Measuring activity limitations in walking: development of a hierarchical scale for patients with lower-extremity disorders who live at home.

OBJECTIVE: To develop a hierarchical scale that measures activity limitations in walking in patients with lower-extremity disorders who live at home. DESIGN: Cross-sectional study. SETTING: Orthopedic workshops and outpatient clinics of secondary and tertiary care centers. PARTICIPANTS: Patients (N=981; mean age +/- standard deviation, 58.6+/-15.4 y; 46% men) living at home, with different lower-extremity disorders: stroke, poliomyelitis, osteoarthritis, amputation, complex regional pain syndrome type I, and diabetic and degenerative foot disorders. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: (1) Fit of the monotone homogeneity model, indicating whether items can be used for measuring patients; (2) fit of the double monotonicity model, indicating invariant (hierarchical) item ordering; (3) intratest reliability, indicating repeatability of the sum score; (4) robustness, addressing the clinimetric properties within subgroups of patients; and (5) differential item functioning, addressing the validity of comparisons between subgroups of patients. RESULTS: Thirty-five of 41 dichotomous items had (1) good fit of the monotone homogeneity model (coefficient H=.50), (2) good fit of the double monotonicity model (coefficient H(T)=.33), (3) good intratest reliability (coefficient rho=.95), (4) satisfactory robustness (within subgroups of patients defined by age, sex, and diagnosis), and (5) some differential item functioning (6 items in amputees compared with nonamputees). CONCLUSIONS: A hierarchical scale, with excellent scaling characteristics, was developed to measure activity limitations in walking in patients with lower-extremity disorders who live at home. The measurements should be interpreted cautiously when making comparisons between amputees and nonamputees.

Labour participation of the chronically ill. A profile sketch.

BACKGROUND: To improve our understanding of the problematic labour market position of people with a chronic disease, this paper describes the participation rates of several subgroups of the chronically ill in the Netherlands, as well as the aspects by which the working chronically ill differ from those who are fully work-disabled and from those who are not working for other reasons. METHODS: Data for this study are derived from the Panel of Patients with Chronic Diseases, a nationwide study in the Netherlands. The results discussed here relate to data collected in 1998 from a representative sample of 1266 people aged 15-64 with various chronic somatic diseases. The factors taken into account include medical diagnosis, disease duration, episodic occurrence and frequency of symptoms, pain, fatigue, functional disabilities with respect to motor control, somatic autonomy and cognitive autonomy, as well as the covariates gender, age and education. CONCLUSION: Labour market position is primarily related to health problems that can be considered common consequences of a chronic illness, while no independent effect of specific disease diagnosis was observed. In comparison with fully work-disabled people, those who are employed experience less pain and fatigue and encounter fewer problems in motor control and cognitive functioning (besides being younger and more highly educated). The main factor besides gender, age and education, distinguishing employed from non-employed involves problems with motor control.