Daniel J. Cox

Evaluating Clinical Accuracy of Systems for Self-Monitoring of Blood Glucose

Although the scientific literature contains numerous reports of the statistical accuracy of systems for self-monitoring of blood glucose (SMBG), most of these studies determine accuracy in ways that may not be clinically useful. We have developed an error grid analysis (EGA), which describes the clinical accuracy of SMBG systems over the entire range of blood glucose values, taking into account 1) the absolute value of the system-generated glucose value, 2) the absolute value of the reference blood glucose value, 3) the relative difference between these two values, and 4) the clinical significance of this difference. The EGA of accuracy of five different reflectance meters (Eyetone, Dextrometer, Glucometer I, Glucometer II, Memory Glucometer II), a visually interpretable glucose reagent strip (Glucostix), and filter-paper spot glucose determinations is presented. In addition, reanalyses of a laboratory comparison of three reflectance meters (Accucheck II, Glucometer II, Glucoscan 9000) and of two previously published studies comparing the accuracy of five different reflectance meters with EGA is described. EGA provides the practitioner and the researcher with a clinically meaningful method for evaluating the accuracy of blood glucose values generated with various monitoring systems and for analyzing the clinical implications of previously published data.

Fear of Hypoglycemia: Quantification, Validation, and Utilization

Hypoglycemia can lead to various aversive symptomatic, affective, cognitive, physiological, and social consequences, which in turn can lead to the development of possible phobic avoidance behaviors associated with hypoglycemia. On the other hand, some patients may inappropriately deny or disregard warning signs of hypoglycemia. This study presents preliminary reliability and validity data on a psychometric instrument designed to quantify this fear: the hypoglycemic fear survey. The instrument was found to have internal consistency and test-retest stability, to covary with elevated glycosylated hemoglobin, and to be sensitive to a behavioral treatment program designed to increase awareness of hypoglycemia.

A Behavior Change Model for Internet Interventions

BackgroundThe Internet has become a major component to health care and has important implications for the future of the health care system. One of the most notable aspects of the Web is its ability to provide efficient, interactive, and tailored content to the user. Given the wide reach and extensive capabilities of the Internet, researchers in behavioral medicine have been using it to develop and deliver interactive and comprehensive treatment programs with the ultimate goal of impacting patient behavior and reducing unwanted symptoms. To date, however, many of these interventions have not been grounded in theory or developed from behavior change models, and no overarching model to explain behavior change in Internet interventions has yet been published.PurposeThe purpose of this article is to propose a model to help guide future Internet intervention development and predict and explain behavior changes and symptom improvement produced by Internet interventions.ResultsThe model purports that effective Internet interventions produce (and maintain) behavior change and symptom improvement via nine nonlinear steps: the user, influenced by environmental factors, affects website use and adherence, which is influenced by support and website characteristics. Website use leads to behavior change and symptom improvement through various mechanisms of change. The improvements are sustained via treatment maintenance.ConclusionBy grounding Internet intervention research within a scientific framework, developers can plan feasible, informed, and testable Internet interventions, and this form of treatment will become more firmly established.

Reduced Awareness of Hypoglycemia in Adults With IDDM: A prospective study of hypoglycemic frequency and associated symptoms

OBJECTIVE To prospectively evaluate the frequency and severity of hypoglycemic episodes in IDDM subjects who declare themselves to have reduced awareness of hypoglycemia, to validate their self-designations in their natural environment, and to determine objectively the presence or absence of autonomic and neuroglycopenic symptoms associated with their low blood glucose (BG) levels. RESEARCH DESIGN AND METHODS A total of 78 insulin-dependent diabetes mellitus (IDDM) subjects (mean age 38.3 ± 9.2 years; duration of diabetes 19.3 ± 10.4 years) completed two sets of assessments separated by 6 months. The assessments included reports of frequency and severity of low BG, symptoms associated with low BG, and a BG symptom/estimation trial using a hand-held computer (HHC). Diaries of hypoglycemic episodes were kept for the intervening 6 months. HbA1 levels were determined at each assessment. RESULTS Of the subjects, 39 declared themselves as having reduced awareness of hypoglycemia (reduced-awareness subjects). There were no differences between these reduced-awareness subjects and aware subjects with regard to age, sex, disease duration, insulin dose, or HbA1. During the HHC trials, reduced-awareness subjects were significantly less accurate in detecting BG < 3.9 mmol/l (33.2 ± 47 vs. 47.6 ± 50% detection, P = 0.001) and had significantly fewer autonomic (0.41 ± 0.82 vs. 1.08 ± 1.22, P = 0.006, reduced-awareness vs. aware) and neuroglycopenic (0.44 ± 0.85 vs. 1.18 ± 1.32, P = 0.004, reduced-awareness vs. aware) symptoms per subject. Prospective diary records revealed that reduced-awareness subjects experienced more moderate (351 vs. 238, P = 0.026) and severe (50 vs. 17, P = 0.0062) hypoglycemic events. The second assessment results were similar to the first and verified the reliability of the data. CONCLUSIONS IDDM subjects who believe they have reduced awareness of hypoglycemia are generally correct. They have a history of more moderate and severe hypoglycemia, are less accurate at detecting BG < 3.9 mmol/l, and prospectively experience more moderate and severe hypoglycemia than do aware subjects. Neither disease duration nor level of glucose control explains their reduced awareness of hypoglycemia. Reduced-awareness individuals may benefit from interventions designed to teach them to recognize all of their potential early warning symptoms.

Internet Interventions: In Review, In Use, and Into the Future

The provision of health care over the Internet is a rapidly evolving and potentially beneficial means of delivering treatment otherwise unsought or unobtainable. Internet interventions are typically behavioral treatments operationalized and transformed for Web delivery with the goal of symptom improvement. The literature on the feasibility and utility of Internet interventions is limited, and there are even fewer outcome study findings. This article reviews empirically tested Internet interventions and provides an overview of the issues in developing and/or using them in clinical practice. Future directions and implications are also addressed. Although Internet interventions will not likely replace face-to-face care, there is little doubt that they will grow in importance as a powerful component of successful psychobehavioral treatment. With the advancement of computer technologies over the past 20 years, a flood of new ways to communicate, provide, and deliver psychological treatments has emerged. The Internet has the ability to reach people all over the world and provide highly specialized psychological interventions otherwise not sought or obtainable. There is a new but growing literature on the use of the Internet as a means of delivering treatment. These Internet treatments are typically focused on behavioral issues, with the goal of instituting behavior change and subsequent symptom improvement. They are usually self-paced, interactive, and tailored to the user, and they make use of the multimedia format offered by the Internet. Individuals with computer and Internet access who use these treatments may also overcome many of the barriers to obtaining traditional care because they can seek such treatments at any time, any place, and often at significantly reduced cost. Clearly, people are using computers and the Internet in greater frequency and with the specific purpose of obtaining mental health information (see Crutsinger, 2000; Employment Policy Foundation, 2001; Pew Research Center, 2002; Rabasca, 2000). This new field of Internet interventions is only going to grow and expand. The benefits are vast, as there is the potential for greater numbers of people to receive more services than ever before. However, to meet this potential, Internet interventions, like any other treatment, must first demonstrate feasibility and efficacy through rigorous scientific testing. In this article we present a critical examination of the current state of the available literature focused on the development and testing of these types of interventions. In addition, issues that should be addressed when constructing Internet interventions are enumerated, followed by a discussion of possible future directions and implications for research and clinical practice.

Major developments in behavioral diabetes research.

Over the past decade, there has been a major increase in behavioral diabetes research. This review focuses on 6 areas: self-treatment, psychosocial impact, diabetes-specific assessment, psychological stress, weight loss intervention, and neuropsychological effects. There has been great progress in identifying factors that predict self-treatment behaviors and psychological adjustment. This research has produced a number of diabetes-specific assessment tools. Psychological stress appears to affect both the etiology and the control of diabetes, but underlying mechanisms remain unclear. Weight loss studies demonstrate the potential benefits of behavioral interventions for diabetes management. Both acute and chronic abnormalities in diabetic blood glucose cause neuropsychological impairments and may cause permanent deficits. The challenge for the next decade is to translate these findings into interventions that improve quality of life and physical well-being for individuals with diabetes.

Diabetes and behavioral medicine: the second decade.

Diabetes management depends almost entirely on behavioral self-regulation. Behavioral scientists have continued a collaboration with other health systems researchers to develop a holistic approach to this disease. The authors summarized the literature in 4 major areas: self-management of diabetes, psychosocial adjustment and quality of life, neuropsychological impact, and psychobehavioral intervention development. Progress made in each of these areas over the past decade is highlighted, as are important issues that have not yet received sufficient scientific attention. Emerging areas likely to become central in behavioral research, such as diabetes prevention, are introduced. The future of behavioral medicine in diabetes is also discussed, including topics such as the changing role of psychologists in diabetes care, the urgent need for more and better intervention research, the growing importance of incorporating a health system-public health perspective, and obstacles to the integration of psychobehavioral approaches into routine health care delivery.

Accuracy of Perceiving Blood Glucose in IDDM

Type I (insulin-dependent) diabetic individuals and health professionals often assume that the symptoms of extremely low or high blood glucose (BG) levels can be recognized and, consequently, appropriate treatment decisions can be based on symptom perception. Because no research has documented the validity of these assumptions, this study tested the ability to perceive BG concentration. Nineteen type I adults, experienced in self-monitoring of BG (SMBG), estimated their BG 40–54 times just before measurement of actual BG. This procedure was repeated under two conditions: (1) in the hospital (hospital condition) while connected to an insulin/glucose infusion system that artificially manipulated BG, leaving subjects only symptomatic, or internal, cues and (2) in the natural environment (home condition), where both internal and external cues, e.g., food and insulin consumption, were available. Estimates significantly correlated with actual BG for 7 of 16 subjects in the hospital condition and for 18 of 19 subjects in the home condition. Believed ability to estimate BG did not predict documented ability in either condition. An evaluation of the treatment significance of estimation errors showed that the majority of errors were relatively benign. The most common error affecting clinical outcome was estimated euglycemia when actual BG was hypoglycemic or hyperglycemic.

An Internet Intervention as Adjunctive Therapy for Pediatric Encopresis

This study evaluated the benefits of enhanced toilet training delivered through the Internet for children with encopresis. Twenty-four children with encopresis were randomly assigned to the Internet intervention group (Web) or no Internet intervention group (No-Web). All participants continued to receive routine care from their primary care physician. The Web participants demonstrated greater improvements in terms of reduced fecal soiling, increased defecation in the toilet, and increased unprompted trips to the toilet (ps<.02). Both groups demonstrated similar improvements in knowledge and toileting behaviors. Internet interventions may be an effective way of delivering sophisticated behavioral interventions to a large and dispersed population in a convenient format.

Long-Term Follow-Up Evaluation of Blood Glucose Awareness Training

OBJECTIVE Blood glucose awareness training (BGAT) has been found effective in teaching individuals with insulin-requiring diabetes to improve their ability to better recognize blood glucose (BG) fluctuations. This study investigated whether subjects who underwent BGAT a mean of 4.9 years previously were superior to past control subjects in terms of their ability to recognize BG fluctuations, and whether past BGAT subjects had fewer automobile crashes and lost work days and better glycosylated hemoglobin than control subjects. Additionally, the beneficial effects of providing booster training to past BGAT subjects also was evaluated. RESEARCH DESIGN AND METHODS This study followed up 28 past BGAT subjects. Half of these subjects (n = 14) received a simple booster-training program. Twelve previous control subjects also were evaluated. Booster subjects were given a BGAT diary to complete for 2 weeks before evaluation. Evaluation for all subjects included completion of a retrospective questionnaire on work and driving history, blood drawing for a glycosylated hemoglobin analysis, and having subjects estimate and measure their BG levels 50–80 times during a 3- to 4-week period during their daily routine. RESULTS At long-term follow-up, BGAT subjects had significantly fewer automobile crashes than control subjects. BGAT subjects receiving booster training were significantly more accurate at estimating their BG levels and were more aware of hypoglycemia. Post hoc analyses indicated that the ability to accurately estimate BG fluctuations correlated positively with follow-up glycosylated hemoglobin and the number of hypoglycemic and hyperglycemic symptoms participants demonstrated.Both BGAT and control subjects demonstrated significantly improved glycosylated hemoglobin relative to baseline measures. CONCLUSIONS These data suggest that BGAT has long-term benefits, which can be enhanced with booster training. Specifically, BGAT and simple booster training may result in reduction of severe hypoglycemic episodes and automobile crashes in the long term.