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Optimal Management of Diabetes Among Overweight and Obese Adults | Page 2

Published Online: January 20, 2014
Denison S. Ryan, MPH; Karen J. Coleman, PhD, MS; Jean M. Lawrence, ScD, MPH, MSSA; Teresa N. Harrison, SM; and Kristi Reynolds, PhD, MPH
After adjusting for age, sex, race/ethnicity, income, number of comorbidities, and number of healthcare encounters, overweight and obese individuals were more likely to have all 4 screening measures (A1C testing, retinal examination, nephropathy screening, and  lipid screening) compared with their healthy-weight counterparts (Figure). The odds of having a retinal examination, however, did not consistently increase with increasing BMI (P for trend = .4410). Of note, the adjusted odds ratios (ORs) (95% confidence interval  [CI]) of nephropathy screening in overweight and obese class I, II, and III individuals compared with healthy-weight individuals were 1.17 (1.08-1.27), 1.44 (1.32-1.57), 1.62 (1.48-1.78), and 1.84 (1.66-2.04), respectively (P for trend <.0001). After adjustment, overweight and obese individuals were less likely to have optimal glycemic control (A1C <7% [<53 mmol/mol]) and BP control (<130/80 mm Hg) than their healthy-weight counterparts. In contrast, LDL-C control consistently increased across BMI categories, with class III obese individuals being more likely (OR = 1.23; 95% CI, 1.17-1.29) to achieve goal compared with their healthy-weight counterparts.

DISCUSSION

Among a diverse population of individuals with diabetes, our findings suggest that BMI was not a barrier to care for recommended screenings and examinations. We found that those individuals who were overweight and obese were more likely than their healthy-weight counterparts to have the recommended screening tests and examinations performed but were less likely to have their  glucose and BP controlled. Interestingly, we found the opposite for LDL-C control, which increased with increasing BMI.

Our findings are similar to those of several other studies; however, those studies did not exclusively include individuals with diabetes. Data from the California Men’s Health Study demonstrated that overweight and obese men were significantly more likely to have their glucose, cholesterol, and triglycerides tested regardless of whether they had diabetes.23 In the National Ambulatory  Medical Care Survey, obese participants were more likely to receive glucose and A1C testing, although it is not known what  proportion of these patients had diabetes.24 In a quality-of-care study among Medicare beneficiaries and recipients of Veterans  Health  Administration healthcare services, a higher BMI was associated with  increased odds of receiving A1C testing and lipid screening among patients with diabetes.16 A study among primary care patients examining diabetes and lipid screening rates found that higher BMI predicted higher screening rates for triglycerides, high-density lipoprotein cholesterol, LDL-C, and A1C; however, only 10% of this study population had diabetes.25

None of these aforementioned studies assessed the HEDIS-recommended control measures for diabetes care. To our knowledge, only 1 study to date has examined control rates. Rose and colleagues26 found that among nearly 50,000 individuals over an 18-month period, obese individuals were less likely to have good control of BP, LDL-C, and fasting glucose compared with healthy-weight individuals.

Despite evidence that overweight and obese individuals may avoid seeking healthcare services due to stigmatization, those with the added burden of chronic disease such as diabetes seek medical care more frequently,27 thus giving healthcare providers additional opportunities to perform screening examinations and tests. However, since retinal examinations are performed by ophthalmologists outside the primary care setting, increased use of healthcare services among individuals with a chronic disease may not extend to retinal examinations, thus potentially explaining the low screening rates we found for this measure. The high rates of nephropathy screening among obese patients in our study may be related to the high prevalence of nephropathy among people with diabetes and the severity of treatment for end-stage renal disease. Additionally, obesity is a possible risk factor for nephropathy.28

Similar to Rose and colleagues,26 we found weight-related differences for BP control in our study. We also found weight-related differences in A1C control. These findings are important because controlling BP and A1C can reduce the risk of microvascular complications such as nephropathy and cardiovascular disease among persons with diabetes.8 The unexpected finding of increased lipid control with increasing BMI may be due to the ADA recommendation of statin therapy regardless of lipid levels for patients with  diabetes who have cardiovascular disease or 1 or more risk factors for cardiovascular disease.8 Additionally, obese individuals  with elevated LDL-C from a subset of the Framingham Offspring and Third Generation cohorts were found to be more likely to be treated with lipid-lowering agents.5 

Although we found higher screening rates among overweight and obese individuals, the lower rates of glycemic control and BP control suggest that these patients may need additional encouragement and tools to achieve good control. Provider-led interventions to achieve BP control, however, have shown mixed results.29 Promising results were seen with nurse-led interventions using structured algorithms to improve BP control in people with diabetes.30 Similar nurse-led interventions could be implemented to improve glycemic control and BP control among patients with diabetes. Home BP monitoring and automated telephone interventions have proved to be effective at reducing BP and blood glucose levels and may be cost-effective strategies at the population level.31-33 Moreover, the pharmacist-led home BP monitoring program achieved greater impact among participants with diabetes.32

Several limitations of these analyses should be considered. The main limitation is that we only included individuals with a recorded BMI. It is possible that individuals without a documented BMI differ from the study population. However, the number of individuals missing height and weight measurements to calculate BMI was only 2.3% of the sample (n = 3901). Due to the fact that this study was conducted using data from 1 integrated healthcare system in 1 region of the country, our results may not be generalizable to  populations in other geographic areas or in other types of healthcare delivery systems. The large sample size allowed for the detection of small, statistically significant differences. While these differences may not be clinically relevant on an individual level,  they are indicative of a larger trend on a population level. Further, KPSC has laboratory facilities in many of its medical centers, and  results are available online for review by members after the tests are completed. This convenience and availability of results may increase the overall likelihood of patients completing recommended blood tests. Finally, this study adjusted for but did not assess the influence of race/ethnicity on screening performance or control rates. However, 1 study found that race/ethnicity was not consistently associated with lower screening rates in black and Hispanic populations compared with whites.34

The strengths of this study include its large and racially/ethnically diverse composition that is reflective of the general population in southern California, a broad age range, and the use of information in the EHR rather than self-reported BMI data. Misclassification errors can result with the use of self-reported BMI data because individuals are likely to underreport weight and to over-report height.35

Among patients with diabetes enrolled in a large integrated managed care organization, we found weight-related disparities in A1C and BP control. These findings support the need for increased attention by patients, providers, and healthcare systems to improving BP and glycemic control among overweight and obese patients with diabetes. This study also highlighted the need for better retinal examination performance across all BMI categories, including for healthy-weight individuals. Future studies should focus on identifying modifiable healthcare system, provider, and patient factors associated with health outcomes in overweight and obese individuals with diabetes.

Take-Away Points

This study highlights the need for increased attention by patients, providers, and healthcare systems to improving blood pressure and glycemic control among overweight and obese patients with diabetes.
  • Overweight and obese individuals were more likely than their healthy-weight counterparts to have glycated hemoglobin (A1C) testing, retinal examinations, and lipid and nephropathy screenings performed.
  • Among those tested or screened, overweight and obese individuals were less likely to have their A1C and blood pressure controlled; low-density lipoprotein cholesterol control increased as body mass index increased.
Author Affiliations: From Kaiser Permanente Southern California (DSR, KJC, JML, TNH, KR), Pasedena, CA.

Funding Source: The research was funded by Southern California Permanente Medical Group.

Author Disclosures: The authors (DSR, KJC, JML, TNH, KR) report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.

Authorship Information: Concept and design (KJC, KR); acquisition of data (DSR, KJC, JML, TNH, KR); analysis and interpretation of data (DSR, KJC, JML, TNH, KR); drafting of the manuscript (DSR, KJC, JML, TNH, KR); critical revision of the manuscript for important intellectual content (JML, TNH, KR); statistical analysis (DSR, THN); technical, or logistic support (THN, KR).

Address correspondence to: Kristi Reynolds, PHD, MPH, Department of Research and Development, Kaiser Permanente Southern California, 100 S Los Robles, 2nd Fl, Pasadena, CA 91101. E-mail: Kristi.Reynolds@KP.org.
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