The impact of knee and hip chondrocalcinosis on disability in older people: the ProVA Study from northeastern Italy.

OBJECTIVES: Chondrocalcinosis is frequently associated with osteoarthritis. The role of osteoarthritis in the onset and progression of disability is well known. The impact of chondrocalcinosis on disability has never been investigated in epidemiological studies.
METHODS: Progetto Veneto Anziani is a survey of 3099 older Italians, focusing on chronic diseases and disability. Assessment was by questionnaires, physical performance tests and clinical evaluations. Chondrocalcinosis was determined by x-ray readings of 1629 consecutive subjects. Knee and hip osteoarthritis severity was evaluated by summing the radiographic features score (RFS) assigned during x-ray reading.
SUBJECTS: with chondrocalcinosis were older and more frequently women (age-adjusted p<0.0001). The gender association disappeared following adjustment for osteoarthritis severity. However, at the knee, the prevalence of osteoarthritis was higher in chondrocalcinosis patients independently of age and sex (age-adjusted p<0.0001). No difference was found between chondrocalcinosis and controls in sociodemographic variables and comorbidity. Knee chondrocalcinosis was strongly associated with clinical features of knee osteoarthritis and with disability assessment parameters in the bivariate analysis. Most associations remained after adjusting for age. After further adjustment for RFS, a significant association remained for knee deformity and pain, the need for a cane, difficulty walking 500 m, using a toilet, shopping and repeatedly rising from a chair.
CONCLUSIONS: Pain and physical function are the outcome measures of choice for assessing disability in osteoarthritis patients. The presence of chondrocalcinosis contributes to both, independently of age and osteoarthritis severity, thus compromising the quality of life and worsening comorbidity.