This measure examines BMI changes using 3 Performance Rates: Performance Rate 1: The percentage of patients 18 years and older whose most recent BMI has decreased by at least 5 from the highest level to the most recent BMI out of all patients with at least 2 BMI levels in the measurement year or year prior to the measurement year with at least one BMI greater than or equal to 35. Performance rate 2: The percentage of patients 18 years and older whose most recent BMI has increased by at least 5 from the lowest level to the most recent BMI, out of all patients with at least 2 BMI levels in the measurement year or year prior to the measurement year with at least one BMI less than 35. Performance Rate 3: The difference between Performance Rate 1 and Performance Rate 2, divided by the total denominator. Performance Rate 3 is the final performance rate for this measure.