Are self-reported medical conditions and medicine use from middle-aged and older adults credible? A validation study comparing Danish SHARE-data with National Health Register data.

Purpose: Self-reported information on medical conditions and medicine use is widely used in epidemiological research. We investigated the validity of self-reported medical conditions and medicine use from Danish participants in the Survey of Health, Ageing and Retirement in Europe.

Methods: Self-reported health data were linked at individual level with the National Patient Registry and the Danish National Prescription Registry (n = 5572).