Arthritis Prevalence Is Significantly Underestimated

The prevalence of arthritis has been substantially underestimated by current surveillance methods, especially among adults 65 years old and older, according to a recent study.

National estimates of arthritis prevalence currently rely on responses the question on doctor-diagnosed arthritis without using additional information on joint symptoms. These surveys have a sensitivity of 53% for participants age 45 to 64 years and 69% for participants 65 years of age and older, which results in the misclassification of almost half to one-third of respondents.
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To better assess the prevalence of arthritis, the researchers used data from the 2015 National Health Interview survey to develop a Bayesian multinomial latent class model. Their model included joint symptoms and symptom duration that exceeded 3 months in addition to doctor-diagnosed arthritis.

Of the 33,672 participants, 19.3% of men and 16.7% of women from 18 to 64 years of age reported joint symptoms without doctor-diagnosed arthritis. Additionally, 15.7% of men and 13.5% of women who were 65 years of age or older reported joint symptoms without doctor-diagnosed arthritis.

Among men, the measurement error-adjusted prevalence of arthritis was 29.9% for those from 18 to 64 years of age and 55.8% for those 65 years of age or older. The measurement error-adjusted prevalence of arthritis among women was 31.2% for those 18 to 64 years of age and 68.7% for those 65 years of age or older.

Overall, arthritis affected 91.2 million adults in the United States in 2015, which included 61.1 million individuals from 18 to 64 years of age. This prevalence estimate is 68% higher than previously reported national estimates for arthritis.

“Arthritis prevalence in the US population has been substantially underestimated, especially among adults [younger than] 65 years,” the researchers concluded. “Our findings are important because of underestimated, yet enormous, economic and public health impacts of arthritis including healthcare costs and costs from loss of productivity and disability, including in adults younger than 65 years of age.”

—Melissa Weiss

Reference:

Jafarzadeh SR, Felson DT. Updated estimates suggest a much higher prevalence of arthritis in US adults than previous ones [published online November 27, 2017]. Arthritis Rheumatol. doi:10.1002/art.40355.