Quality of Reporting of Observational Longitudinal Research

TLDR

Observational longitudinal research is valuable for etiology, prognosis, and clinical decision making, yet no structured reporting guidelines exist for this design. The authors created a checklist of internal and external validity criteria and a participant‑flow diagram to improve reporting of observational longitudinal studies. They defined checklist items covering recruitment, data collection, biases, analysis, and generalizability, and applied it via two independent raters to 49 stroke‑research articles from 1999‑2003 across six journals. Only 17 of 33 checklist items were reported on average, design items were better reported than internal‑validity items, and no link was found between study type or word count and reporting quality, leading the authors to recommend using the checklist and flow diagram.

Abstract

Observational longitudinal research is particularly useful for assessing etiology and prognosis and for providing evidence for clinical decision making. However, there are no structured reporting requirements for studies of this design to assist authors, editors, and readers. The authors developed and tested a checklist of criteria related to threats to the internal and external validity of observational longitudinal studies. The checklist criteria concerned recruitment, data collection, biases, and data analysis and descriptive issues relevant to study rationale, study population, and generalizability. Two raters independently assessed 49 randomly selected articles describing stroke research published from 1999 to 2003 in six journals: American Journal of Epidemiology, Journal of Epidemiology and Community Health, Stroke, Annals of Neurology, Archives of Physical Medicine and Rehabilitation, and American Journal of Physical Medicine and Rehabilitation. On average, 17 of the 33 checklist criteria were reported. Criteria describing the study design were better reported than those related to internal validity. No relation was found between study type (etiologic or prognostic) or word count and quality of reporting. A flow diagram for summarizing participant flow through a study was developed. Editors and authors should consider using a checklist and flow diagram when reporting on observational longitudinal research.