A short functional survey is responsive to changes in functional status in vulnerable older people

Abstract

Objectives: To investigate whether an abbreviated five-item functional status survey consisting of five activities of daily living (ADLs) reflects changes measured over time in a full 12-item functional status survey.

Design: Longitudinal evaluation with mean follow-up of 11 months.

Setting: Two managed-care organizations in the United States.

Participants: Four hundred twenty community-dwelling older people at moderate to high risk of death and functional decline enrolled in the Assessing Care of Vulnerable Elders (ACOVE) observational study.

Measures: Number of ADL abilities according to the short (range 0-5) and full functional status surveys (range 0-12); change in function as defined according to a 1-point change in short score and 1- to 2-point change in full survey scores.

Results: Changes in short functional status survey scores were highly correlated to changes in long survey scores (correlation coefficient=0.88). On average, a 1-point change in the short survey score was associated with a 1.4-point change on the long survey score (P<.001). The short survey correctly classified 93% of those who declined according to the long survey, adjusting for chance agreement (kappa=0.82) and was responsive to decline in function (sensitivity 82-94%, specificity 94-97%, and area under the receiver operating curve 0.91-0.93 for 1- to 2-point decreases in full survey ADL counts).

Conclusion: The short functional status survey is an efficient way to detect changes in functional status in vulnerable older populations for clinical and research purposes.

Figure 1. Change in Short Function Survey Reflects Change in Full Function Survey over 11 months (n=276)

Change in count of five functional abilities (bathing, walking, shopping, light housework, and managing finances) obtained by a short survey of 276 vulnerable elders were highly correlated (r=.88) with change in count of twelve functional abilities (bathing, walking across a room, dressing, transferring, using the toilet, feeding, shopping, light housework, meal preparation, managing finances, using the telephone, and medication management) obtained by a long survey of the same elders. Positive change scores = improvement in function; negative change score = decline. Random jitter was added to the plot to separate overlapping data points.