Health Economics, Policy and Law


Understanding recent increases in chronic disease treatment rates: more disease or more detection?

David H. Howarda1 c1, Kenneth E. Thorpea1 and Susan H. Buscha2

a1 Department of Health Policy and Management, Rollins School of Public Health, Emory University, Atlanta, GA, USA

a2 Division of Health Policy and Administration, Yale School of Public Health, Yale University, New Haven, CT, USA


The proportion of the population treated for major medical conditions, including diabetes, cancer and mental illness, increased rapidly during the 1990s. We document the magnitude of these increases and use a model of prevalence to identify three potential causes: increased clinical incidence of disease, longer survival times among persons with chronic illnesses and increased detection. We present a series of analyses to evaluate the contribution of each factor. We find that increases in obesity explain a large proportion of the increase in treatment rates for conditions closely linked to obesity (e.g. diabetes). We provide some evidence that increases in treated prevalence unexplained by changes in the underlying clinical incidence of disease are driven by increased detection and treatment of patients with ‘subclinical’ illness.


c1 Correspondence to: David Howard, Department of Health Policy and Management, Emory University, 1518 Clifton Road NE, Atlanta, GA 30322, USA. E-mail: