Correspondence on: 'Irritable bowel syndrome symptoms in axial spondyloarthritis more common than among healthy controls: is it an overlooked comorbidity?' by Wallman et al. Issue 1 (9th December 2019) - Proft, Fabian; Protopopov, Mikhail; Rios Rodriguez, Valeria; Torgutalp, Murat; Siegmund, Britta; Poddubnyy, Denis