Detecting change in patient outcomes in a rural ambulatory rehabilitation service: the responsiveness of Goal Attainment Scaling and the Lawton Scale.

Abstract

The Wagga Wagga Ambulatory Rehabilitation Service (WWARS) clinicians felt the Australian Modified Lawton's Instrumental Activities of Daily Living Scale (Lawton Scale) was unresponsive to changes detected in many patients following their individualised programs. This study examined the performance of the Goal Attainment Scaling (GAS) concomitantly with the Lawton Scale in ambulatory rehabilitation patients. Consecutive patients (n = 83) of WWARS were evaluated pre and post treatment with the Lawton Scale and GAS. The statistical properties, particularly responsiveness, of the scales were compared. Statistically significant change (P < 0.001) was observed following treatment on both the Lawton Scale and GAS. Mean GAS scores changed by 38.7% compared with 8.3% for the Lawton Scale. GAS demonstrated a greater effect size (Cliff's δ) of 1.67 (95% confidence interval 1.51-1.91) than the Lawton Scale 0.83 (95% confidence interval 0.57-0.94). In 33.7% of patients, the Lawton Scale was invariant but improved with GAS. GAS was a more responsive measure than the Lawton Scale in rural ambulatory rehabilitation patients. Consequently, GAS is recommended as a performance outcome measure in the evaluation of ambulatory rehabilitation services to supplement standardised outcome measures such as the Lawton Scale.