In clinical research information can be retrieved through various sources. The aim is to evaluate the agreement between answers in patient questionnaires and clinical reports in a study of patients after radical prostatectomy and patient characteristics associated with agreement between these two data sources.
In the prospective non-randomized longitudinal trial LAParoscopic Prostatectomy Robot Open (LAPPRO) 4003 patients undergoing radical prostatectomy at 14 centers in Sweden were followed. Analysis of agreement is made using a variety of methods, including the recently proposed Gwet's AC1, which enables us to handle the limitations of Cohen's Kappa where agreement depends on the underlying prevalence.
The incidence of postoperative events was consistently reported higher by the patient compared with the clinical reports for all outcomes. Agreement regarding the absence of events (negative agreement) was consistently higher than agreement regarding events (positive agreement) for all outcome variables. Overall impression of agreement depends on which measure used for the assessment. The previously reported desirable properties of Gwet's AC1 as well as the patient characteristics associated with agreement were confirmed.
The differences in incidence and agreement across the different variables and time points highlight the importance of carefully assessing which source of information to use in clinical research.
ISRCTN06393679 ( www.isrctn.com ). Date of registration: 07/02/2008. Retrospectively registered.
BMC urology. 2019 May 08*** epublish ***
David Bock, Eva Angenete, Anders Bjartell, Jonas Hugosson, Gunnar Steineck, Sofie Walming, Peter Wiklund, Eva Haglind
Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SSORG (Scandinavian Surgical Outcomes Research Group), Sahlgrenska University Hospital/Östra, 416 85, Gothenburg, Sweden. ., Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SSORG (Scandinavian Surgical Outcomes Research Group), Sahlgrenska University Hospital/Östra, 416 85, Gothenburg, Sweden., Department of Urology, Skåne University Hospital, Malmö, Sweden., Department of Urology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden., Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg, Sweden., Department of Molecular Medicine and Surgery, Section of Urology, Karolinska Institutet, Stockholm, Sweden.