This presentation is part of: Poster Session - Public Health; Methodological Advances
PREVALENCE AND COST IMPLICATIONS OF CHANGING DEFINITIONS FOR CHD RISK FACTORS
Robert Kaplan, PhD and Theodore Ganiats, MD. UCSD School of Medicine, 9500 Gilman Drive, Family and Preventive Medicine, La Jolla, CA
Purpose: Disease is often characterized as binary. A “diagnosis” is either present or absent. For most conditions, however, there is a spectrum of illness, and the definition of disease is based on a value (threshold) along a continuum. Sometimes the patient gets a very abnormal test value early in the disease, however for many diseases the patient slowly progresses from ‘normal’ to ‘borderline’ to abnormal. In order to give patients the benefit of early treatment, there has been a trend toward identification of disease earlier in the process by moving thresholds downward. We evaluated recent guidelines that lowered thresholds by defining prehypertension (SBP >120 mmHg), impaired fasting glucose (plasma glucose >100 mg/dl) and mild hypercholesterolemia (LDL >100 mg/dl) Method: Data from the third National Health and Nutrition Examination Survey (NHANES-III) were used to estimate the prevalence of prehypertenstion, impaired fasting glucose, and mild hypercholesterolemia in the US population age 50 years or older. Results: We estimate that 37% of the 62 million Americans age 50 or older have fasting glucose levels greater than 100 mg/dl. Further, nearly 40% of the population have systolic blood pressures greater than 120 mmHg. Nearly three quarters of the population (73%) have LDL cholesterol levels greater than 100 mg/dl. According to this preliminary analysis, 97% of American adults age 50 or older have at least one of the three conditions. Conclusions: Changes in diagnostic thresholds significantly expand the market for health care. Our analysis suggests that virtually the entire population of adults older than age 50 are eligible for a diagnosis (and potential intervention) under the new definitions of just three conditions. These changes in diagnostic thresholds are likely to have profound impacts on the costs of health care, but their effects upon population health have not been comprehensively evaluated.
