Original Research

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

Journal of Clinical Outcomes Management. 2014 January;21(1)

References

1. Centers for Disease Control and Prevention. National diabetes fact sheet: national estimates and general information on diabetes and prediabetes in the United States, 2011. Atlanta: US Department of Health and Human Services, Centers for Disease Control and Prevention, 2011.

2. Narayan KM, Boyle JP, Thompson TJ, et al. Lifetime risk for diabetes mellitus in the United States. JAMA 2003;290:1884–90.

3. McWilliams JM, Meara E, Zaslavsky AM, Ayanian JZ. Differences in control of cardiovascular disease and diabetes by race, ethnicity, and education: U.S. trends from 1999 to 2006 and effects of Medicare coverage. Ann Intern Med 2009;150:505–15.

4. Vouri SM, Shaw RF, Waterbury NV, et al. Prevalence of achievement of A1c, blood pressure, and cholesterol (ABC) goal in veterans with diabetes. Manag Care Pharm 2011;17:304–12.

5. Kirk JK, Bell RA, Bertoni AG, et al. Ethnic disparities: control of glycemia, blood pressure, and LDL cholesterol among US adults with type 2 diabetes. Ann Pharmacother 2005;39:1489–501.

6. American Diabetes Association. Standards of medical care in diabetes–2006. Diabetes Care 2006;29(Suppl 1):S4–S42.

7. American Diabetes Association. Standards of medical care in diabetes–2012. Diabetes Care 2012;35(Suppl 1):S11–S63.

8. Casagrande SS, Fradkin JE, Saydah SH, et al. The prevalence of meeting A1C, blood pressure, and LDL goals among people with diabetes, 1988-2010. Diabetes Care 2013;36:2271–9.

9. American Diabetes Association. Standards of medical care in diabetes–2013. Diabetes Care 2013;36(Suppl 1):S11–S66.

10. Schellenberg ES, Dryden DM, Vandermeer B, et al. Lifestyle intervention for patients with and at risk for type 2 diabetes: A systematic review and meta-analysis. Ann Inten Med 2013;159:543–51.

11. Hoerger TJ, Segel JE, Gregg EW, Saaddine JB. Is glycemic control improving in US adults? Diabetes Care 2008;31:81–6.

12. Inzucchi SE, Bergenstal RM, Buse JB, et al. Management of hyperglycemia in type 2 diabetes: a patient-centered approach. Diabetes Care 2012;35:1364–79.

13. Kirk JK, Strachan E, Martin CL, et al. Patient characteristics and process of care measures as predictors of glycemic control. J Clin Outcomes Manag 2010;17:27–30.

14. Chopra I, Kamal KM, Candrilli SD. Variations in blood pressure and lipid goal attainment in primary care. Curr Med Res Opin 2013;29:1115–25.

15. Jamerson K, Weber MA, Bakris GL, et al. Benazepril plus amlodipine or hydrochlorothiazide for hypertension in high-risk patients. N Engl J Med 2008;359:2417–28.

16. Grossman E. Blood pressure: the lower, the better. The con side. Diabetes Care 2011;34:S308–12.

17. Cushman WC, Evans GW, Byington RP, et al. Effects of intensive blood pressure control in type 2 diabetes mellitus. N Engl J Med 2010;362:1575–85.

18. Appiah B, Hong Y, Ory MG, et al. Challenges and opportunities for implementing diabetes self-management guidelines. J Am Board Fam Med 2013;26:90–2.

19. Best JD, Drury PL, Davis TME, et al. Glycemic control over 4 years in 4,900 people with type 2 diabetes. Diabetes Care 2012;35:1165–70.

Methods

Setting

Data were obtained from an academic family medicine clinic in the southeastern United States. Approximately 56,000 patient visits to this clinic are conducted annually. Family medicine residents in training, fellows, faculty physicians, physician assistants, a nutritionist, and diabetes educators care for patients seen in this practice.

Data Collection

A cohort of patients was identified using the International Classification of Diseases, 9th Revision, Clinical Modification codes for type 2 diabetes. The cohort comprised patients with diabetes in 2006 and 2012 who made follow-up visits in both years.

The data from both time-points were obtained from electronic medical record (EMR) data capture and structured chart review. Two reviewers reviewed 10% of the charts for accuracy after the data was pre-populated from the EMR. The following data were obtained: demographic variables (patient age, gender, and race), height, weight, insurance, smoking status, A1C, LDL, and BP measurements, pharmacotherapy for glycemia, hypertension, and hyperlipidemia, and number of medications needed for control. For variables that had multiple measures, we calculated an average for the year.

The study protocol was approved by the Institutional Review Board at Wake Forest School of Medicine.

Statistical Analysis

Descriptive statistics were performed to compute means, standard deviations, frequencies, and percentages for demographic variables and for glycemia, BP, LDL includ-ing patient characteristics, diabetes outcomes, and pharmacotherapy medication variables. Paired t tests were used to assess for a difference at the level of the patient in the means of the A1C, BP, and LDL between the 2 study time-points (2-sided alpha = 0.05). The non-parametric McNemar test was used to assess for differences in the proportions of patients at the identified goal for A1C, LDL, and BP for 2006 and 2012.

Results

The longitudinal cohort population consisted of 891 patients, 49.5% white and 48.1% African American, with a mean age of 57.9 years ( Table 1 ). The cohort represented 63.7% (891/1398) of the baseline population of patients with diabetes in 2006. Over half of the patients were female and the majority of the sample was overweight or obese. At baseline, almost the entire cohort had some type of insurance including private, Medicare, Medicaid, or a combination.

The number of visits per patient was 5.9 in 2006 and 5.3 in 2012. A1C remained constant between 2006 and 2012 (mean 7.6% vs. 7.7%, ± 1.8) along with body mass index (BMI), while mean LDL cholesterol significantly decreased from 109 ± 36.4 mg/dL in 2006 to 98.8 ± 40.4 mg/dL in 2012 ( Table 2 ). Mean systolic BP marginally increased over the 6-year period from 131.5 ± 14.2 to 134.8 ± 16.1 mm Hg with diastolic BP remaining constant.

The percentage of patients achieving the less stringent A1C goal of < 8% comprised over 50% of the population at both time points; however, compared with 2006, in 2012 there was a lower percentage of patients at the more stringent A1C target of < 7% (43.2% vs. 39.6%). The percentage of patients achieving goal for systolic BP was significantly decreased to 38.6% in 2012 versus 46.5% in 2006 (Table 2). However, the proportion of patients with controlled diastolic BP rose significantly from 70% to 77.6%. The number of patients achieving goal LDL (< 100 mg/dL) increased from 43.5% in 2006 to 58.6% in 2012.