Objective: Controlling hypertension (HTN) in patients with diabetes mellitus (DM) can reduce complications such as nephropathy, cerebrovascular disease, and cardiovascular disease. As part of a quality improvement project with a managed care organization (MCO), we evaluated blood pressure (BP) control relative to the type of drug therapy for patients with type 1 or type 2 DM who were identified from pharmacy claims for antihyperglycemic drug therapy.
Methods: Pharmacy claims for antihyperglycemic drugs, including insulin, were used to identify a random sample of commercial members in an MCO comprising 30 health plans across the United States. Retrospective medical record review was conducted in October 2003 to collect data from 4,814 patient charts. BP goal attainment according to The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) guidelines was determined for each patient from the most recent BP reading documented in the medical chart.
Results: The distribution by type of DM was 21.0% (n = 1,011) for type 1, 75.7% (n = 3,644) for type 2, and 3.3% (n = 159) for cases not documented in the medical chart. Excluding 590 charts (12.3%) without BP values, there were 1,328 of 4,224 DM patients (31.4%) at JNC 7 BP goal (< 130/80 mm Hg). Of the 1,328 patients at JNC 7 BP goal, 577 (43.4%) were at JNC 7 BP goal with no drug therapy. Excluding the 577 patients who did not require drug therapy to reach JNC 7 goal, 751 (20.6%) of the remaining 3,647 patients who required antihypertensive drug therapy were at JNC 7 BP goal, and 788 (21.6%) received no antihypertensive drug therapy. For the population of 4,224 DM patients with a BP value recorded in the chart, application of the lower BP goals in the JNC 7 guidelines reduced the proportion with controlled BP to 31.4% (1,328/4,224) from 42.6% (1,799/4,224) according to the former JNC 6 guidelines (P < 0.01). The proportion of DM patients with HTN was 59.6% (n = 2,870), and 28.4% (n = 814) of these patients were not taking either an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin receptor blocker (ARB). There were 704 patients with albuminuria or nephropathy (14.6%), of which 35.4% (n = 249) were not taking either an ACEI or an ARB, preferred therapy in these patients.
Conclusion: In this population of MCO members with DM for whom a BP value was recorded in the medical chart, 13.7% met JNC 7 BP goal with no antihypertensive drug therapy. For the patients with DM who received antihypertensive drug therapy and had a BP value recorded in the medical chart, only 26.3% were at JNC 7 BP goal. The application of JNC 7 guidelines significantly reduced the proportion of DM patients at target BP goal from 42.6%% to 31.4%