Chondrocalcinosis and physical disability in the elderly. Results of the Pro.VA study

Purpose: Chondrocalcinosis (CC) is a rheumatological disorder characterized by calcification of the articular cartilage, mainly due to intra-articular calcium pyrophosphate dihydrate (CPPD) deposition, that has characteristic imaging appearances and could be easily visualized at X-ray reading. We have already reported that, in an Italian elderly population, the prevalence of CC was 10.4%, increased with age and it was more prevalent in women. Disability is a common finding in the elderly and its prevalence is higher in women and increases with age. It is known that osteoarthritis (OA) plays an important role in the onset and in the progression of disability. Besides the clinical assessment, disability can be evaluated by mean of specific questionnaires that include targeted questions and tests to measure the ability of performing activities that range from basic home-care to physical tasks. It has been demonstrated that such measures provide useful prognostic information about adverse outcomes. In the light of these considerations and of the association of CC with OA, we undertook a study aimed at evaluating the independent impact of CC on physical disability in an Italian elderly population. Methods: The population considered is that of the Progetto Veneto Anziani (Pro.V.A.) Study, a large observational community-based survey of elderly subjects residents in Northeastern Italy. The present study was conducted in a subpopulation of the Pro.V.A. cohort, consisting of 1629 subjects of both sexes (42% males, 58% females) aged 65 or older (mean 75.3+/-7.3, males 75.8+/-7.6, females 74.9+/-7.0). Results: Knee CC was associated with a higher radiological grade of OA, in particular at the right limb (5.7 vs 3.8 controls, age-adjusted p<0.0001). CC at the knee was also strongly associated with clinical features of OA. The association between CC and physical disability measures was significant at the bivariate analysis. CC was still significantly associated with most of the disability items after adjustment for age and, even after a further adjustment for OA radiological grade, a significant association remained for some features such as difficulty at walking 500 m. A linear trend of association was also shown for the summary performance score used for the evaluation of the lower extremity function. Conclusions: In conclusion, our study demonstrates that CC provides an independent contribution to physical disability, at least in the elderly.