Function and disability or quality of life? Issues illustrated by the Osteoporosis Functional Disability Questionnaire (OFDQ)

There continues to be a lack of consensus on the meaning and definition of the concept of quality of life. An implicit distinction for many measures of quality of life is from measures of health status based upon the presence of disability in functional domains. A further assumption in many scales is that quality of life is a unitary construct. The Osteoporosis Functional Disability Questionnaire (OFDQ) assessed some domains of function but is not unidimensional. It was developed to evaluate the progress and outcome of a structured exercise program for people with spinal compression fractures due to osteoporosis. The OFDQ assesses five domains relevant to the pain and disability in this population: pain, depression, function in performing common daily activities, socialization, and confidence in the exercise program. Longitudinal data from three cases are used to illustrate the utility of this multidimensional approach in evaluating the outcome of exercise treatment and understanding important aspects of the subjective life of people with osteoporosis.