Background A number of epidemiological studies have shown a possible association between diabetes and osteoarthritis (OA). However, curently there is a lack of data on whether diabetes independently predicts pain and function deterioration in OA.
Objectives To assess influence of diabetes on pain and function measures in patients with established knee OA and in subjects with increased risk of knee OA.
Methods For the current study we used longitudinal data obtained from the Osteoarthritis Initiative (OAI) public use data set, which is available at http://oai.epi-ucsf.org. The OAI cohort consists of progression subcohort (patients with symptomatic tibiofemoral knee OA, n= 1390), incidence subcohort (subjects with increased risk of OA, n = 3284) and reference control subcohort (n=122). In the current analysis we used the longitudinal data from the both progression and incidence subcohorts. The selected outcome variables were Western Ontario McMaster Osteoarthritis Index (WOMAC), Knee Osteoarthritis Outcome Scale (KOOS) and timed 20 meter walk. Weight was measured using a balance beam scale, height was measured with a Stadiometer. The information on previously diagnosed diabetes was collected from the self-reported Charlson Comorbidity Index. All outcomes were assessed at baseline and years 1,2,3,4, and 5 except 20 meter walking test which had been performed yearly up to four year follow up. Generalized estimating equations (GEE) were used to model the relationship between outcomes measured over time and diabetes at study entry. The model was adjusted for demographic characteristics, prior knee surgery, baseline outcome pain or function measures, Physical Activity Scale for the Elderly, and body mass index.
Results On baseline, 151 (10.9%) patients in progression subcohort and 210 (6.4%) patients in incidence subcohort reported diabetes. The results of GEE analysis (Table) shows that after adjusting for multiple covariates, diabetes significantly predicted the impairment of most of the outcome measures in both the incidence and progression subcohorts of OAI.
Conclusions Diabetes is an independent predictor of longitudinal pain and function worsening in patients with symptomatic knee OA as well as in subjects who are at higher risk of knee OA development.
Disclosure of Interest None Declared