Context: The reporting quality of randomized controlled trials (RCTs) is poor in general medicine and several areas of specialization, but unknown in endocrinology.

Objective: Our aim was to assess the reporting quality of RCTs in general endocrinology. A secondary objective was to identify predictors for better reporting quality.

Design and Setting: We systematically reviewed RCTs published in three general endocrinology journals between January 2005 and December 2006.

Participants: We included parallel design RCTs that addressed a question of treatment or prevention. Article selection and data abstraction were conducted by two reviewers independently and disagreements were resolved by consensus.

Main outcomes: There were two main outcomes: 1) a 15 -point overall reporting quality score (OQS) based on the Consolidated Standards for Reporting Trials (CONSORT); and 2) a 3- point key score, based on allocation concealment, blinding and use of intention-to-treat analysis.

Results: Eighty nine RCTs were included. The median OQS was 10 (interquartile range = 2). Allocation concealment, blinding, and analysis by intention to treat were reported in 10, 20 and 16 out of the 89 RCTs respectively. A multivariable regression analysis showed that complete industrial funding (incidence rate ratio (IRR) = 1.014(95% CI: 1.010 to 1.018), journal of publication (IRR=1.068 (95% CI: 1.007 to 1.132) and sample size (IRR= 1.048 (95% CI: 1.026 to 1.070) were significantly associated with a slightly better OQS.

Conclusions: The quality of RCT reporting in general endocrine literature is suboptimum. We discuss our results, highlight the areas where improvements are needed and provide some recommendations.