FP338
QUALITY OF REPORTING OF CKD COHORT STUDIES BEFORE AND AFTER STROBE: A SYSTEMATIC REVIEW

Introduction and Aims: The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement was published in October 2007 to address quality of reporting of observational studies.To date only two of the 60 nephrology journals have endorsed this. The reviews aim was to assess the impact of the publication of the STROBE statement on reporting quality of observational study in nephrology literature.

Methods: Medline and Embase were searched for worldwide pre-dialysis CKD cohort studies,to look at reporting in two time periods:a.pre-STROBE:1/1/2002-31/12/2007 b.post-STROBE:1/1/2008-31/12/2013.The articles identified were double sifted at title, abstract and full text stage. Articles meeting pre-agreed criteria were scored by two reviewers independently based on STROBE cohort checklist(22 checklist items & sub-criteria captured in 55 questions). Two scores were calculated 1.STROBE question score(SQS):Number of articles adequately reporting a criterion divided by the number in which this criterion was applicable, expressed as a percentage 2.Manuscript STROBE score (MSC) defined as the number of the 55 questions adequately reported in the article divided by the number of applicable items,expressed as a percentage. Comparisons between pre and post SQS & MSC were performed by calculating odds ratios (OR) with 95% confidence intervals and Mann-Whitney(MW) test respectively. Longitudinal analysis of the MSC was carried out by dividing the articles into 4 periods(early pre, immediate pre & post and late post) with two-by-two comparisons using MW test with Bonferroni’s correction.Sub-group analysis was carried out restricting to nephrology and STROBE endorsing and non-endorsing journals.

Results: The identified 3621 articles were sifted down to 37 articles-11 Pre & 26 Post,19 European & 18 American and 22 nephrology & 15 other medical journals. Some STROBE criteria saw relevant improvements over the period such as objectives reporting(SQS 73%vs96%,OR 9.4 p= 0.07), choice of quantitative groups(SQS 30%vs75%, OR 5.7,p=0.04) and description of and carrying out sensitivity analysis(SQS 18%vs58%,OR 6.14,p=0.04 & 18%vs65%, OR 8.5,p=0.02, respectively.However the STROBE criteria relating to hypothesis stating,sample size estimation, addressing of missing data, and flow diagram continue to be under reported with less than 30% reporting in studies over the two periods. Pre- and post-period analysis revealed MSC increase(median score 77.8%(IQR:51.1-84.6) vs 83%(IQR:39.6-90),p=0.05). Restricting to nephrology journals the pre(N=6) and post-STROBE(N=22), MSC was 72.3 (IQR:64.7-84.6) and 83.4 (IQR:39.6-90.2) respectively (p=0.10).Analysis restricting to STROBE endorsing (76.5vs83,p=0.15) and non-endorsing journals (79.9vs83.7,p=0.10) showed no statistically significant change over the period. Longitudinal analysis,showed no significant trend in improvement over time.

Conclusions: This study highlights continuing deficiencies in the reporting of STROBE items and their sub-criteria. Given that only 2 renal journals have endorsed the STROBE statement,any evidence of improvement in reporting quality of cohort studies in nephrology literature is probably due to the penetration of STROBE statement over time rather than to its endorsement by journals.