The impact of socioeconomic status on the link between osteoarthritis and the onset of common comorbidities.

OBJECTIVES

The temporal relationship between osteoarthritis and comorbidity is unclear and may vary with socioeconomic status. The aims of this study were to identify if osteoarthritis was associated with onset of common comorbidities, and if the association was moderated by deprivation.

METHODS

Prospective cohort study combining questionnaire and medical record data (n=3910). Associations between osteoarthritis and onset of comorbidity at the three-year follow-up were examined using regression models. Interaction terms and stratified analysis were used to examine moderation.

RESULTS

Osteoarthritis was associated with onset of all comorbidities (p<0.05). After adjusting for confounders, osteoarthritis was associated with onset of widespread pain (adjusted odds ratio 2.49; 95% confidence interval 1.96-3.17) and insomnia (1.58;1.14-1.19). Interactions between osteoarthritis and change in income and onset cognitive impairment (p=0.047; onset was higher when income became inadequate), and between osteoarthritis and education and onset widespread pain (p=0.012; onset was higher in those with high levels of education) were significant.

CONCLUSIONS

Consulters for osteoarthritis were more likely to develop physical and psychological comorbidities than those without osteoarthritis. The moderation analyses indicated that mechanisms to comorbidity differ by socio-economic strata and a need for different approaches to prevent comorbidity for consulters with OA from different levels of deprivation.