Accuracy Of Blood Glucose Estimation Research Articles

Using error grid analysis to assess blood glucose estimation accuracy in adolescents with type 1 diabetes

ABSTRACTDespite an increase in adolescents’ use of type 1 diabetes (T1D)-related technology to aid in blood glucose (BG) management and insulin administration, adolescents with T1D often estimate their current BG levels to inform management decisions. The present study used error grid analysis to explore adolescents’ BG estimation accuracy and examined the relationship between estimation accuracy and diabetes technology use. Fifty-five adolescents diagnosed with T1D completed the study. Participants estimated their BG level before checking it with a meter, and described their use of diabetes technology. Error grid analyses indicated that most estimates did not have “clinically serious” implications; however, raw estimations differed from actual BG values by an average of 33%. Participants who reported checking their BG more frequently per day with a meter made more accurate BG estimations as measured by both error grid analysis and percentage deviations. Findings underscore the importance of encouraging adolescents with T1D to engage in BG monitoring often. Increased BG monitoring with a meter may increase adolescents’ ability to accurately estimate their BG values. Thus, advanced BG monitoring technology should be used in conjunction with meter checking. Examining BG estimation accuracy with error grid analysis holds promise for better understanding self-management practices.

Blood glucose estimations in adolescents with type 1 diabetes: predictors of accuracy and error.

To examine predictors of blood glucose (BG) estimation accuracy and errors in adolescents with Type 1 diabetes. Seventy-eight adolescents (ages 11-19) rated their physical symptoms and estimated their BG prior to conducting daily BG tests. BG estimation data were subject to an error grid analysis. Hierarchical regression was used to identify predictors of BG estimation accuracy and errors. The average participant made accurate BG estimations 37% of the time and clinically relevant BG estimation errors 24% of the time. Girls and older adolescents had higher BG estimation accuracy rates and lower BG estimation error rates than boys and younger adolescents. Higher BG variability was also associated with increased BG estimation errors. Although boys, younger adolescents, and those with higher BG variability showed higher BG estimation error rates, most participants showed low rates of BG estimation accuracy and high rates of BG estimation error. Health providers may underestimate the frequency of inappropriate self-treatment as a result of patient difficulty in estimating BG accurately.

Detection of symptoms by adolescents and young adults with type 1 diabetes during experimental induction of mild hypoglycemia: role of hormonal and psychological variables.

To identify hormonal, psychological, and demographic predictors of symptom detection and accuracy of blood glucose estimation during mild hypoglycemia in adolescents and young adults with type 1 diabetes. During an insulin-glucose clamp study, 53 adolescents and 19 young adults estimated blood glucose levels and reported symptoms at euglycemia and after 30 min of mild hypoglycemia (3.3 mmol/l). Epinephrine and pancreatic polypeptide were measured, and both change in anxiety level during hypoglycemia and baseline level of anxiety were measured with the Spielberger Anxiety Inventory. Elevated levels of anxiety during euglycemia were used as an indicator of the psychological trait "negative affectivity." Previous studies have suggested that individuals with higher negative affectivity are more internally focused and, therefore, more likely to report somatic and visceral changes. During mild hypoglycemia, 42% of the sample subjects reported an increase in autonomic symptoms; 29% reported an increase in neuroglycopenic symptoms, and 28% estimated blood glucose levels accurately (within 10% of actual). Hormonal excursions did not predict any outcome, but higher anxiety levels during the euglycemic baseline were associated with better detection of hypoglycemic symptoms and more accurate estimation of blood glucose values after controlling for change in anxiety level during hypoglycemia. Psychological factors such as elevated anxiety levels ("negative affectivity") can influence blood glucose estimation and symptom detection in adolescents and young adults and may explain why some individuals are more adept than others at reducing their risk of severe hypoglycemia after participation in a formal blood glucose awareness training program.

Blood Glucose Discrimination Training: The Role of Internal and External Cues

The effects of observing internal and external events on blood glucose (BG) discrimination were assessed in eight patients with type 1 diabetes using an intrasubject design. During baseline condition, participants estimated their BG, then measured and recorded it (feedback-only procedure) three times a day. Participants were then divided randomly into two groups. Both were submitted to internal cue (IC) and external cue (EC) training conditions in a balanced order, and then both cues were presented together in combined cues (CC) training conditions. Under IC, participants observed and recorded their symptoms before estimating BG. Under EC, they observed and recorded environmental events prior to BG estimation. In CC conditions, participants paid attention to both internal and external cues before the estimate-feedback routine. BG estimation accuracy improved after either IC or EC conditions. When the two types of cues were combined, only two participants improved their BG estimation accuracy. The remainder did not, probably because they had already attained high accuracy levels (ceiling effect).

Diabetes teaching program improves glycemic control and preserves perception of hypoglycemia

Improvement of HbA 1c is frequently accompanied by deteriorating awareness of hypoglycemia. We studied the effect of improved metabolic control on hypoglycemia perception in 33 type 1 diabetic patients during 3 months after an inpatient diabetes education program of 5 days. Patients were grouped according to the presence (H, n=11) or the absence (N, n=22) of a history of repeated severe hypoglycemia. To measure awareness of blood glucose (BG) and hypoglycemia, we calculated their accuracy of BG perception (error grid analysis) and sensitivity for BG levels <3.9 mmol/l, respectively, during the first (I) and second (II) period of the 3 months using the method of BG estimation. HbA 1c decreased from 8.0±0.3% before to 7.1±0.2% 3 months after the program ( P<0.001) with no difference between H and N. Neither accuracy of BG perception (40.6±3.8 (I) versus 43.6±4.1% (II), P=0.25) nor sensitivity for low BG levels (49.1±4.2 (I) versus 54.9±4.9% (II), P=0.12) changed significantly. Group H had a lower overall accuracy of BG estimation ( P=0.048) and a lower overall sensitivity for detecting BG levels <3.9 mmol/l ( P=0.03) than group N. Group H was able to improve accuracy of BG estimation (H: 24.8±6.2 (I) versus 36.9±8.3% (II), P=0.04) while group N was not (48.5±3.9 (I) versus 46.9±4.6% (II), P=0.5). In conclusion, improvement of metabolic control after intensive diabetes education had no adverse effect on the perception of low BG levels. On the contrary, patients with a history of severe hypoglycemia improved their awareness of BG.

Symptom reporting in asthma patients and insulin-dependent diabetics

In this paper, results from two studies are presented. 1. (1) Sixty-eight diabetics registered their blood glucose levels both as estimated and as measured and they indicated the intensity of 20 symptoms on a symptom checklist. Data were assessed twice a day over a 30-day period. During this period, blood glucose levels decreased slightly, the accuracy of blood glucose estimation improved, and for about half of the subjects specific symptoms could be identified, which covaried closely with blood glucose levels over time. 2. (2) Fifty-three asthmatic patients monitored their peak flow each morning and evening over a period of 30 days. Before measuring peak flow, the patients estimated their peak flow and indicated the intensity of 28 symptoms specific for asthma. For about half of the sample, symptoms were identifiable, which correlated highly with measured peak flow. A substantial increase in the accuracy of estimated peak flow could be observed over time.

Accuracy of Blood Glucose Estimation by Children With IDDM and Their Parents

To evaluate the accuracy of blood glucose symptom recognition and subjective blood glucose estimation in insulin-dependent diabetic (IDDM) children and their parents. Blood glucose estimation questionnaires were completed 4 times/day at home during routine activities. A sequential sample of 19 families, who attended a pediatric diabetes clinic, with IDDM children less than 12 yr old and IDDM duration of greater than or equal to 9 mo comprised the study. Error grid analysis showed that both children and parents demonstrated poor accuracy, making clinically significant errors as frequently as clinically accurate estimates. The most common error was the failure to detect extreme blood glucose levels, with a significant tendency to underestimate hyperglycemia. Children often reported hypoglycemia when blood glucose was hyperglycemic. Confidence in the ability to estimate blood glucose was unrelated to measured accuracy. IDDM children and their parents demonstrated a higher rate of blood glucose estimation errors than IDDM adolescents and adults in previous studies. Even in families who use self-monitoring of blood glucose frequently, self-reported ability to recognize symptoms and estimate blood glucose should be viewed with caution. Families with IDDM children need more education about errors in symptom recognition and blood glucose estimation. They should also be encouraged to use self-monitoring of blood glucose before treating children's reported hypoglycemic symptoms whenever possible.

Intensive versus standard blood glucose awareness training (BGAT) with insulin-dependent diabetes: mechanisms and ancillary effects.

Insulin-dependent diabetes mellitus (IDDM) patients make critical daily self-care decisions on the basis of what they estimate their blood glucose (BG) levels to be. This study: a) replicated efficacy of Standard Blood Glucose Awareness Training (BGAT), b) evaluated the relative efficacy of an Intensive Blood Glucose Awareness Training (BGAT) to enhance patient accuracy of BG estimation, and c) evaluated the mechanisms and ancillary effects of BGAT. Thirty-nine subjects were randomly assigned to one of three groups. Compared with Control, both Standard and Intensive BGAT improved accuracy (p less than 0.001). Intensive BGAT post-treatment accuracy relative to Standard BGAT did not reach statistical significance (p = 0.177). Greater improvement in accuracy was associated with poorer pretreatment accuracy. Only Intensive BGAT improved metabolic control (glycosylated hemoglobin), and this improvement was associated with poorer pretreatment control. The effects of BGAT were highly specific, affecting only accuracy and metabolic control, and not affecting fear of hypoglycemia, diabetes knowledge, of frequency of blood glucose monitoring.

Enhancing Blood Glucose Awareness in Adolescents and Young Adults With IDDM

To determine the effectiveness of an intervention program designed to improve blood glucose awareness. Eight young-adult outpatients (mean age 22 yr) and six adolescent inpatients (mean age 14.5 yr) with insulin-dependent diabetes mellitus participated in the intervention program. Nine adolescent inpatients (mean age 13.9 yr) served as an untreated comparison group. One adult outpatient with unreliable data was removed. Before treatment, each patient completed a minimum of 40 blood glucose estimations, blood glucose tests, and symptom-rating checklists. Symptoms of hypo- or hyperglycemia were identified for each patient. The three-session intervention focused on internal (e.g., personal symptoms) and external (e.g., timing and amount of insulin, food, and exercise) cues that could be used to enhance blood glucose awareness. At postintervention, patients completed a minimum of 40 additional blood glucose estimates and tests. Comparison subjects completed the pre-postassessments but did not receive the intervention. Blood glucose estimation accuracy was evaluated with error grid analysis. All estimated-actual blood glucose values were plotted into one of five zones: accurate estimates (zone A), benign errors (zone B), and clinically dangerous errors (zones C, D, and E). An overall accuracy index (AI) was calculated by subtracting the summed percentage of clinically dangerous estimates (zones C, D, and E) from the percentage of accurate estimates (zone A). At study entry, the adolescent inpatients' mean AI of 7% was significantly poorer than the 32% mean AI exhibited by the outpatient young-adult sample (P less than 0.02). At postintervention, the adolescents' mean AI improved to 30% (P less than 0.02) and the young adults' mean outpatient AI improved to 45% (P less than 0.06). The treated sample as a whole exhibited increased sensitivity to both hypo- (P less than 0.005) and hyperglycemia (P less than 0.05). Similar improvements did not occur in the untreated comparison sample. Adolescents may exhibit poorer blood glucose awareness than adults. Although this intervention program improved blood glucose awareness in both adolescent and adult patients, postintervention blood glucose estimation accuracy remained far from ideal.

Subjective symptoms, blood glucose estimation, and blood glucose concentrations in adolescents with diabetes.

Twenty-five adolescent campers with insulin-dependent diabetes mellitus (IDDM) completed a Symptom Rating Checklist and estimated their blood glucose (BG) immediately before having their BG assessed four times daily for 11 days. Consistent relationships between BG and symptoms were not identified when the data were analyzed for the group as a whole. However, when each camper's data were analyzed separately, 23 of the 25 adolescents had at least one significant glycemia-symptom (G-S) correlation. Each camper seemed to have a unique G-S pattern; only one symptom (hungry) was significantly related to BG for more than half of the youngsters studied. Almost all of the significant G-S correlations were indicative of low rather than high BG. However, when asked, few campers were able to accurately identify which symptoms were reliably associated with low or high BG. In this study, different measures of BG estimation error led to different results. The percent of estimates +/- 20% of the actual BG value (55% in this study) was strongly influenced by the actual BG reading because higher BG values have larger accuracy ranges than lower BG concentrations. When estimated BG was simply subtracted from actual BG, under- and overestimates canceled each other out, resulting in an unusually small estimated error (5 mg/dl in this investigation). The absolute difference score ignores the direction of estimation error, but may more accurately reflect patients' average estimation error (68 mg/dl in this study). When actual and estimated BG values were correlated for the group as a whole, the patients appeared to be highly accurate at estimating BG (r = .93, P less than .0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood glucose discrimination training and metabolic control in insulin-dependent diabetics

Nine insulin-dependent diabetic adults were exposed to a blood glucose discrimination training program. Following baseline, during which Ss estimated their blood glucose levels twice daily, Ss received immediate feedback regarding the accuracy of their estimates. The procedure resulted in a large increase in accuracy of blood glucose estimation. Improvements in the ability to detect changes in blood glucose levels in the absence of chemical assessment, however, did not have a significant effect on long-term metabolic control. The implications of these findings are discussed.