Methods
Literature Search
A protocol detailing the methodology of this systematic review was developed. The methods used to perform this review involved both electronic and manual components, and followed established best methods used in the science of systematic review research. A literature search was performed in MEDLINE and EMBASE to identify all English-language observational studies, published from 1990 to March 2013, reporting on lung transplantation in patients with an underlying diagnosis of IPF. Additional file 1 http://www.biomedcentral.com/1471-2466/14/139/additional details the specific search strategy used. The electronic searches were supplemented by a manual search of the reference lists of all accepted studies, as well as the reference lists of recent relevant reviews. Data reported on the Organ Procurement and Transplantation Network (OPTN) and the International Society for Heart and Lung Transplantation (ISHLT) websites were also used in this review.
Study Identification
In the initial screening, abstracts were reviewed for obvious exclusion criteria, which included, guidelines, animal and in vitro studies, case reports, meta-analyses, clinical trials, and studies with no IPF patients or no lung transplantation. The full-text publications of accepted abstracts were reviewed to satisfy all of the pre-specified inclusion criteria. Eligible studies were those of observational design reporting on at least 10 patients with IPF who underwent lung transplantation, and reporting survival outcomes in IPF patients after lung transplantation or while on the waiting list for transplantation. Studies that only reported outcomes for a population with mixed diagnoses, such as all pulmonary fibrosis patients, without reporting IPF data separately were excluded. The most recent published reports from the ISHLT (2012 report) and the OPTN (2011 report) were included. The agreement of two investigators was required to accept or reject any articles during the review process.
Data Extraction and Synthesis
Data elements of interest from each accepted study were extracted to a data extraction form. Extracted information included study-level characteristics, patient-level characteristics, and outcomes of interest. One investigator extracted the data from each study, and a second investigator independently reviewed the extracted data for completeness and accuracy.