Self-report as an indicator of incident disease.
OBJECTIVE
Epidemiological studies use self-reports from repeated surveys to ascertain incident disease. However, the accuracy of such measurements remains unknown, as validity studies have typically relied on data from prevalent, rather than incident, disease. This study examined the validity of self-reports in the detection of new-onset disease with measurements at baseline and follow-up conditions.


METHODS
We conducted a prospective cohort study of 34,616 Finnish public-sector employees. Data from self-reported, physician-diagnosed diseases from two surveys approximately 4 years apart were compared with corresponding records in comprehensive national health registers used as the validity criterion.


RESULTS
There was a considerable degree of misclassification for self-reports as a measure of incident disease. The specificity of self-reports was equally high for the prevalent and incident diseases (range, 93%-99%), but the sensitivity of self-reports was considerably lower for incident than for prevalent diseases: hypertension (55% vs. 86%), diabetes (62% vs. 96%), asthma (63% vs. 91%), coronary heart disease (62% vs. 78%), and rheumatoid arthritis (63% vs. 83%).


CONCLUSIONS
This study suggests that the sensitivity of self-reports is substantially worse for incident than for prevalent diseases. Results from studies on self-reported incident chronic conditions should be interpreted with caution.
Centre for Expertise in Work Organisations, Finnish Institute of Occupational Health, Helsinki. tuula.oksanen@ttl.fi <tuula.oksanen@ttl.fi>
Tuula
T
Oksanen
Mika
M
Kivimäki
Jaana
J
Pentti
Marianna
M
Virtanen
Timo
T
Klaukka
Jussi
J
Vahtera
D001172:Arthritis, Rheumatoid / Q000453:epidemiology; D001249:Asthma / Q000453:epidemiology; D003327:Coronary Disease / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D005387:Finland / Q000453:epidemiology; D006306:Health Surveys; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012650:Self Disclosure; D012680:Sensitivity and Specificity