Validity of self-report of fractures: Results from a prospective study in men and women across Europe

In population-based studies of osteoporosis, ascertainment of fractures is typically based on self-report, with subsequent verification by medical rec ords. The aim of this analysis was to assess the validity of self-report of incident nonspine fractures using a postal questionnaire. The degree of ov erreporting of fracture (false positives) was assessed by comparing self-re ports of new fracture from respondents in the multicenter European Prospect ive Osteoporosis Study with data from other sources including radiographs a nd medical records. In the analysis, 563 subjects reported nonspine fractur es. Verification of the presence of fracture was possible in 510 subjects. Of these, fractures were not confirmed in 11% (false positives). The percen tage of false positives was greater in men than in women (15% vs 9%, p=0.04 ), and less for fractures of the distal forearm and hip than for fractures at other sites. In a separate study, the degree of underreporting (false ne gatives) was assessed by follow-up of 251 individuals with confirmed fractu re ascertained from the records of fracture clinics in three European cente rs (Lubeck, Oviedo, Warsaw. Questionnaire responses were received from 174 (69%) subjects. Of these, 12 (7%) did not recall sustaining a fracture (fal se negatives). The percentage of false negatives was lower for hip and dist al forearm fractures with only 3 of 90 (3%) such fractures not recalled. Us ing the combined data from both studies, of those who reported a 'date' of fracture on the questionnaire, 91% of subjects were correct to within 1 mon th of the actual date of the fracture. A postal questionnaire is a relative ly simple and accurate method fur obtaining information about the occurrenc e of hip and distal forearm fractures, including their timing. Accuracy of ascertainment of fractures at other sites is less good and where possible s elf-reported fractures at such sites should be verified from other sources.