Physician volume linked to diabetes care quality, study finds

Data on more than 1 million adults with diabetes indicated that higher ambulatory volume overall was associated with lower rates of appropriate eye exams, HbA1c testing, and LDL cholesterol testing, among other results.


Busier primary care practices were associated with lower-quality diabetes care, but practices with more experience treating diabetic patients were associated with higher-quality diabetes care, according to a recent study.

Researchers performed a cohort study using linked population-based administrative health care data in Ontario, Canada, to examine whether primary care physician volume was related to quality of diabetes care. Volume was measured as overall ambulatory volume, calculated as number of a physician's outpatient visits divided by days worked during the study period, and diabetes-specific volume, defined as the number of diabetic patients for whom a physician was the usual primary care clinician.

Six indicators of care quality were measured over 2 years in 3 categories: appropriate disease monitoring and testing in the 2 years after the index date (≥1 eye exam, ≥3 HbA1c tests, and ≥1 LDL cholesterol test), prescribing of appropriate medications (angiotensin-converting enzyme [ACE] inhibitors or angiotensin-receptor blockers [ARBs] and statins), and adverse clinical outcomes (ED visits for hypo- or hyperglycemia). The study results were published online on Dec. 13 by Annals of Internal Medicine.

Data on 1,018,647 adults with diabetes, cared for by 9,014 primary care physicians in 2011, were included in the study. The researchers found that higher ambulatory volume overall was associated with lower rates of appropriate eye exams, HbA1c testing, and LDL cholesterol testing. Patients from practices with higher overall volume were also less likely to fill prescriptions for ACE inhibitors or ARBs and for statins. Higher diabetes-specific volume, however, was associated with better care on all 6 of the quality indicators.

The authors noted that data on prescriptions were available only for patients ages 65 or older, that they looked at only a particular set of quality indicators, and that they could not adjust for patient-level clinical factors, such as body mass index. However, they concluded that while primary care physicians with busier practices appeared to deliver lower-quality diabetes care, physicians who had more direct diabetes care exposure delivered better-quality diabetes care.

This finding could have important implications for future research and health system planning, the authors said. “Future policies to improve quality of diabetes care may offer peer support and mentoring, point-of-care support, or enhanced specialty-primary care interactions to primary care physicians with low diabetes-specific volume,” they wrote.

An accompanying editorial said that the study authors provide an “important contribution to our understanding of the influences on quality of diabetes care by [primary care physicians], but as with many strong studies, they raise as many questions as they answer.” The editorialists pointed out that process measures only approximate clinical outcomes and that it is not clear whether outcomes between groups in the study varied substantially. In addition, they said, further evidence is needed on the potential effectiveness of any intervention to improve diabetes care. “Without additional effectiveness studies, the introduction of any innovation into [primary care physician] practices could have unforeseen consequences on workflow,” the editorialists wrote.