Independent review of the full texts identified three eligible cohort studies which were retrospective in design.
After the removal of duplicates, we identified 1937 articles, reviewed 33 in full text, and identified 21 articles of 16 cohorts as being eligible for this meta-analysis (see supplementary figure S1).
Original and review journal articles with available free abstract and full text were identified from the databases.
Full text articles identified by the search that will potentially meet inclusion criteria based on the title and abstract will be obtained for data synthesis.
7 8 10 Two investigators (FEK, PDM) independently screened the titles, abstracts, and full text of identified papers to determine their eligibility for inclusion (see supplementary file).
A full text screen identified only four studies (reported in 15 papers) that used longitudinal data methods over 12 months or more.
Finally, our inability to electronically retrieve 37 full text items, identified on the basis of our abstract search, means that we were unable to review some potentially relevant items.
One reviewer (HIM) screened titles and abstracts, reviewed the full text of identified studies and made initial decisions on eligibility according to prespecified inclusion criteria (see online supplementary table S4).
The conventional definition for hyponatraemia of serum sodium concentration ≤135 m m was used 11, 12. Two authors (JB and MG) independently reviewed the titles, abstracts and full text of identified papers.
To search for potential additional studies the electronic database search was supplemented by a manual check of references of recent reviews and primary full text articles identified with the search strategy, as described above.
