Selection of patients with cystic fibrosis for lung transplantation

Long-term benefits in lung function and nutritional status of strict metabolic control of cystic fibrosis-related diabetes

Cystic fibrosis related diabetes (CFRD) is a strong determinant for lung function decline and increased mortality. Insulin treatment of CFRD is reportedly beneficial for this situation. We report on the long-term impact of insulin treatment of CFRD on pulmonary function and nutritional status in a CF male patient since diagnosis of diabetes. We report the case of a patient diagnosed with CF at the age of 16. Two years later, he experienced a rapidly evolving decrease in pulmonary function, some months later criteria were met warranting lung transplantation. Concomitantly, he was diagnosed with CFRD and insulin therapy was started. Lung function (spirometry), nutritional status (body mass index) and metabolic control (HbA(1c)) were determined every 3 months. After the introduction of insulin treatment, pulmonary function and nutritional status progressively improved and good glycemic control was achieved. The significant and sustained improvement in pulmonary function allowed for the patient's withdrawal from the lung transplantation program within 4 months, a situation which has been maintained until now, 8 years later. The long follow-up of our patient documents the rapid and prolonged beneficial effect of proper metabolic control of CFRD on the respiratory deterioration in CF.

Lung transplantation and survival in children with cystic fibrosis: solid statistics--flawed interpretation

In their provocative paper, "Lung transplantation and survival in children with cystic fibrosis," Liou and colleagues state that "Prolongation of life by means of lung transplantation should not be expected in children with cystic fibrosis. A prospective, randomized trial is needed to clarify whether and when patients derive a survival and quality of life benefit from lung transplantation." Unfortunately, that conclusion is not supportable. Liou's dataset introduced bias against transplantation by using covariates obtained well before the time of transplant (when predicted survival was good) and having a cohort with lower than expected post-transplant survival than reported elsewhere. The calculated hazard ratios are based on factors that may have changed between listing and transplant, and do not reflect true benefit on a patient by patient basis. The findings of the study are contrary to other studies using similar methods. Finally, recent changes in US lung transplant allocation policy may have made the study findings moot. In contrast to Liou's suggestion to perform an ethically and logistically challenging randomized trial to verify the benefit of lung transplantation, a research agenda is recommended for pediatric lung transplantation for cystic fibrosis that focuses on developing strategies to continually reassess and maximize quality of life and survival benefit.

Clinical scoring systems in cystic fibrosis

The first cystic fibrosis (CF) scoring system was published in 1958. Since then, many other scoring systems were developed. Clinical parameters, details about statistical evaluations, and recent strategic uses of scores were identified. Several similar scores aiming to assess chronic illness severity (Shwachman-Kulczycki score and a modification, Cooperman, Berneze-score and the NIH score) have not been evaluated and are out of date, given the changing natural history of CF. Of the current scoring systems, the modified Shwachman score by Doershuk is perhaps most reliable for describing follow-up studies. Scores designed for acute changes and short-term evaluation were also developed. The modified Huang score may be useful in the prognostic evaluation of patients with end-stage disease. It could also be used for discrimination of adult patients with differing disease severity and for longitudinal evaluation. Scores assessing pulmonary exacerbations could help provide consensus among clinicians regarding the need for intervention. Most of these scores require further evaluation. Although scores could provide an objective measure of disease severity, progression, need for and response to interventions, including value in selecting patients for lung transplantation and as an outcome measure for research studies, no scoring system can fulfill all these objectives. Nevertheless, there is a need for the development of a modern day longitudinal score that is sensitive, valid and reproducible, to reflect the milder disease status of patients.

Use of Lung Transplantation Survival Models to Refine Patient Selection in Cystic Fibrosis

Lung transplantation in cystic fibrosis may improve survival for patients with low 5-year predicted survival. Identifying characteristics that affect post-transplantation survival may improve patient selection and survival benefit. Using Cystic Fibrosis Foundation Patient Registry and United Network for Organ Sharing data, we identified 845 lung transplant recipients from 1991-2001, and 12,826 control patients from 1997. We used Cox proportional hazards models to identify variables that influence post-transplantation survival. To estimate the survival benefit of transplantation for patients affected by identified variables, we compared Kaplan-Meier survival curves of transplanted and control patients stratified by 5-year predicted survival. Post-transplantation survival improved annually. Youth, Burkholderia cepacia, and cystic fibrosis-related arthropathy increased the post-transplantation hazard of death. Compared with control subjects, transplanted adults with a 5-year predicted survival of less than 50% without B. cepacia or arthropathy have improved survival. Transplanted adults with B. cepacia, arthropathy, or a 5-year predicted survival of greater than 50% have decreased survival. Transplantation never improves survivorship for pediatric patients. Patients with arthropathy, B. cepacia infection, or younger age derive no aggregate survival benefit and must appraise carefully the high risk of decreased post-transplantation survival. Adult patients with low 5-year predicted survival without B. cepacia infection should receive priority for lung transplantation.

Bronchiectasis: sex and gender considerations

Bronchiectasis in women may act more virulently. Identified gender and sex differences range from increased exposure risks to altered inflammatory responses. Common among the most well-documented examples is a differential immune response. There is sufficient evidence to suggest that chronic airway infection, most notably non-CF bronchiectasis, is a more common and more virulent disease in women. This is particularly evident in CF-and non-HIV-related environmental mycobacterial respiratory tract infections. Whether this represents an inflammatory-immune process, or environmental, anatomic, or other genetic difference remains to be detailed fully.