Evaluation of the sensitivity and specificity of basal plasma adrenocorticotrophic hormone concentration for diagnosing pituitary pars intermedia dysfunction in horses: A systematic review.

This research systematically evaluated the effectiveness of ACTH as a diagnostic test for pituitary pars intermedia dysfunction (PPID) in horses. The study found that while the ACTH test showed high specificity, there were significant variations between studies, and many exhibited bias or inadequate design.

Research Methodology

• The researchers conducted a thorough analysis of past studies, examining the use of basal adrenocorticotrophic hormone (ACTH) to diagnose pituitary pars intermedia dysfunction (PPID) in horses.
• They three times scrutinized electronic databases, in January 2019, September 2020, and January 2021, to gather all English language publications pertaining to the diagnosis of PPID using the ACTH test, concentrating on studies published before these dates.
• Publications were screened, data were extracted, and the quality of the investigation was assessed by predefined criteria set by the authors. The study design, methodology, and reported information in the included studies were evaluated using the Standards for Reporting of Diagnostic Accuracy (STARD) checklists.
• The researchers also assessed the risk of bias and relevance using the Quality Assessment tool for Diagnostic Accuracy Studies (QUADAS-2) tool.

Study Findings

• Despite identifying 415 publications, only 25 could be evaluated in full, and out of those, 11 met the inclusion criteria.
• Most studies reported that basal ACTH demonstrated good sensitivity (with an overall median of 75.5% and a range of 36.0-100%) and excellent specificity (with an overall median of 95.2% and a range of 63.3-100%) for diagnosing PPID in horses.
• However, researchers identified notable variations between studies which prevented them from performing a meta-analysis. Additionally, issues in study design, the chosen study groups, and the possibility of bias were brought forward upon STARD and QUADAS-2 evaluations.
• The review concluded that the ACTH tests were more effective at ruling out PPID rather than diagnosing it.

Implications

• This study underscores the importance of well-constructed studies and methods in diagnostic test evaluations. The diversity in study designs, methodologies and potential biases highlighted the need for more standardization in these areas.
• It also emphasized the utility of ACTH in excluding PPID in horses, rather than confirming it, suggesting that alternate or additional methods may be required for accurate diagnosis.