Objectives To describe the development of acronym use across five major medical specialties and to evaluate the technical and aesthetic quality of the acronyms.

Design Acronyms obtained through a literature search of Pubmed.gov followed by a standardised assessment of acronym quality (BEAUTY and CHEATING criteria).

Participants Randomised controlled trials within psychiatry, rheumatology, pulmonary medicine, endocrinology, and cardiology published between 2000 and 2012.

Main outcome measures Prevalence proportion of acronyms and composite quality score for acronyms over time.

Results 14 965 publications were identified, of which 18.3% (n=2737) contained an acronym in the title. Acronym use was more common among cardiological studies than among the other four medical specialties (40% v 8-15% in 2012, P<0.001). Except for within cardiology, the prevalence of acronyms increased over time, with the average prevalence proportion among the remaining four specialties increasing from 4.0% to 12.4% from 2000 to 2012 (P<0.001). The median combined acronym quality score decreased significantly over the study period (P<0.001), from a median 9.25 in 2000 to 5.50 in 2012.

Conclusion From 2000 to 2012 the prevalence of acronyms in trial reports increased, coinciding with a substantial decrease in the technical and aesthetic quality of the acronyms. Strict enforcement of current guidelines on acronym construction by journal editors is necessary to ensure the proper use of acronyms in the future.