Arthritis prevalence in the US population has been substantially underestimated, especially among adults aged <65 years, according to a recent study. Using the 2015 National Health Interview Survey, researchers developed a Bayesian multinomial latent class model for arthritis surveillance based on doctor-diagnosed arthritis, joint symptoms, and whether symptom duration exceeded 3 months. They found:

• Of 33,672 participants, 19.3% of men and 16.7% of women aged 18 to 64 years affirmed joint symptoms without doctor-diagnosed arthritis; proportions were 15.7% and 13.5%, respectively, for those aged ≥65 years.
• The measurement error-adjusted prevalence of arthritis was 29.9% in men 18 to 64, 31.2% in women 18 to 64, 55.8% in men ≥65, and 68.7% in women ≥65.
• Arthritis affected 91.2 (of 247.7; 36.8%) million adults in the US in 2015, which included 61.1 (of 199.9; 30.6%) million persons between 18 and 64.
• The prevalence estimate is 68% higher than the previously reported arthritis national estimate.