Frequency, severity and determinants of functional limitations in older adults with joint pain and comorbidity: results of a cross-sectional study.

Older adults with joint pain and comorbidity are especially at risk of becoming functionally impaired. Therefore, we studied the frequency and severity of functional limitations and identified potential modifiable determinants that may reduce functional limitations. A prospective cohort study of older adults (≥65 years) with joint pain and comorbidity provided cross-sectional baseline data (n=407). Based on the International Classification of Functioning, Disability and Health (ICF) model, we measured Physical Functioning; PF, (Instrumental) Activities of Daily Living; (I)ADL, and participation. Apart from examining the frequency and severity, we identified determinants of functional limitations with multivariate regression analyses, by adding determinants in two steps: (1) only physical determinants, (2) physical and psychosocial determinants. Limitations in PF, ADL, IADL and participation were present in 66%, 31%, 61% and 47% of the participants, respectively. About 22% reported limitations on all four measures. Of the physical determinants, especially frailty and higher pain intensity were related to functional limitations. Remarkably, adding psychosocial determinants to the model weakened some of these relations. The psychosocial determinants were especially related to poor PF (i.e. anxiety symptoms, activity avoidance and poor general health perception) and participation restrictions (i.e. depressive symptoms, less social support). An inverse relation was present between self-efficacy and both outcomes. In conclusion, our sample reported substantial levels of functional limitations. More depressive symptoms, more activity avoidance and less social support were indicative of more functional limitations, whereas higher perceived self-efficacy was indicative of better functioning. Such psychosocial determinants should receive more attention in research.