The time elapsed since a primary care physician's last board certification correlates with a decline in the quality of care provided to patients, according to a study published by researchers at Boston's Brigham and Women's Hospital. The study included 8,127 hypertensive patients with diabetes who had a high blood pressure reading documented in their records at least once between 2000 and 2005. The team analyzed the temporal relationship between board certification and treatment intensification, defined as an increase in dose, a change from one drug to another or the addition of a new drug.