A multicenter prospective study validated a nomogram to predict individual risk of dependence in ambulation after rehabilitation

Objectives: To develop the Functional Risk Index for Dependence in Ambulation (FRIDA) score, a nomogram to predict individual risk of dependence in ambulation at discharge from postacute rehabilitation and validate its performance temporally and spatially. Study design and setting: We analyzed the database of a multicenter prospective observational quality cohort study conducted from January 2012 to March 2016, including data from 8,796 consecutive inpatients who underwent rehabilitation after stroke, hip fracture, lower limb joint replacement, debility, and other neurologic, orthopedic, or miscellaneous conditions. Results: A total of 3,026 patients (34.4%) were discharged dependent in ambulation. In the training set of 5,162 patients (58.7%), Lasso-regression selected advanced age, premorbid disability, and eight indicators of medical and functional adverse syndromes at baseline to establish the FRIDA score. At the temporal validation obtained on an external set of 3,234 patients (41.3%), meta-analyses showed that the FRIDA score had good and homogeneous discrimination (summary area under the curve 0.841, 95% confidence interval = 0.826-0.855, I2 = 0.00%) combined with accurate calibration (summary Log O/E ratio 0.017, 95% confidence interval -0.155 to 0.190). These performances remained stable at spatial validation obtained on 3,626 patients, with substantial heterogeneity of estimates across nine facilities. Decision curve analyses showed that a FRIDA score-supported strategy far outperformed the usual "treat all" approach in each impairment categories. Conclusion: The FRIDA score is a new clinically useful tool to predict an individual risk for dependence in ambulation at rehabilitation discharge in many different disabilities, and may also reflect well the case-mix composition of the rehabilitation facilities.