['Age-related changes in articular cartilage are likely to play a role in the etiology of osteoarthritis (OA). One of the major age-related changes in cartilage is the accumulation of advanced glycation end products (AGEs). The present study evaluates whether pentosidine can predict radiographic progression and/or burden over 5 years follow-up in a cohort of early knee and/or hip OA.', 'The 5 years follow-up data of 300 patients from cohort hip & cohort knee (CHECK) were used. Radiographic progression and burden were assessed by X-rays of both knees and hips (Kellgren and Lawrence (K&L) and Altman scores). Baseline pentosidine levels (and urinary CTXII as a comparator) were measured by high-performance-liquid-chromatography (HPLC) and enzyme linked immunosorbent assay (ELISA). Univariable and multivariable associations including baseline radiographic damage, age, gender, body mass index (BMI) and kidney function were performed.', 'Both pentosidine and urinary C-terminal telopeptide of type II collagen (uCTXII) correlated with radiographic progression and burden. In general pentosidine did not have an added predictive value to uCTXII for progression nor burden of the disease. The best prediction was obtained for burden of radiographic damage (R(2) = 0.60-0.88), bus this was predominantly determined by baseline radiographic damage (without this parameter R(2) = 0.07-0.17). Interestingly, pentosidine significantly added to prediction of osteophyte formation, whereas uCTXII significantly added to prediction of JSN in multivariable analysis.'] Is skin pentosidine in very early hip/knee osteoarthritis ( CHECK ) a strong independent predictor of radiographic progression over 5 years follow-up?