Prognosis of functional deterioration in osteoarthritis

Functioning in patients with osteoarthritis of the hip or knee deteriorates less rapidly than expected. During a period of three years functioning remains relatively stable. Individual patients show considerable differences. In particular comorbidity is an important prognostic factor for functional deterioration. This was stated by Gabriella van Dijk in her thesis ‘Course of limitations in activities in elderly patients with osteoarthritis of the hip or knee’, which she defended October 26th at the VU University in Amsterdam.

Patients with knee or hip osteoarthritis often experience pain and limitations in activities, such as walking, climbing stairs and kneeling. Especially in elderly patients the disease frequently leads to disability. Little was known, however, about the course of functioning over time. Cross-sectional studies show that limitations in activities are associated with biomechanical, psychological and clinical factors. It was not known whether these factors also predict future functioning. Gabriella van Dijk tried to gain insight into the course of limitations in activities in elderly patients with osteoarthritis of the hip or knee and factors that predict it. She conducted a cohort study in which 237 patients with hip or knee osteoarthritis were followed during a period of three years. Patients were recruited from hospitals and rehabilitation centres and measurements were performed annually by tests and questionnaires.

Prognostic factors
“Three years is too short to detect functional deterioration. Limitations in activities remained relatively stable during a period of three years. But individual patients show considerable differences: some patients deteriorate, others don’t. Identification of prognostic factors is therefore highly relevant.” Van Dijk found that comorbidity, and increased pain, reduced range of motion and muscle strength after one year predicted worsening of limitations in activities after three years. Also relatively poor cognitive functioning plays a little role. In knee osteoarthritis, vitality also is an important factor. Low vitality, for example feeling tired and having no energy, predicts deterioration of functioning after three years.

With these results clinical practitioners can estimate the course of individual patients and select patients that are suspect to deterioration. Besides, results of this study underline that interventions need to be developed that account for osteoarthritis but also for all other diseases the patient suffers from.