Prevalence of symptomatic basilar thumb joint osteoarthritis in the general population

Background/Purpose: While the radiographic prevalence of basilar thumb osteoarthritis (OA) is well described, little is known about whether this translates to clinically symptomatic arthritis. The purpose of this study is to determine the prevalence of physician-diagnosed thumb carpometacarpal (CMC) arthritis.

Methods: Using healthcare register data from Skåne County, in southern Sweden (predominantly Caucasian population 1.3 million), we identified all adults aged 20 years or older who consulted a physician at least once and were given a diagnosis code for OA of the first CMC joint (ICD-10 code M18). Data were analyzed over the 13-year period between 1999 and 2011. Using cross-referencing with the Swedish population register to exclude subjects who were deceased or had relocated out of the county by end of year 2011, we obtained frequencies and point prevalence estimates by age and gender. The population was reduced with 20% to compensate for the loss of patients seen by the private care practitioners exclusively (ICD-10 codes partially forwarded to the register).

Results: The point prevalence of physician-diagnosed symptomatic OA of the basilar thumb joint in adults was estimated to 1.3% overall (2.0% in women and 0.57% in men). The prevalence peaked in women aged 65-74 with prevalence of 5.3%. The corresponding peak in men was in men aged 75-84 with a prevalence of 1.7%.

Conclusion: In a well-defined population, the clinically important prevalence of basilar thumb OA is substantially higher in women than men, with peak prevalence in women between 60-79 years of age. Thumb base OA can have a large impact on function and activities of daily living, and the high prevalence in elderly women and men is a health and economic concern in an aging population.