Feasibility of the FINDRISC questionnaire to identify individuals with impaired glucose tolerance in Swedish primary care. A cross-sectional population-based study.

AIM: To evaluate the performance of the FINDRISC questionnaire as a tool to recruit individuals with impaired glucose tolerance for lifestyle intervention programmes. METHODS: A cross-sectional population-based study in primary Health Care Centres in a middle-sized Swedish town. All 9734 individuals, aged 35-75 years, living within a defined area, were invited by mail to fill in and return the FINDRISC questionnaire. Participants with a risk score ≥ 15 (n = 525) were invited to perform an oral glucose tolerance test while those with known diabetes were excluded. RESULTS: In total, 5452 questionnaires (58%) were returned and revealed a mean risk-score of 8.5 ± 4.5 (mean ± SD). We found that 525 participants had a risk-score ≥ 15 and 302 (58%) were further examined with an oral glucose tolerance testing (OGTT). Among them we detected 11% with previously undiagnosed Type 2 diabetes, 16% with impaired glucose tolerance and 29% with impaired fasting glucose. A FINDRISC score ≥ 15 was associated with a positive predictive value of 55% for impaired glucose metabolism (impaired fasting glucose + impaired glucose tolerance + Type 2 diabetes) and of 16% for impaired glucose tolerance, respectively. The positive predictive value for impaired glucose tolerance did not increase to more than 17% when choosing the cut-point 17, while there was a significant increase in the positive predictive value for impaired glucose metabolism (70%). CONCLUSIONS: The FINDRISC questionnaire is a useful instrument for identification of individuals with impaired glucose metabolism but seems less effective for detection of individuals with impaired glucose tolerance. Strategies to find individuals with impaired glucose tolerance for implementation of lifestyle changes in primary care should therefore be developed further.