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An additional cause of health care disparities: the variable clinical decisions of primary care doctors



Dr John McKinlay

New England Research Institutes (NERI)

9 Galen Street

Watertown, MA 02472




Rationaleaims and objectives

Decades of work on health disparities have culminated in identification of three contributors to variability in diagnosis and management of disease: (i) patient attributes; (ii) doctor's characteristics; and (iii) organizational factors. Understanding the relative influence of different contributors to variability in diagnosis and management of diabetes is important to improving quality and reducing disparities. This study was designed to examine the influence of patient, provider and organizational factors on the diagnosis and management of a major chronic disease – diabetes.


A factorial experiment using video vignettes was conducted among n = 192 primary care doctors. Doctors were interviewed after viewing vignettes of (1) a ‘patient’ with symptoms strongly suggestive of diabetes and (2) an already diagnosed diabetes ‘patient’ with emerging peripheral neuropathy.


A total of 60.9% of doctors identified diabetes as the correct diagnosis, with significant variations depending on the patients’ race/ethnicity. Many doctors offered competing diagnoses with high levels of certainty. For the ‘patient’ with emerging peripheral neuropathy, 42.2% of doctors would do all essential components of a foot examination, while 21.9% would do none.


That half of all diabetes in the United States remains undiagnosed is unsurprising given only 60.9% of doctors would diagnose it when the condition is strongly suggested, and nearly one-quarter suspecting diabetes would not order tests necessary to confirm it. The diagnosis of diabetes is significantly influenced by a patient's race/ethnicity, and clinical management (specifically for foot neuropathy) is influenced by patient socio-economic status (SES), doctor's gender and access to clinical guidelines.