logistic regression model predicting 5-year survival derived from a 1993-1997 cohort from the United States Cystic Fibrosis (CF) Foundation Patient Registry to assess whether therapies introduced since 1993 have altered applicability in cohorts, non-overlapping in time, from 1993-1998, 1999-2004, 2005-2010 and 2011-2016. We applied Kaplan-Meier statistics to assess unadjusted survival. We tested logistic regression model discrimination using the C-index and calibration using Hosmer-Lemeshow tests to examine original model performance and guide updating as needed. Kaplan-Meier age-adjusted 5-year probability of death in the CF population decreased substantially during 1993-2016. Patients in successive cohorts were generally healthier at entry, with higher average age, weight and lung function and fewer pulmonary exacerbations annually. CF-related diabetes prevalence, however, steadily increased. Newly derived multivariable logistic regression models for 5-year survival in new cohorts had similar estimated coefficients to the originals. The original model exhibited excellent calibration and discrimination when applied to later cohorts despite improved survival and remains useful for predicting 5-year survival. All models may be used to stratify patients for new studies, and the original coefficients may be useful as a baseline to search for additional but rare events that affect survival in CF.

Antioxidant Micronutrients and Essential Fatty Acids Supplementation on Cystic Fibrosis Outcomes: A Systematic Review

BACKGROUND

Antioxidant micronutrients and essential fatty acids supplementation intake appears to have a protective effect in some diseases such as cardiovascular disease, cancer, and asthma.

OBJECTIVE

The aim of this study was to perform a systematic review to evaluate the effects of these nutrients on nutritional and clinical outcomes of patients with cystic fibrosis (CF).

METHODS

This is a systematic review of randomized clinical trials (RCTs) in CF. MEDLINE (via PubMed), Embase, and Scopus databases were searched for RCTs published from 1948 through February 2019. Two investigators independently reviewed the titles and abstracts and then extracted the data from the included studies using a standardized predesigned form. Two reviewers independently performed the quality assessment of the RCTs according to the Cochrane risk of bias tools.

RESULTS

A total of 4,792 studies were identified, and 23 were eligible (8 antioxidant micronutrient and 15 essential fatty acids). The interventions found were beta-carotene, zinc, magnesium, multivitamin, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), linoleic acid and lipid matrix with choline supplementation. A significant improvement was observed in: (a) pulmonary function with magnesium (n=1) and essential fatty acids (n=2) supplementation; (b) less pulmonary exacerbations with beta-carotene (n=1), zinc (n=1), antioxidant-enriched multivitamin (n=1) and essential fatty acids (n=2) supplementation. One study with antioxidant-enriched multivitamin and four studies with EPA/DHA supplementation reported significant reductions in inflammatory markers. Nutritional status was not modified by antioxidants supplementation in any of the studies, while in five studies there was an improvement with fatty acids supplementation. The risk of bias of the majority of the parallel studies was high.

CONCLUSIONS

The benefits of antioxidants or DHA/EPA supplementation for CF, although observed in some studies, are not consistent enough to recommend routine use of these supplements. The mechanisms of action of these nutrients, dose levels and timing should be further explored in future studies.

Timing it right: the challenge of recipient selection for lung transplantation

Selection criteria for the referral and potential listing of patients for lung transplantation (LTx) have changed considerably over the last three decades but one key maxim prevails, the ultimate focus is to increase longevity and quality of life by careful utilization of a rare and precious resource, the donor organs. In this article, we review how the changes have developed and the outcomes of those changes, highlighting the impact of the lung allocation score (LAS) system. Major diseases, including interstitial lung disease (ILD), chronic obstructive pulmonary disease and pulmonary hypertension are considered in detail as well as the concept of retransplantation where appropriate. Results from bridging to LTx using extracorporeal membrane oxygenation (ECMO) are discussed and other potential contraindications evaluated such as advanced age, frailty and resistant infections. Given the multiplicity of risk factors it is a credit to those working in the field that such excellent and improving results are obtained with an ongoing dedication to achieving best practice.

Acute Pulmonary Exacerbations in Cystic Fibrosis

With the improving survival of cystic fibrosis (CF) patients and the advent of highly effective cystic fibrosis transmembrane conductance regulator therapy, the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is an acute pulmonary exacerbation. Clinical and microbial epidemiology studies of CF pulmonary exacerbations continue to provide important insight into the disease course, prognosis, and complications. This work has now led to a number of large scale clinical trials with the goal of improving the treatment paradigm for CF pulmonary exacerbation. The primary goal of this review is to provide a summary of the pathophysiology, the clinical epidemiology, microbial epidemiology, outcome and the treatment of CF pulmonary exacerbation.

Outcomes of Lung Transplantation for Cystic Fibrosis in the Setting of Extensively Drug-Resistant Organisms

Introduction:

Since the largest study on extensively drug-resistant organisms and lung transplantation in patients with cystic fibrosis, there have been innovations and advancements in the treatment of Pseudomonas aeruginosa.

Research Question:

What differences exist for patients with cystic fibrosis with a history of extensively drug-resistant infections who undergo lung transplantation despite treatment advances with antimicrobial therapy?

Study Design:

Two-center, retrospective, cohort study conducted in 44 patients with cystic fibrosis chronically infected with extensively drug-resistant organisms who received a lung transplant from January 2008 through August 2016. Patients in the resistant cohort were chronically infected with pan-resistant P aeruginosa, polymyxin-sensitive only, or sensitive to 2 antibiotic classes (polymyxin plus one other); remaining patients with more susceptible P aeruginosa or no P aeruginosa remained in the control cohort. The primary outcome is a composite of patient survival, retransplantation, chronic lung allograft dysfunction, and acute rejection 12 months posttransplant. Categorical variables were analyzed using χ2 testing. The independent samples t test was utilized for continuous variables.

Results:

There was no difference in the primary outcome (40% vs 37%, P = .831). Differences between patient survival (84% vs 95%, P = .487), the incidence of acute rejection (20% vs 33%, P = .323), and the incidence of chronic lung allograft rejection (12% vs 5%, P = .441) were not different between groups.

Discussion:

Recipients chronically infected with an extensively resistant P aeruginosa had similar outcomes compared to those infected with more sensitive organisms.

Dynamic-DeepHit: A Deep Learning Approach for Dynamic Survival Analysis With Competing Risks Based on Longitudinal Data

Currently available risk prediction methods are limited in their ability to deal with complex, heterogeneous, and longitudinal data such as that available in primary care records, or in their ability to deal with multiple competing risks. This paper develops a novel deep learning approach that is able to successfully address current limitations of standard statistical approaches such as landmarking and joint modeling. Our approach, which we call Dynamic-DeepHit, flexibly incorporates the available longitudinal data comprising various repeated measurements (rather than only the last available measurements) in order to issue dynamically updated survival predictions for one or multiple competing risk(s). Dynamic-DeepHit learns the time-to-event distributions without the need to make any assumptions about the underlying stochastic models for the longitudinal and the time-to-event processes. Thus, unlike existing works in statistics, our method is able to learn data-driven associations between the longitudinal data and the various associated risks without underlying model specifications. We demonstrate the power of our approach by applying it to a real-world longitudinal dataset from the U.K. Cystic Fibrosis Registry, which includes a heterogeneous cohort of 5883 adult patients with annual follow-ups between 2009 to 2015. The results show that Dynamic-DeepHit provides a drastic improvement in discriminating individual risks of different forms of failures due to cystic fibrosis. Furthermore, our analysis utilizes post-processing statistics that provide clinical insight by measuring the influence of each covariate on risk predictions and the temporal importance of longitudinal measurements, thereby enabling us to identify covariates that are influential for different competing risks.

Linaclotide improves gastrointestinal transit in cystic fibrosis mice by inhibiting sodium/hydrogen exchanger 3

Gastrointestinal dysfunction in cystic fibrosis (CF) is a prominent source of pain among patients with CF. Linaclotide, a guanylate cyclase C (GCC) receptor agonist, is a US Food and Drug Administration-approved drug prescribed for chronic constipation but has not been widely used in CF, as the cystic fibrosis transmembrane conductance regulator (CFTR) is the main mechanism of action. However, anecdotal clinical evidence suggests that linaclotide may be effective for treating some gastrointestinal symptoms in CF. The goal of this study was to determine the effectiveness and mechanism of linaclotide in treating CF gastrointestinal disorders using CF mouse models. Intestinal transit, chloride secretion, and intestinal lumen fluidity were assessed in wild-type and CF mouse models in response to linaclotide. CFTR and sodium/hydrogen exchanger 3 (NHE3) response to linaclotide was also evaluated. Linaclotide treatment improved intestinal transit in mice carrying either F508del or null Cftr mutations but did not induce detectable Cl^- secretion. Linaclotide increased fluid retention and fluidity of CF intestinal contents, suggesting inhibition of fluid absorption. Targeted inhibition of sodium absorption by the NHE3 inhibitor tenapanor produced improvements in gastrointestinal transit similar to those produced by linaclotide treatment, suggesting that inhibition of fluid absorption by linaclotide contributes to improved gastrointestinal transit in CF. Our results demonstrate that linaclotide improves gastrointestinal transit in CF mouse models by increasing luminal fluidity through inhibiting NHE3-mediated sodium absorption. Further studies are necessary to assess whether linaclotide could improve CF intestinal pathologies in patients. GCC signaling and NHE3 inhibition may be therapeutic targets for CF intestinal manifestations. NEW & NOTEWORTHY Linaclotide's primary mechanism of action in alleviating chronic constipation is through cystic fibrosis transmembrane conductance regulator (CFTR), negating its use in patients with cystic fibrosis (CF). For the first time, our findings suggest that in the absence of CFTR, linaclotide can improve fluidity of the intestinal lumen through the inhibition of sodium/hydrogen exchanger 3. These findings suggest that linaclotide could improve CF intestinal pathologies in patients.

Prognostication and Risk Factors for Cystic Fibrosis via Automated Machine Learning

Accurate prediction of survival for cystic fibrosis (CF) patients is instrumental in establishing the optimal timing for referring patients with terminal respiratory failure for lung transplantation (LT). Current practice considers referring patients for LT evaluation once the forced expiratory volume (FEV1) drops below 30% of its predicted nominal value. While FEV1 is indeed a strong predictor of CF-related mortality, we hypothesized that the survival behavior of CF patients exhibits a lot more heterogeneity. To this end, we developed an algorithmic framework, which we call AutoPrognosis, that leverages the power of machine learning to automate the process of constructing clinical prognostic models, and used it to build a prognostic model for CF using data from a contemporary cohort that involved 99% of the CF population in the UK. AutoPrognosis uses Bayesian optimization techniques to automate the process of configuring ensembles of machine learning pipelines, which involve imputation, feature processing, classification and calibration algorithms. Because it is automated, it can be used by clinical researchers to build prognostic models without the need for in-depth knowledge of machine learning. Our experiments revealed that the accuracy of the model learned by AutoPrognosis is superior to that of existing guidelines and other competing models.

Lung transplantation: indications and contraindications

The selection of appropriate recipients for lung transplantation is an evolving discipline. As experience with the procedure has developed over the last decades, the identification of transplant candidates has also changed as transplant centers strive to safely provide the therapy to as many patients possible. The International Society for Heart and Lung Transplantation (ISHLT) has developed three editions of recipient selection guidelines. Published in 1998, 2006, and 2015, these guidelines represented the best information relevant to the appropriate selection of lung transplant candidates. A discussion of areas supported by the most robust scientific data will be undertaken, but in many aspects of recipient selection, there is a paucity of data upon which to rely. Therefore, it is ultimately the prerogative and responsibility of individual centers to determine, after carefully weighing the best evidence available, whether a patient is deemed a suitable candidate at a specific program. All possible indications and contraindications for transplantation will be reviewed with attention also given to the appropriate timing of referral and listing of patients with advanced lung disease to a transplant center.

Mortality rate of patients with cystic fibrosis on the waiting list and within one year after lung transplantation: a survey of Italian CF centers

Background

Cystic Fibrosis (CF) Centers are involved in the decisions regarding the eligibility of CF patients with end-stage lung disease and timing for inclusion on waiting lists (WL) for lung transplantation (LT). There are currently no data on the mortality rates of Italian CF patients on WL and during the first year after LT and we aimed to assess these outcomes by surveying the CF Centers.

Methods

A survey was sent to Italian CF Centers which were requested to report the age at which all CF subjects included on the WL between 2010 and 2014 were included on the list, admitted to either standard or urgent LT, or had died either while on the WL or within the first 3 and 12 months after LT. All outcomes were recorded by December 31, 2015.

Results

Two hundred fifty-nine CF subjects were included on the WL during the 5-year study period. The mortality rate during the WL was 19.3% and was not associated with sex, age at inclusion on the WL or standard or urgent access to LT. 159 (61.4%) subjects underwent LT, 46 (28.9%) with urgent procedure. Deaths within the first 3 and 12 months after LT were significantly more prevalent in individuals who underwent urgent LT compared to those with standard LT (p < 0.01).

Conclusions

The mortality of Italian CF patients, included in our survey, was about twice that reported by the National Transplant Center for all LT indications, including CF, during the same time period and despite the introduction of urgent LT. The latter was associated with an unfavorable early outcome compared to standard LT.

ECFS best practice guidelines: the 2018 revision

Developments in managing CF continue to drive dramatic improvements in survival. As newborn screening rolls-out across Europe, CF centres are increasingly caring for cohorts of patients who have minimal lung disease on diagnosis. With the introduction of mutation-specific therapies and the prospect of truly personalised medicine, patients have the potential to enjoy good quality of life in adulthood with ever-increasing life expectancy. The landmark Standards of Care published in 2005 set out what high quality CF care is and how it can be delivered throughout Europe. This underwent a fundamental re-write in 2014, resulting in three documents; center framework, quality management and best practice guidelines. This document is a revision of the latter, updating standards for best practice in key aspects of CF care, in the context of a fast-moving and dynamic field. In continuing to give a broad overview of the standards expected for newborn screening, diagnosis, preventative treatment of lung disease, nutrition, complications, transplant/end of life care and psychological support, this consensus on best practice is expected to prove useful to clinical teams both in countries where CF care is developing and those with established CF centres. The document is an ECFS product and endorsed by the CF Network in ERN LUNG and CF Europe.

Survival Benefit of Lung Transplantation in the Modern Era of Lung Allocation

RATIONALE

Lung transplantation is an accepted and increasingly employed treatment for advanced lung diseases, but the anticipated survival benefit of lung transplantation is poorly understood.

OBJECTIVES

To determine whether and for which patients lung transplantation confers a survival benefit in the modern era of U.S. lung allocation.

METHODS

Data on 13,040 adults listed for lung transplantation between May 2005 and September 2011 were obtained from the United Network for Organ Sharing. A structural nested accelerated failure time model was used to model the survival benefit of lung transplantation over time. The effects of patient, donor, and transplant center characteristics on the relative survival benefit of transplantation were examined.

MEASUREMENTS AND MAIN RESULTS

Overall, 73.8% of transplant recipients were predicted to achieve a 2-year survival benefit with lung transplantation. The survival benefit of transplantation varied by native disease group (P = 0.062), with 2-year expected benefit in 39.2 and 98.9% of transplants occurring in those with obstructive lung disease and cystic fibrosis, respectively, and by lung allocation score at the time of transplantation (P < 0.001), with net 2-year benefit in only 6.8% of transplants occurring for lung allocation score less than 32.5 and in 99.9% of transplants for lung allocation score exceeding 40.

CONCLUSIONS

A majority of adults undergoing transplantation experience a survival benefit, with the greatest potential benefit in those with higher lung allocation scores or restrictive native lung disease or cystic fibrosis. These results provide novel information to assess the expected benefit of lung transplantation at an individual level and to enhance lung allocation policy.

Exercise performance and quality of life in children with cystic fibrosis and mildly impaired lung function: relation with antibiotic treatments and hospitalization

This study evaluates the impact of antibiotic treatments and hospitalization on exercise performance and health-related quality of life (QOL) in children with mild cystic fibrosis (CF) lung disease. Forty-seven children between 7 and 17 years with mild CF underwent a maximal exercise test including spiro-ergometry and filled out a QOL-questionnaire (PedsQL™). Amount of antibiotic treatments (AB) and hospitalization days in the last 3 years were reviewed. FEV1% was mildly decreased (91.7 ± 17.9 L/min, p = 0.02). Maximal oxygen consumption (VO₂max), test duration and anaerobic threshold were lower compared to a control population (VO₂max% 94 ± 15 vs 103 ± 13, p = 0.009). FEV1% correlated with AB and hospitalization episodes in the last year and 3 years before testing, VO₂max% only correlated with AB in the last 3 years. Domains of school functioning and emotional functioning were low. Children with higher VO₂max% and less AB in the last 3 years had better physical health. Physical health and school functioning were negatively correlated with hospitalization days in the last year.

CONCLUSION

Patients with mild CF lung disease have good exercise performance although still lower than the normal population. VO2max% is affected by number of antibiotic treatments over a longer period. There is an impact of hospitalization days on quality of life. What is Known: • Children with CF have lower exercise performance; there is an association between hospitalization frequency and exercise performance • Quality of life is diminished in children with CF and influenced by respiratory infections What is New: • Even patients with mild CF lung disease have lower maximal exercise performance (VO ₂ max) and a lower anaerobic threshold; VO ₂ max is lower in children who had more antibiotic treatments in the last 3 years • School and emotional functioning are diminished in children with mild CF lung disease; hospitalization is negatively correlated with school functioning and physical functioning.

Data that empower: The success and promise of CF patient registries

In this article, we describe existing CF registries with a focus on US registry data collected through the CF Foundation Patient Registry (CFFPR) and the Epidemiologic Study of CF (ESCF); highlight what registries have taught us regarding epidemiology of CF; showcase the impact of registries on research and clinical care; and discuss future directions. This manuscript complements the plenary address given by Dr Wayne Morgan at the 2016 North American CF Conference by summarizing the key points from the presentation and providing additional detail and information.

Outcomes after lung transplantation

With more than 50,000 procedures having been performed worldwide, lung transplantation (LT) has become the standard of care for patients with end-stage chronic respiratory failure. LT leads to dramatic improvements in both pulmonary function and health related quality of life. Survival after LTs has steadily improved, but still lags far behind that observed after other solid organ transplantations, as evidenced by a median survival rate that currently stands at 5.8 years. Because of these disappointing results, the ability of LT to expand survival has been questioned. However, the most recent studies, based on sophisticated statistical modeling suggest that LT confers a survival benefit to the vast majority of lung transplant recipients. Chronic lung allograft dysfunction (CLAD) that develops in about 50% of recipients 5 years after LT is a major impediment to lung transplant survival. A better understanding of the mechanisms underlying CLAD could allow for better post-transplant survival.

Transplantation

Despite improvement in median life expectancy and overall health, some children with cystic fibrosis (CF) progress to end-stage lung or liver disease and become candidates for transplant. Transplants for children with CF hold the promise to extend and improve the quality of life, but barriers to successful long-term outcomes include shortage of suitable donor organs; potential complications from the surgical procedure and immunosuppressants; risk of rejection and infection; and the need for lifelong, strict adherence to a complex medical regimen. This article reviews the indications and complications of lung and liver transplantation in children with CF.

A global perspective of lung transplantation: Part 1 - Recipient selection and choice of procedure

Lung transplantation has grown considerably in recent years and its availability has spread to an expanding number of countries worldwide. Importantly, survival has also steadily improved, making this an increasingly viable procedure for patients with end-stage lung disease and limited life expectancy. In this first of a series of articles, recipient selection and type of transplant operation are reviewed. Pulmonary fibrotic disorders are now the most indication in the U.S., followed by chronic obstructive pulmonary disease and cystic fibrosis. Transplant centers have liberalized criteria to include older and more critically ill candidates. A careful, systematic, multi-disciplinary selection process is critical in identifying potential barriers that may increase risk and optimize long-term outcomes.

Predictors of non-referral of patients with cystic fibrosis for lung transplant evaluation in the United States

BACKGROUND

Lung transplantation is an intervention that improves survival for adult patients with cystic fibrosis (CF). Some patients with CF are never referred for lung transplant evaluation despite meeting physiologic criteria for referral.

METHODS

We performed a retrospective analysis of adult patients (≥18years of age) in the Cystic Fibrosis Foundation Patient Registry (CFFPR), eligible for their first evaluation for lung transplantation during the years 2001-2008 based on FEV1<30% predicted in two consecutive years.

RESULTS

Within the CFFPR, 1240 patients met eligibility criteria. Eight hundred and nine (65.2%) were referred for lung transplant evaluation, and 431 (34.8%) were not referred. In a multivariable model, Medicaid insurance (OR 1.79, 95% CI 1.29-2.47), older age (per 5year increase; OR 1.25, 95% CI 1.13-1.39), lack of high school graduate education (OR 2.27, 95% CI 1.42-3.64), and Burkholderia cepacia complex sputum culture positivity (OR 2.48, 95% CI 1.50-4.12) were associated with non-referral, while number of pulmonary exacerbations (OR 0.93, 95% CI 0.87-0.99) and supplemental oxygen use (OR 0.59, 95% CI 0.43-0.81) were associated with increased referral.

CONCLUSIONS

Despite meeting lung function criteria for lung transplant evaluation, 35% of patients with CF had not yet been referred to a lung transplant center. Predictors of non-referral included markers of low socioeconomic status, older age and B. cepacia complex sputum culture. Further work is needed to understand the outcomes for non-referred patients in order to refine referral recommendations in this population.

Emerging bacterial pathogens and changing concepts of bacterial pathogenesis in cystic fibrosis

Chronic suppurative lower airway infection is a hallmark feature of cystic fibrosis (CF). Decades of experience in clinical microbiology have enabled the development of improved technologies and approaches for the cultivation and identification of microorganisms from sputum. It is increasingly apparent that the microbial constituents of the lower airways in CF exist in a dynamic state. Indeed, while changes in prevalence of various pathogens occur through ageing, differences exist in successive cohorts of patients and between clinics, regions and countries. Classical pathogens such as Pseudomonas aeruginosa, Burkholderia cepacia complex and Staphylococcus aureus are increasingly being supplemented with new and emerging organisms rarely observed in other areas of medicine. Moreover, it is now recognized that common oropharyngeal organisms, previously presumed to be benign colonizers may contribute to disease progression. As infection remains the leading cause of morbidity and mortality in CF, an understanding of the epidemiology, risk factors for acquisition and natural history of infection including interactions between colonizing bacteria is required. Unified approaches to the study and determination of pathogen status are similarly needed. Furthermore, experienced and evidence-based treatment data is necessary to optimize outcomes for individuals with CF.

Reduction in Pseudomonas aeruginosa sputum density during a cystic fibrosis pulmonary exacerbation does not predict clinical response

Background

Pulmonary exacerbations (PEx) are critical events in cystic fibrosis (CF), responsible for reduced quality of life and permanent loss of lung function. Approximately 1/4 of PEx are associated with failure to recover lung function and/or resolve symptoms. Developing tools to optimize PEx treatment is of paramount importance.

Methods

We retrospectively audited all adults infected with Pseudomonas aeruginosa, experiencing PEx necessitating parenteral antibiotic therapy from 2006–2012 from our center. Quantitative analysis of sputum at admission, twice-weekly during hospitalization, and end of therapy were compared to baseline (most recent healthy) and follow-up (after PEx) samples. Change in P. aeruginosa burden from baseline was assessed for any and all morphotypes (ALL), as well as mucoid (MUC) and non-mucoid (NON) isolates specifically. PEx were identified as failures if >90% of baseline pulmonary function was not recovered.

Results

Forty-six patients meeting the above inclusion and exclusion criteria experienced 144 PEx during this time (median 3, IQR 2–6). Patients were treated for a median 14 days (IQR 13–16). No increase in ALL, MUC or NON were detected at PEx, nor was there an association between change in sputum density and magnitude of lung function decline. PEx failures were observed in 30% of events. Reductions of at least 1-log and 2 log P. aeruginosa sputum density was observed in 57% and 46% (ALL), 73% and 55% (MUC) and 58% and 46% (NON) of PEx, respectively. Factors associated with greater reduction of P. aeruginosa sputum density included choice of β-lactam antibiotic, antibiotics with in vitro predicted activity and treatment duration. PEx associated with reductions in P. aeruginosa sputum density were not associated with a reduced risk of PEx failure.

Conclusions

Enhanced killing of P. aeruginosa during PEx does not predict improved clinical outcomes. Studies accounting for the polymicrobial nature of CF respiratory disease and the heterogeneity of P. aeruginosa causing chronic infection may enable the identification of a more appropriate pathogen(s) based biomarker of PEx outcomes.

European Cystic Fibrosis Society Standards of Care: Best Practice guidelines

Specialised CF care has led to a dramatic improvement in survival in CF: in the last four decades, well above what was seen in the general population over the same period. With the implementation of newborn screening in many European countries, centres are increasingly caring for a cohort of patients who have minimal lung disease at diagnosis and therefore have the potential to enjoy an excellent quality of life and an even greater life expectancy than was seen previously. To allow high quality care to be delivered throughout Europe, a landmark document was published in 2005 that sets standards of care. Our current document builds on this work, setting standards for best practice in key aspects of CF care. The objective of our document is to give a broad overview of the standards expected for screening, diagnosis, pre-emptive treatment of lung disease, nutrition, complications, transplant/end of life care and psychological support. For comprehensive details of clinical care of CF, references to the most up to date European Consensus Statements, Guidelines or Position Papers are provided in Table 1. We hope that this best practice document will be useful to clinical teams both in countries where CF care is developing and those with established CF centres.

A contemporary survival analysis of individuals with cystic fibrosis: a cohort study

Previously established predictors of survival may no longer apply in the current era of cystic fibrosis (CF) care. Our objective was to identify risk factors associated with survival in a contemporary CF population.

We used the Canadian CF Registry, a population-based cohort, to calculate median age of survival and summarise patient characteristics from 1990 to 2012. Clinical, demographic and geographical factors, and survival were estimated for a contemporary cohort (2000–2012) using Cox proportional hazards models.

There were 5787 individuals in the registry between 1990 and 2012. Median survival age increased from 31.9 years (95% CI 28.3–35.2 years) in 1990 to 49.7 years (95% CI 46.1–52.2 years) in the most current 5-year window ending in 2012. Median forced expiratory volume in 1 s improved (p=0.04) and fewer subjects were malnourished (p<0.001) over time. Malnourished patients (hazard ratio (HR) 2.1, 95% CI 1.6–2.8), those with multiple exacerbations (HR 4.5, 95% CI 3.2–6.4) and women with CF-related diabetes (HR 1.8, 95% CI 1.2–2.7) were at increased risk of death.

Life expectancy in Canadians with CF is increasing. Modifiable risk factors such as malnutrition and pulmonary exacerbations are associated with an increased risk of death. The sex gap in CF survival may be explained by an increased hazard for death in women with CF-related diabetes.

Update in lung transplantation 2013

Research in pulmonary transplantation is actively evolving in quality and scope to meet the challenges of a growing population of lung allograft recipients. In 2013, research groups leveraged large publicly available datasets in addition to multicenter research networks and single-center studies to make significant contributions to our knowledge and clinical care in the areas of donor use, clinical transplant outcomes, mechanisms of rejection, infectious complications, and chronic allograft dysfunction.

Longevity of patients with cystic fibrosis in 2000 to 2010 and beyond: survival analysis of the Cystic Fibrosis Foundation patient registry

BACKGROUND

Advances in treatments for cystic fibrosis (CF) continue to extend survival. An updated estimate of survival is needed for better prognostication and to anticipate evolving adult care needs.

OBJECTIVE

To characterize trends in CF survival between 2000 and 2010 and to project survival for children born and diagnosed with the disease in 2010.

DESIGN

Registry-based study.

SETTING

110 Cystic Fibrosis Foundation-accredited care centers in the United States.

PATIENTS

All patients represented in the Cystic Fibrosis Foundation Patient Registry (CFFPR) between 2000 and 2010.

MEASUREMENTS

Survival was modeled with respect to age, age at diagnosis, gender, race or ethnicity, F508del mutation status, and symptoms at diagnosis.

RESULTS

Between 2000 and 2010, the number of patients in the CFFPR increased from 21,000 to 26,000, median age increased from 14.3 to 16.7 years, and adjusted mortality decreased by 1.8% per year (95% CI, 0.5% to 2.7%). Males had a 19% (CI, 13% to 24%) lower adjusted risk for death than females. Median survival of children born and diagnosed with CF in 2010 is projected to be 37 years (CI, 35 to 39 years) for females and 40 years (CI, 39 to 42 years) for males if mortality remains at 2010 levels and more than 50 years if mortality continues to decrease at the rate observed between 2000 and 2010.

LIMITATIONS

The CFFPR does not include all patients with CF in the United States, and loss to follow-up and missing data were observed. Additional analyses to address these limitations suggest that the survival projections are conservative.

CONCLUSION

Children born and diagnosed with CF in the United States in 2010 are expected to live longer than those born earlier. This has important implications for prognostic discussions and suggests that the health care system should anticipate greater numbers of adults with CF.

PRIMARY FUNDING SOURCE

Cystic Fibrosis Foundation.

A consensus document for the selection of lung transplant candidates: 2014--an update from the Pulmonary Transplantation Council of the International Society for Heart and Lung Transplantation

The appropriate selection of lung transplant recipients is an important determinant of outcomes. This consensus document is an update of the recipient selection guidelines published in 2006. The Pulmonary Council of the International Society for Heart and Lung Transplantation (ISHLT) organized a Writing Committee of international experts to provide consensus opinion regarding the appropriate timing of referral and listing of candidates for lung transplantation. A comprehensive search of the medical literature was conducted with the assistance of a medical librarian. Writing Committee members were assigned specific topics to research and discuss. The Chairs of the Writing Committee were responsible for evaluating the completeness of the literature search, providing editorial support for the manuscript, and organizing group discussions regarding its content. The consensus document makes specific recommendations regarding the timing of referral and of listing for lung transplantation. These recommendations include discussions not present in previous ISHLT guidelines, including lung allocation scores, bridging to transplant with mechanical circulatory and ventilator support, and expanded indications for lung transplantation. In the absence of high-grade evidence to support decision making, these consensus guidelines remain part of a continuum of expert opinion based on available studies and personal experience. Some positions are immutable. Although transplant is rightly a treatment of last resort for end-stage lung disease, early referral allows proper evaluation and thorough patient education. Subsequent waiting list activation implies a tacit agreement that transplant offers a significant individual survival advantage. It is both the challenge and the responsibility of the transplant community globally to ensure organ allocation maximizes the potential benefits of a scarce resource, thereby achieving that advantage.

Lung transplantation in patients with cystic fibrosis: special focus to infection and comorbidities

Despite advances in medical care, patients with cystic fibrosis still face limited life expectancy. The most common cause of death remains respiratory failure. End-stage cystic fibrosis can be treated with lung transplantation and is the third most common reason for which the procedure is performed. Outcomes for cystic fibrosis are better than most other lung diseases, but remain limited (5-year survival 60%). For patients with advanced disease lung transplantation appears to improve survival. Outcomes for patients with Burkholderia cepacia remain poor, although they are better for patients with certain genomovars. Controversy exists about Mycobacterium abscessus infection and appropriateness for transplant. More information is also becoming available for comorbidities, including diabetes and pulmonary hypertension among others. Extra-corporeal membrane oxygenation is used more frequently for end-stage disease as a bridge to lung transplantation and will likely be used more in the future.

Assessing the causal effect of organ transplantation on the distribution of residual lifetime

Because the number of patients waiting for organ transplants exceeds the number of organs available, a better understanding of how transplantation affects the distribution of residual lifetime is needed to improve organ allocation. However, there has been little work to assess the survival benefit of transplantation from a causal perspective. Previous methods developed to estimate the causal effects of treatment in the presence of time-varying confounders have assumed that treatment assignment was independent across patients, which is not true for organ transplantation. We develop a version of G-estimation that accounts for the fact that treatment assignment is not independent across individuals to estimate the parameters of a structural nested failure time model. We derive the asymptotic properties of our estimator and confirm through simulation studies that our method leads to valid inference of the effect of transplantation on the distribution of residual lifetime. We demonstrate our method on the survival benefit of lung transplantation using data from the United Network for Organ Sharing.

Rationale and design of a randomized trial of home electronic symptom and lung function monitoring to detect cystic fibrosis pulmonary exacerbations: the early intervention in cystic fibrosis exacerbation (eICE) trial

BACKGROUND

Acute pulmonary exacerbations are central events in the lives of individuals with cystic fibrosis (CF). Pulmonary exacerbations lead to impaired lung function, worse quality of life, and shorter survival. We hypothesized that aggressive early treatment of acute pulmonary exacerbation may improve clinical outcomes.

PURPOSE

Describe the rationale of an ongoing trial designed to determine the efficacy of home monitoring of both lung function measurements and symptoms for early detection and subsequent early treatment of acute CF pulmonary exacerbations.

STUDY DESIGN

A randomized, non-blinded, multi-center trial in 320 individuals with CF aged 14 years and older. The study compares usual care to a twice a week assessment of home spirometry and CF respiratory symptoms using an electronic device with data transmission to the research personnel to identify and trigger early treatment of CF pulmonary exacerbation. Participants will be enrolled in the study for 12 months. The primary endpoint is change in FEV1 (L) from baseline to 12 months determined by a linear mixed effects model incorporating all quarterly FEV1 measurements. Secondary endpoints include time to first acute protocol-defined pulmonary exacerbation, number of acute pulmonary exacerbations, number of hospitalization days for acute pulmonary exacerbation, time from the end of acute pulmonary exacerbation to onset of subsequent pulmonary exacerbation, change in health related quality of life, change in treatment burden, change in CF respiratory symptoms, and adherence to the study protocol.

CONCLUSIONS

This study is a first step in establishing alternative approaches to the care of CF pulmonary exacerbations. We hypothesize that early treatment of pulmonary exacerbations has the potential to slow lung function decline, reduce respiratory symptoms and improve the quality of life for individuals with CF.

Survival benefit of lung transplant for cystic fibrosis since lung allocation score implementation

RATIONALE

The survival benefit of lung transplantation (LT) in adult patients with cystic fibrosis (CF) is debated.

OBJECTIVES

We sought to assess the survival benefit of LT in adult patients with CF.

METHODS

We used data from the United Network for Organ Sharing Registry to identify adult patients with CF on a wait list for LT in the United States between 2005 and 2009. Survival times while on the wait list and after LT were modeled by use of a Cox model that incorporated transplantation status as a time-dependent covariate. Evolution in lung allocation score (LAS) while on the wait list was used as a surrogate for disease severity. We fitted a model for the joint distribution of survival and longitudinal disease process (LAS over time).

MEASUREMENTS AND MAIN RESULTS

A total of 704 adult patients with CF were registered on a wait list during the study period. The cumulative incidence of LT was 39.3% (95% confidence interval, 35.6-42.9%) at 3 months and 64.7% (61.0-68.4%) at 12 months, whereas the incidence of death while on the wait list at the same times was 8.5% (6.4-10.6%) and 12.9% (10.3-15.5%), respectively. Survival after LT was 96.5% (94.7-98.2%) at 3 months; 88.4% (85.1-91.8%) at 12 months; and 67.8% (59.9-76.8%) at 3 years. LT conferred a 69% reduction in the instantaneous risk of death (51-80%). The interaction between LAS and LT was significant: the higher the LAS, the greater the survival benefit of LT (P < 0.001).

CONCLUSIONS

LT confers a survival benefit for adult patients with CF.

Pretransplant six-minute walk test predicts peri- and post-operative outcomes after pediatric lung transplantation

The purpose of the pretransplant assessment in lung transplantation is to determine a patient's need for transplant as well as their potential survival post-procedure. In 2005, the UNOS introduced the LAS, a calculation based on multiple physiologic measures to determine need and likelihood for survival. Measures include NYHA class and the 6-MWT. Some adult studies indicate a positive correlation with 6-MWT and waiting list survival. In pediatric/adolescent patients, there are minimal data regarding the predictive value of physiologic markers in either wait list survival or post-transplant outcome. A retrospective cohort study of 60 consecutive lung transplantations from 1990 to 2008 was performed at a pediatric tertiary care facility. Functional pretransplant assessments were abstracted from the medical record and compared with outcomes after transplantation.

RESULTS

a 6-MWT of >1000 ft (305 m) prior to transplantation correlated with a shorter ICU stay (7 vs. 11 days, p = 0.046) and fewer days of mechanical ventilation (2 vs. 4, p = 0.04). A pretransplant 6-MWT greater than 750 ft (229 m) correlated with shorter overall hospitalization (37 vs. 20 days, p = 0.03). Measuring pretransplant 6-MWT tests for pediatric patients is valuable in predicting peri-operative outcomes after lung transplantation.

Disparities in access to lung transplantation for patients with cystic fibrosis by socioeconomic status

RATIONALE

Although previous studies suggest that access to care for patients with cystic fibrosis (CF) does not vary appreciably by socioeconomic status (SES), disparities with respect to access to lung transplantation for patients with CF are largely unknown.

OBJECTIVES

To determine whether access to lung transplantation for patients with CF differs according to SES.

METHODS

Observational study involving 2,167 adult patients with CF from the CF Foundation Patient registry who underwent their first lung transplant evaluation between 2001 and 2009. The primary outcome was acceptance for lung transplant after initial evaluation. The main SES indicator was Medicaid status. Alternate SES indicators included race, educational attainment, ZIP code-level median household income, and driving time from residence to closest lung transplant center.

MEASUREMENTS AND MAIN RESULTS

The odds that Medicaid recipients were not accepted for lung transplant were 1.56-fold higher (95% confidence interval [CI], 1.27-1.92) than patients without Medicaid, after multivariate adjustment for demographic characteristics, disease severity, and potential contraindications to lung transplant, and before or after use of the lung allocation score. This association was independent of other SES indicators, including race, educational attainment, ZIP code-level median household income, and driving time to closest transplant center (odds ratio [OR] = 1.37; 95% CI, 1.10-1.72). Patients not completing high school (OR = 2.37; 95% CI, 1.49-3.79) and those residing in the lowest (vs. highest) ZIP code median household income category (OR = 1.39; 95% CI, 1.01-1.93) also experienced a higher odds of not being accepted for lung transplant in multivariate analysis.

CONCLUSIONS

In this nationally representative study of adult patients with CF, multiple indicators of low SES were associated with higher odds of not being accepted for lung transplant.

Sputum biomarkers and the prediction of clinical outcomes in patients with cystic fibrosis

Lung function, acute pulmonary exacerbations (APE), and weight are the best clinical predictors of survival in cystic fibrosis (CF); however, underlying mechanisms are incompletely understood. Biomarkers of current disease state predictive of future outcomes might identify mechanisms and provide treatment targets, trial endpoints and objective clinical monitoring tools. Such CF-specific biomarkers have previously been elusive. Using observational and validation cohorts comprising 97 non-transplanted consecutively-recruited adult CF patients at the Intermountain Adult CF Center, University of Utah, we identified biomarkers informative of current disease and predictive of future clinical outcomes. Patients represented the majority of sputum producers. They were recruited March 2004-April 2007 and followed through May 2011. Sputum biomarker concentrations were measured and clinical outcomes meticulously recorded for a median 5.9 (interquartile range 5.0 to 6.6) years to study associations between biomarkers and future APE and time-to-lung transplantation or death. After multivariate modeling, only high mobility group box-1 protein (HMGB-1, mean = 5.84 [log ng/ml], standard deviation [SD] = 1.75) predicted time-to-first APE (hazard ratio [HR] per log-unit HMGB-1 = 1.56, p-value = 0.005), number of future APE within 5 years (0.338 APE per log-unit HMGB-1, p<0.001 by quasi-Poisson regression) and time-to-lung transplantation or death (HR = 1.59, p = 0.02). At APE onset, sputum granulocyte macrophage colony stimulating factor (GM-CSF, mean 4.8 [log pg/ml], SD = 1.26) was significantly associated with APE-associated declines in lung function (−10.8 FEV₁% points per log-unit GM-CSF, p<0.001 by linear regression). Evaluation of validation cohorts produced similar results that passed tests of mutual consistency. In CF sputum, high HMGB-1 predicts incidence and recurrence of APE and survival, plausibly because it mediates long-term airway inflammation. High APE-associated GM-CSF identifies patients with large acute declines in FEV₁%, possibly providing a laboratory-based objective decision-support tool for determination of an APE diagnosis. These biomarkers are potential CF reporting tools and treatment targets for slowing long-term progression and reducing short-term severity.

Health-related quality of life in cystic fibrosis

PURPOSE OF REVIEW

To review the contribution of various therapeutic interventions on both longevity and quality of life in cystic fibrosis patients.

RECENT FINDINGS

Long-term survival in cystic fibrosis has increased markedly in the past 25 years, largely due to a robust clinical trials program carried out at Cystic Fibrosis Foundation accredited clinical centers in the United States and similar organizations worldwide. Cystic fibrosis patients are recommended complex, time-intensive daily therapies that are often difficult for families and patients to sustain long-term. Recently, attention to the perceived value of a particular therapy on a patient's well being is recognized as important for individualizing therapeutic regimens that provide maximal clinical benefit and are more likely to be adhered to long-term by the patient. Cystic fibrosis care is in a new era in which patient-related outcomes (PROs) for the assessment of health-related quality of life (HRQOL) are regarded with equal importance to medically beneficial therapies.

SUMMARY

Numerous advances in the clinical care of cystic fibrosis have led to improved survival, although definitive correction of the abnormal cystic fibrosis transmembrane regulator protein function remains elusive. Patients struggle to maintain rigorous, time-intensive therapeutic regimens, whereas clinicians strive to identify which interventions preserve quality of life. Cystic fibrosis patients depend on their caregiver's ability to assess both the medical benefit and the contribution to quality of life that therapeutic regimes bring to their disease. Caregivers, in turn, need measures of HRQOL in order to prioritize the various therapeutic interventions that are at their disposal in order to provide not just longevity, but meaningful quality of life.

Impaired immune function in children with Fanconi anaemia

Fanconi anaemia is an autosomal recessive or X-linked disease characterized by progressive bone marrow failure, variable congenital abnormalities and a predisposition to malignancy. Reports of immune function in this population are limited, and include only specific areas of immune performance, showing variable defects. We report a cross-sectional immunological assessment in 10 children with FA. Absolute numbers of B cells and natural killer (NK) cells were reduced compared to controls (P = 0·048 and P = 0·0002, respectively), while absolute number of T cells were within normal range. Perforin and granzyme content of NK cells was reduced (P < 0·00001 and P = 0·0057, respectively) along with the NK cell cytotoxicity (P < 0·001). Antigen proliferation in response to tetanus was decreased (P = 0·008) while responses to candida and phytohaemagglutinin were not. Cytotoxic T cell function was also reduced (P < 0·0001). Immunoglobulin G levels were normal in those evaluated. Our series represents the first attempt at a comprehensive quantitative and functional evaluation of immune function in this rare group of patients and demonstrates a significant deficit in the NK cell compartment, a novel quantitative B cell defect, along with abnormal cytotoxic function. These findings may be especially relevant in this patient population with known predisposition to DNA damage and malignancy.

Assessing survival benefits from lung transplantation

INTRODUCTION

Published studies used several methods to assess the impact of lung transplantation on patient survival. To interpret the results of these studies, a basic understanding of the models used and underlying hypotheses is required.

CURRENT KNOWLEDGE

The most often used method consists in assessing the survival of waiting-list patients and measuring the impact of lung transplantation on the baseline hazard (instantaneous risk) for death, usually with a Cox proportional hazards model. This strategy involves strong assumptions about the link between the baseline hazard in waiting-list patients and lung transplant recipients. Whether these assumptions are true is extremely difficult to establish. Some studies compared predicted survival without transplantation to observed survival after transplantation. We recently reported a new method in which predicted survival without transplantation is compared to predicted survival after transplantation.

PERSPECTIVES

All the methods described to date evaluate only the impact of transplantation on patient survival. The concomitant use of other markers such as respiratory function or quality of life would produce a more detailed picture of lung transplantation benefits.

CONCLUSION

Evaluating the benefits of lung transplantation involves the use of complex statistical methods. The results should be considered with circumspection, and none of the methods described to date allows definitive conclusions.

Guidelines for the selection of lung transplantation candidates

The present guidelines have been prepared with the consensus of at least one representative of each of the hospitals with lung transplantation programs in Spain. In addition, prior to their publication, these guidelines have been reviewed by a group of prominent reviewers who are recognized for their professional experience in the field of lung transplantation. Within the following pages, the reader will find the selection criteria for lung transplantation candidates, when and how to remit a patient to a transplantation center and, lastly, when to add the patient to the waiting list. A level of evidence has been identified for the most relevant questions. Our intention is for this document to be a practical guide for pulmonologists who do not directly participate in lung transplantations but who should consider this treatment for their patients. Finally, these guidelines also propose an information form in order to compile in an organized manner the patient data of the potential candidate for lung transplantation, which are relevant in order to be able to make the best decisions possible.