The prevalence, incidence, and progression of radiographic thumb base osteoarthritis in a population-based cohort:the Rotterdam Study

Objective: To describe the prevalence, incidence, and progression of radiographic thumb carpometacarpal (CMC-1) and trapezioscaphoid (TS) radiographic osteoarthritis (ROA) in the general Dutch population aged ≥55y. Design: Data were from the first and second cohort of the Rotterdam Study (1990–2005, 4–12 years follow-up, age 55+). Participants underwent bilateral radiographs at baseline (N = 7792) and follow-up (N = 3804), read for Kellgren–Lawrence (K-L) grade. ROA was defined on the joint level as K-L grade ≥2. The prevalence was assessed at baseline, incidence at follow-up in those free of ROA at baseline, and progression in those with ROA. Differences based on sex and age were evaluated using logistic regression models. Results: At baseline, 1977 (25.3%) had CMC-1 ROA and 1133 (14.5%) TS ROA. The prevalence was higher in females for CMC-1 (aOR = 1.98 95%CI [1.77–2.21]) and TS ROA (aOR = 2.00 [1.74–2.29]) and increased for every year of age (CMC-1 ROA 1.08 [1.07–1.08]) (TS ROA 1.06 [1.05–1.07]). Most (437/512; 85.4%) incident cases of CMC-1 ROA (2994 at risk) were mild (K-L = 2), whereas most (145/167; 86,8%) incident cases of TS ROA (3311 at risk) were moderate to severe (K-L = 3/4). CMC-1 ROA progression was mostly (88/100; 88.0%) seen in the K-L 2 group at baseline, whereas that was (4/17; 23.5%) for TS ROA. Conclusion: CMC-1 ROA and TS ROA are prevalent in the general Dutch population. While incident CMC-1 ROA was primarily mild, incident TS ROA was more often moderate to severe. CMC-1 ROA was a strong predictor for incident TS ROA.