With the increasing number of patients with multiple conditions, cardiologists now must factor in comorbidities in their treatment plans. But is simultaneous control of diabetes, high blood pressure and high cholesterol levels feasible? Not often and not easily, researchers reported online July 31 in Circulation: Cardiovascular Quality and Outcomes.
Emily B. Schroeder, MD, PhD, of the Institute for Health Research at Kaiser Permanente Colorado in Denver, and colleagues looked at three conditions that commonly can occur in a single patient: diabetes mellitus, hypertension and hyperlipidemia. For their retrospective cohort study, they identified 5,269 patients at Denver Health and 23,458 at Kaiser Permanente with the three conditions from 2000 through 2008. Denver Health is an inner city integrated healthcare system while Kaiser Permanente is a large managed care organization.
Patients were followed for a median of at least four years to assess the incidence of concurrent diabetes mellitus, hypertension and hyperlipidemia; the proportion who maintain simultaneous control of the three conditions; and whether changing target goals affected control. The researchers also looked at risk factor characteristics and differences between the two study groups.
The primary outcome was the occurrence of simultaneous control of glycosylated hemoglobin (HbA1c), systolic and diastolic blood pressure and low-density lipoprotein (LDL) cholesterol. They applied the American Diabetes Association’s 2002 guideline targets for risk factor control: HbA1c less than 7 percent, blood pressure (BP) less than 130/80 mm Hg and LDL cholesterol less than 100 mg/dL.
Only 16.2 percent of the Denver Health group and 30.3 percent of the Kaiser Permanente group achieved simultaneous control of all three risk factors. The patients struggled to maintain control; 90 days after achieving control, 23 percent of the Denver Health group and 39 percent of the Kaiser Permanente group lost but then regained control, while 64 percent of the Denver Health group and 56 percent of the Kaiser Permanente group lost and never regained control. After achieving control, only 13 percent of the Denver Health group and 5 percent of the Kaiser Permanente group maintained control.
When the researchers applied a less stringent risk factor cutoff point, twice as many patients achieved simultaneous control. They found that medication adherence was a strong predictor of achieving simultaneous control and that the predictors were similar for the two groups.
“Our study illustrates that when continuous measurements (such as HbA1c, BP, and LDL cholesterol) are transformed into dichotomous threshold-based measures, relatively small differences in cut points can have large effects on conclusions concerning quality of care,” Schroeder and colleagues wrote.
The authors acknowledged that finding the appropriate threshold is challenging, with possible consequences occurring in a variety of scenarios.
“Using high threshold goals ensures that the goals are appropriate for almost all individuals and focuses attention on individuals who are the furthest from the optimal levels and who therefore have the most to gain,” they wrote. “However, it does not encourage the healthcare system to help most individuals achieve optimal levels. In contrast, using stricter threshold goals means the risks of the resulting aggressive treatment will exceed the potential benefits for some individuals.”
They observed that elevated BP appeared to be the tipping point at which most patients lost control, possibly because of a higher frequency of BP testing and more BP variability within each patient. They attributed the higher rate of control seen in the Kaiser Permanente group to patient level and system level factors.
The two health systems used slightly different inclusion and exclusion criteria, Schroeder et al noted, and measurements were variable with some data missing.
But they wrote that lessons may be gleaned from those patients who achieved success. “Efforts to understand the strategies that such individuals, particularly those with durable control, use to balance the demands of their multiple health conditions may help define interventions to improve self-care and health outcomes among the increasing population of individuals with multiple, chronic health conditions,” they concluded.