To describe the associations between hand osteoarthritis (OA), pain and disability in males and females and to further validate the Australian/Canadian OA hand index (AUSCAN LK3.0).
Cross-sectional study of 522 subjects from 101 Tasmanian families (males N=174, females N=348). Hand OA was assessed by two observers using the Altman atlas for joint space narrowing and osteophytes at distal interphalangeal and first carpometacarpal joints as well as a score for Heberden's nodes based on hand photography. Hand pain and function were assessed by the AUSCAN LK3.0 and grip strength by dynamometry in both hands on two occasions.
The prevalence of hand OA was high in this sample at 44-71% (depending on site). Pain and dysfunction increased with age while grip strength decreased (all P< 0.001). All three measures were markedly worse in women, even after taking the severity of arthritis into account. Hand OA explained 5.7-10% of the variation in function, grip strength and pain scores, even after adjustment for age and sex. Further adjustment suggested that the osteoarthritic associations with function and grip strength were largely mediated by pain. Severity of disease was more strongly associated with these scores than presence or absence. Lastly, the AUSCAN LK3.0 showed a comparable association to grip strength with structural damage providing further evidence of index validity.
Hand OA at these two sites makes substantial contributions to hand function, strength and pain. The associations with function and strength measures appear mediated by pain. Gender differences in all three measures persist after adjustment for variation in age and OA severity indicating that factors apart from radiographic disease are responsible.