Early detection of frail older people is important. Timely intervention may allow health care professionals to prevent or delay the occurrence of adverse outcomes such as disability, increases in health care utilization, and premature death.

We assessed the construct and criterion validity of the SUNFRAIL tool, a questionnaire for measuring frailty among older people.

This cross-sectional study was carried out in a sample of Dutch citizens. A total of 195 community-dwelling persons aged 71 years and older completed the questionnaire.

Construct validity was examined by determining the correlation between the SUNFRAIL tool and the Tilburg Frailty Indicator (TFI). Criterion validity for the SUNFRAIL tool was determined by establishing the correlations with chronic diseases and adverse outcomes of frailty (disability, falls, indicators of health care utilization). Disability was measured using the Groningen Activity Restriction Scale. Participants also answered questions regarding falls and health care utilization.

The construct validity of this tool was good and showed significant correlations with the TFI. The correlation between SUNFRAIL total and TFI total was 0.624. The criterion validity of the SUNFRAIL tool was good for chronic diseases and good-to-excellent for adverse outcomes disability, receiving nursing care, and falls. The area under the curve for these outcomes was 0.840 (95% CI 0.781–0.899), 0.782 (95% CI 0.696–0.868), and 0.769 (95% CI 0.686–0.859), respectively.

The results of our study suggest that the SUNFRAIL tool is a valid instrument for assessing frailty in community-dwelling older people. It is an attractive instrument for use in practice because it takes little time for health care professionals and older people to complete the questionnaire, and it expresses the integral functioning of human beings.