Outcomes and Medication Use in a Longitudinal Cohort of Type 2 Diabetes Patients, 2006 to 2012

Table 3 shows achievement of BP < 130/80 by anti-hypertensive regimen. The majority of the hypertensive regimens included the use of an ACEI or an ARB, with overall BP control achieved in at least 45% of patients. The highest BP control (49%) was achieved in the diuretic and CCB–containing regimens without an ACEI or ARB, represented by a smaller group of patients (n = 65). There were 32 patients whose hypertension was controlled without antihypertensive therapy. Ninety-three percent of the cohort had data for evaluation in both years.

Discussion

Despite the availability of evidence-based guidelines and vast knowledge about microvascular and macrovascular complications due to diabetes, clinical goals for diabetes outcomes are not being routinely achieved in practice. More work is needed to achieve national standards of care. NHANES data from 2007 to 2010 revealed that 52.5% of patients with diabetes achieved an A1C of < 7% while 51.1% had a BP < 130/80 and 56.2% had an LDL < 100 mg/dL [8].

Improvement in LDL cholesterol was seen in the current study, and A1C remained constant during the 6-year time period. While mean A1C, BP, and LDL measurements were close to ADA target goals, a smaller proportion of patients were controlled in 2012 compared with 2006. Hoerger and colleagues [11] found using NHANES data 1999 to 2004 that mean A1C levels significantly declined over time, with 55.7% (up from 36.9%) achieving an A1C of < 7% by 2004  [11]. In our sample of patient with diabetes, only 39.6% were at A1C goal in 2012; 8.2% (61/742) achieved control with no medications.

Metformin is first-line therapy according to ADA recommendations. Most regimens in our study included this drug, with a large percentage of patients with controlled A1C taking this very affordable agent [12]. The combination regimens with metformin plus another oral therapy or 2 oral drugs with insulin resulted in a higher percentage of patients controlled  compared to metformin or insulin monotherapy. From our previous chart review [13] of the entire practice of patients with diabetes (n = 1398) from 2006, A1C control was similarly achieved in patients taking insulin (31% vs. 33%) or insulin combinations (19% vs. 20%) from 2006 to 2012, respectively.

For LDL cholesterol control, 9.7% (57/588) of the cohort used no medications to reach goal. Statin use predominated, with 60% of the cohort reaching goal with a single statin agent. Approximately one-third (175/588) of evaluable patients were on  more than 1 cholesterol medication, and about half of these (53%) reached goal. Over the 6-year period, atorvastatin become available generically, which may have impacted the number of patients able to use this statin. Compared with a recent literature review over a 12-year period of LDL attainment in primary care [14], the results of our study show equivalent or better LDL goal achievement among patient with diabetes.

The majority of the patients received an ACEI or ARB. There were a comparable number of patients controlled with ACEI or ARB with a diuretic, versus an ACEI or ARB with a diuretic and CCB. Large-scale clinical trials have shown that using an ACEI or ARB in combination with a CCB is superior to a hydrochlorathiazide-based combination for reducing risk of major cardiovascular events [15]. The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial showed that serious adverse events attributed to antihypertensive treatment occurred more frequently in the intensive therapy group (< 120/80) than in the standard therapy (< 140/80) group [16]. The stringent systolic BP goal in accord was accomplished using 3.4 medications. Aggressive lowering of BP may be dangerous in patients with diabetes and there is no benefit found in many large-scale studies [17]. The 2013 ADA goal for BP is now < 140/80 mm Hg, and while our data show that a significant increase in BP was seen over a 6-year period, the number of medications needed to control BP will likely be lower with the new ADA target and potentially safer.

In our cohort, over the 6-year period there was an increase in the number of medications needed to achieve glycemic, BP, and LDL goals. During this time, there were no major changes in the way the patients received care in the clinic environment. We cannot comment on whether lifestyle changes or diabetes education may have impacted the need for increased medication use. Limitations to this study include the unavailability of  A1C (17%) and LDL (34%) data at both time points for every patient, inability to verify insurance data for the 2012 time period, and that the data are from a single practice. We also were unable to determine the duration of diabetes diagnosis due to a change in electronic medical record systems and lack of full documentation by providers.

These findings suggest that as patients live longer with type 2 diabetes, they will need increasing numbers of medications to achieve standard of care goals. Research has shown that there are challenges in implementing diabetes guidelines in primary care, including potential inaccuracies contained in electronic patient health information, inadequate coordination among health care providers, physician lack of awareness of guidelines, and clinical inertia [18]. As shown in the current study and other research, intensification of traditional therapies for glycemic control can sustain target outcomes without the risk of significant weight gain [19].

The chronic condition of diabetes is associated with medical complications as well as challenges for providing optimal care, despite advances in pharmacotherapy. As more medications are added to a patient’s regimen, adherence can become challenging. The cost of medications also warrants consideration. Research is needed to understand the impact on quality of life, cost of care, and outcomes of these regimens as well as whether lifestyle modifications can impact the number of medications needed by individual patients. The current study indicates that overall outcome control for A1C and BP can be sustained and significantly decreased for LDL cholesterol using multiple medications with the primary agent being a statin drug.

Acknowledgements: We would like to thank Drs. Elizabeth Strachan and Madhavi Peechara for their past contributions and diligence in the original chart review.

Corresponding author: Julienne K. Kirk, PharmD, CDE, Wake Forest School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157-1084, jkirk@wakehealth.edu.

Financial disclosures: None.

Author contributions: conception and design, JKK, KL, RWL; analysis and interpretation of data, JKK, SWD, KL, CAH, RWL; drafting of article, JKK, KL, RWL; critical revision of the article, JKK, KL, CAH; provision of study materials or patients, JKK, SWD; statistical expertise, SWD; administrative or technical support, CAH; collection and assembly of data, JKK, KL, CAH.