Influence of simulated altitude on the performance of five blood glucose meters

People With Diabetes Using Insulin Flying Across Multiple Time Zones: Limitations and Opportunities for Diabetes Technologies

Increasingly, people with diabetes (PWD) are using wearable and other devices to support self-management. During air travel, there are 4 stakeholders involved in maximizing the safety of wireless devices for diabetes care used in flight: (1) manufacturers of the devices, (2) airlines, (3) the Transportation Security Administration, and (4) the U.S. Food and Drug Administration. These stakeholders have all developed technologies and policies that assist PWD who prepare for and take appropriate actions during long-haul flights. This article discusses the performance and use of 6 classes of specific wireless diabetes devices during an airplane flight, including the following: (1) blood glucose monitors, (2) continuous glucose monitors, (3) insulin pumps, (4) smart pens for dosing insulin injections, (5) advanced hybrid closed-loop systems, and (6) spinal cord stimulators for painful diabetic neuropathy. Through the policies and safeguards of the 4 stakeholders and the proper self-care measures that insulin-using PWD can take, it is possible to maintain safe glycemic levels on flights across multiple time zones.

UIAA Medical Commission Recommendations for Mountaineers, Hillwalkers, Trekkers, and Rock and Ice Climbers with Diabetes

Hillebrandt, David, Anil Gurtoo, Thomas Kupper, Paul Richards, Volker Schöffl, Pankaj Shah, Rianne van der Spek, Nikki Wallis, and Jim Milledge. UIAA Medical Commission recommendations for mountaineers, hillwalkers, trekkers, and rock and ice climbers with diabetes. High Alt Med Biol. 24: 110-126.-The object of this advice article is not only to give the diabetic mountaineer general guidance but also to inform his or her medical team of practical aspects of care that may not be standard for nonmountaineers. The guidelines are produced in seven sections. The first is an introduction to the guidelines, and the second is an introduction to this medical problem and is designed to be read and understood by diabetic patients and their companions. The third section is for use in an emergency in mountains. The fourth is for rock, ice, and competition climbers operating in a less remote environment. These initial sections are deliberately written in simple language. The fifth and sixth sections are written for clinicians and those with skills to read more technical information, and the seventh looks at modern technology and its pros and cons in diabetes management in a remote area. Sections One and Two could be laminated and carried when in the mountains, giving practical advice.

Wilderness Medical Society Clinical Practice Guidelines for Diabetes Management

The Wilderness Medical Society convened an expert panel in 2018 to develop a set of evidence-based guidelines for the treatment of type 1 and 2 diabetes, as well as the recognition, prevention, and treatment of complications of diabetes in wilderness athletes. We present a review of the classifications, pathophysiology, and evidence-based guidelines for planning and preventive measures, as well as best practice recommendations for both routine and urgent therapeutic management of diabetes and glycemic complications. These recommendations are graded based on the quality of supporting evidence and balance between the benefits and risks or burdens for each recommendation.

The Effects of High Altitude on Glucose Homeostasis, Metabolic Control, and Other Diabetes-Related Parameters: From Animal Studies to Real Life

Exposure to high altitude activates several complex and adaptive mechanisms aiming to protect human homeostasis from extreme environmental conditions, such as hypoxia and low temperatures. Short-term exposure is followed by transient hyperglycemia, mainly triggered by the activation of the sympathetic system, whereas long-term exposure results in lower plasma glucose concentrations, mediated by improved insulin sensitivity and augmented peripheral glucose disposal. An inverse relationship between altitude, diabetes, and obesity has been well documented. This is the result of genetic and physiological adaptations principally to hypoxia that favorably affect glucose metabolism; however, the contribution of financial, dietary, and other life-style parameters may also be important. According to existing evidence, people with diabetes are capable of undertaking demanding physical challenges even at extreme altitudes. Still, a number of issues should be taken into account, including the increased physical activity leading to changes in insulin demands and resistance, the performance of measurement systems under extreme weather conditions and the potential deterioration of metabolic control during climbing expeditions. The aim of this review is to present available evidence in the field in a comprehensive way, beginning from the physiology of glucose homeostasis adaptation mechanisms to high altitudes and ending to what real life experience has taught us.

Diabetes-Related Knowledge of Polish National Mountain Leaders

Nabrdalik, Katarzyna, Hanna Kwiendacz, Monika Gubała, Kinga Tyrała, Mariusz Seweryn, Andrzej Tomasik, Tomasz Sawczyn, Michał Kukla, Władysław Grzeszczak, and Janusz Gumprecht. Diabetes-related knowledge of Polish national mountain leaders. High Alt Med Biol. 19:237-243, 2018.-Mountain trekking is a popular activity for patients with diabetes. In Poland, mountain leaders often accompany organized groups to ensure their safety during treks; we aimed to evaluate their competency in caring for diabetic clients by assessing their diabetes-related knowledge. This was a cross-sectional study among Polish, certified, active mountain leaders carried out by means of an anonymous, standardized 41-item questionnaire adapted from a study by Wee et al. It was distributed through e-mail to 500 leaders. A total of 106 (21.2%) mountain leaders completed the questionnaire (males 60.4%) with a mean (standard deviation [SD]) age of 38.6 (13.5) years. Their mean (SD) length of experience acting as a mountain leader was 11.9 (10.2) years. The average score was 72.4% of the maximum possible (29.7 of 41 points). Results varied significantly depending on gender (p = 0.006). The percentage of correct answers among questions in each section varied between 23.6% and 100%. The main sources of diabetes-related knowledge identified by respondents were members of their family and their friends who suffer from diabetes (33%). First aid courses were indicated as sources of information by only 12.6% of the informants. Results of the questionnaire revealed that respondents did have a reasonable level of diabetes-related knowledge. There were topics in which the respondents achieved lower than an average score, demonstrating a need for further education.

MANAGEMENT OF DIABETES DURING AIR TRAVEL: A SYSTEMATIC LITERATURE REVIEW OF CURRENT RECOMMENDATIONS AND THEIR SUPPORTING EVIDENCE

OBJECTIVE

Individuals with diabetes are increasingly seeking pretravel advice, but updated professional recommendations remain scant. We performed a systematic review on diabetes management during air travel to summarize current recommendations, assess supporting evidence, and identify areas of future research.

METHODS

A systematic review of the English literature on diabetes management during air travel was undertaken utilizing PubMed and MEDLINE. Publications regarding general travel advice; adjustment of insulin and noninsulin therapies; and the use of insulin pumps, glucometers and subcutaneous glucose sensors at altitude were included. Gathered information was used to create an updated summary of glucose-lowering medication adjustment during air travel.

RESULTS

Sixty-one publications were identified, most providing expert opinion and few offering primary data (47 expert opinion, 2 observational studies, 2 case reports, 10 device studies). General travel advice was uniform, with increasing attention to preflight security. Indications for oral antihyperglycemic therapy adjustments varied. There were few recommendations on contemporary agents and on nonhypoglycemic adverse events. There was little consensus on insulin adjustment protocols, many antedating current insulin formulations. Most publications advocated adjusting insulin pump time settings after arrival; however, there was disagreement on timing and rate adjustments. Glucometers and subcutaneous glucose sensors were reported to be less accurate at altitude, but not to an extent that would preclude their clinical use.

CONCLUSION

Recommendations for diabetes management during air travel vary significantly and are mostly based on expert opinion. Data from systematic investigation on glucose-lowering medication adjustment protocols may support the development of a future consensus statement.

ABBREVIATIONS

CSII = continuous subcutaneous insulin infusion (device) DPP-4 = dipeptidyl peptidase 4 EGA = error grid analysis GDH = glucose dehydrogenase GOX = glucose oxidase GLP1 = glucagon-like peptide-1 NPH = neutral protamine Hagedorn SGLT2 = sodium-glucose cotransporter-2.

Interferences and Limitations in Blood Glucose Self-Testing: An Overview of the Current Knowledge

In general, patients with diabetes performing self-monitoring of blood glucose (SMBG) can strongly rely on the accuracy of measurement results. However, various factors such as application errors, extreme environmental conditions, extreme hematocrit values, or medication interferences may potentially falsify blood glucose readings. Incorrect blood glucose readings may lead to treatment errors, for example, incorrect insulin dosing. Therefore, the diabetes team as well as the patients should be well informed about limitations in blood glucose testing. The aim of this publication is to review the current knowledge on limitations and interferences in blood glucose testing with the perspective of their clinical relevance.

Use of capillary blood glucose for screening for gestational diabetes mellitus in resource-constrained settings

AIMS

The aim of the study was to evaluate usefulness of capillary blood glucose (CBG) for diagnosis of gestational diabetes mellitus (GDM) in resource-constrained settings where venous plasma glucose (VPG) estimations may be impossible.

METHODS

Consecutive pregnant women (n = 1031) attending antenatal clinics in southern India underwent 75-g oral glucose tolerance test (OGTT). Fasting, 1- and 2-h VPG (AU2700 Beckman, Fullerton, CA) and CBG (One Touch Ultra-II, LifeScan) were simultaneously measured. Sensitivity and specificity were estimated for different CBG cut points using the International Association of Diabetes in Pregnancy Study Groups (IADPSG) criteria for the diagnosis of GDM as gold standard. Bland-Altman plots were drawn to look at the agreement between CBG and VPG. Correlation and regression equation analysis were also derived for CBG values.

RESULTS

Pearson's correlation between VPG and CBG for fasting was r = 0.433 [intraclass correlation coefficient (ICC) = 0.596, p < 0.001], for 1H, it was r = 0.653 (ICC = 0.776, p < 0.001), and for 2H, r = 0.784 (ICC = 0.834, p < 0.001). Comparing a single CBG 2-h cut point of 140 mg/dl (7.8 mmol/l) with the IADPSG criteria, the sensitivity and specificity were 62.3 and 80.7 %, respectively. If CBG cut points of 120 mg/dl (6.6 mmol/l) or 110 mg/dl (6.1 mmol/l) were used, the sensitivity improves to 78.3 and 92.5 %, respectively.

CONCLUSIONS

In settings where VPG estimations are not possible, CBG can be used as an initial screening test for GDM, using lower 2H CBG cut points to maximize the sensitivity. Those who screen positive can be referred to higher centers for definitive testing, using VPG.

Glucose homeostasis during short-term and prolonged exposure to high altitudes

Most of the literature related to high altitude medicine is devoted to the short-term effects of high-altitude exposure on human physiology. However, long-term effects of living at high altitudes may be more important in relation to human disease because more than 400 million people worldwide reside above 1500 m. Interestingly, individuals living at higher altitudes have a lower fasting glycemia and better glucose tolerance compared with those who live near sea level. There is also emerging evidence of the lower prevalence of both obesity and diabetes at higher altitudes. The mechanisms underlying improved glucose control at higher altitudes remain unclear. In this review, we present the most current evidence about glucose homeostasis in residents living above 1500 m and discuss possible mechanisms that could explain the lower fasting glycemia and lower prevalence of obesity and diabetes in this population. Understanding the mechanisms that regulate and maintain the lower fasting glycemia in individuals who live at higher altitudes could lead to new therapeutics for impaired glucose homeostasis.

Study of the effect of altitude on the measurement of glycated haemoglobin using point-of-care instruments

We measured the glycated haemoglobin (HbA1c) levels of a total of 24 non-diabetic volunteers and diabetic patients using a point-of-care (POC) analyser in three Cameroonian cities at different altitudes. Although 12 to 25% of duplicates had more than 0.5% (8 mmol/mol) difference across the sites, HbA1c values correlated significantly (r = 0.89-0.96). Further calibration studies against gold-standard measures are warranted.

System accuracy of blood glucose monitoring systems: impact of use by patients and ambient conditions

For self-monitoring of blood glucose by people with diabetes, the reliability of the measured blood glucose values is a prerequisite in order to ensure correct therapeutic decisions. Requirements for system accuracy are defined by the International Organization for Standardization (ISO) in the standard EN ISO 15197:2003. However, even a system with high analytical quality is not a guarantee for accurate and reliable measurement results. Under routine life conditions, blood glucose measurement results are affected by several factors. First, the act of performing measurements as well as the handling of the system may entail numerous possible error sources, such as traces of glucose-containing products on the fingertips, the use of deteriorated test strips, or the incorrect storage of test strips. Second, ambient and sampling conditions such as high altitude, partial pressure of oxygen, ambient temperature, and the use of alternate test sites can have an influence on measurement results. Therefore, the user-friendliness of a system and the quality of the manufacturer's labeling to reduce the risk of handling errors are also important aspects in ensuring reliable and accurate measurement results. In addition, the analytical performance of systems should be less prone to user errors and ambient conditions. Finally, people with diabetes must be aware of the information and instructions in the manufacturer's labeling and must be able to measure and interpret blood glucose results correctly.

Effects of simulated altitude on blood glucose meter performance: implications for in-flight blood glucose monitoring

BACKGROUND

Most manufacturers of blood glucose monitoring equipment do not give advice regarding the use of their meters and strips onboard aircraft, and some airlines have blood glucose testing equipment in the aircraft cabin medical bag. Previous studies using older blood glucose meters (BGMs) have shown conflicting results on the performance of both glucose oxidase (GOX)- and glucose dehydrogenase (GDH)-based meters at high altitude. The aim of our study was to evaluate the performance of four new-generation BGMs at sea level and at a simulated altitude equivalent to that used in the cabin of commercial aircrafts.

METHODOLOGY/PRINCIPAL FINDINGS

Blood glucose measurements obtained by two GDH and two GOX BGMs at sea level and simulated altitude of 8000 feet in a hypobaric chamber were compared with measurements obtained using a YSI 2300 blood glucose analyzer as a reference method. Spiked venous blood samples of three different glucose levels were used. The accuracy of each meter was determined by calculating percentage error of each meter compared with the YSI reference and was also assessed against standard International Organization for Standardization (ISO) criteria. Clinical accuracy was evaluated using the consensus error grid method. The percentage (standard deviation) error for GDH meters at sea level and altitude was 13.36% (8.83%; for meter 1) and 12.97% (8.03%; for meter 2) with p = .784, and for GOX meters was 5.88% (7.35%; for meter 3) and 7.38% (6.20%; for meter 4) with p = .187. There was variation in the number of time individual meters met the standard ISO criteria ranging from 72-100%. Results from all four meters at both sea level and simulated altitude fell within zones A and B of the consensus error grid, using YSI as the reference.

CONCLUSIONS

Overall, at simulated altitude, no differences were observed between the performance of GDH and GOX meters. Overestimation of blood glucose concentration was seen among individual meters evaluated, but none of the results obtained would have resulted in dangerous failure to detect and treat blood glucose errors or in giving treatment that was actually contradictory to that required.

Continuous glucose monitoring--a study of the Enlite sensor during hypo- and hyperbaric conditions

BACKGROUND

The performance and accuracy of the Enlite(™) (Medtronic, Inc., Northridge, CA) sensor may be affected by microbubble formation at the electrode surface during hypo- and hyperbaric conditions. The effects of acute pressure changes and of prewetting of sensors were investigated.

MATERIALS AND METHODS

On Day 1, 24 sensors were inserted on the right side of the abdomen and back in one healthy individual; 12 were prewetted with saline solution, and 12 were inserted dry. On Day 2, this procedure was repeated on the left side. All sensors were attached to an iPro continuous glucose monitoring (CGM) recorder. Hypobaric and hyperbaric tests were conducted in a pressure chamber, with each test lasting 105 min. Plasma glucose values were obtained at 5-min intervals with a HemoCue(®) (Ängelholm, Sweden) model 201 glucose analyzer for comparison with sensor glucose values.

RESULTS

Ninety percent of the CGM systems operated during the tests. The mean absolute relative difference was lower during hyperbaric than hypobaric conditions (6.7% vs. 14.9%, P<0.001). Sensor sensitivity was slightly decreased (P<0.05) during hypobaric but not during hyperbaric conditions. Clarke Error Grid Analysis showed that 100% of the values were found in the A+B region. No differences were found between prewetted and dry sensors.

CONCLUSIONS

The Enlite sensor performed adequately during acute pressure changes and was more accurate during hyperbaric than hypobaric conditions. Prewetting the sensors did not improve accuracy. Further studies on type 1 diabetes subjects are needed under various pressure conditions.

Comparison of capillary whole blood versus venous plasma glucose estimations in screening for diabetes mellitus in epidemiological studies in developing countries

BACKGROUND

This study compared capillary blood glucose (CBG) measurements with venous plasma glucose (VPG) measurements in screening for diabetes and prediabetes in epidemiological studies.

METHODS

Four hundred seven subjects ≥ 20 years old (54.1% male) without previously known diabetes underwent oral glucose tolerance tests at a tertiary diabetes center in Chennai, India. Simultaneous measurements of CBG (OneTouch(®) Ultra(®) meter, LifeScan, a Johnson & Johnson Company, Milpitas, CA) and VPG (AU2700, Beckman, Fullerton, CA) were performed, both in the fasting state and 2 h after a 75-g glucose load (2-h post-glucose [PG]). Diabetes, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) were defined using American Diabetes Association (ADA) and World Health Organization (WHO) criteria.

RESULTS

The mean fasting CBG and VPG values were 122 ± 39 mg/dL and 115 ± 40 mg/dL, respectively, and the 2-h PG values were 203 ± 84 mg/dL and 176 ± 85 mg/dL, respectively. The Pearson's correlation coefficient for CBG with VPG was 0.681 (P < 0.001) in the fasting state and 0.897 (P < 0.001) for the 2-h PG load, indicating good correlation between the two methods. Based on the ADA fasting criteria, 31.9% versus 21.1% (capillary vs. venous) had diabetes, whereas based on the WHO criteria, 43.2% versus 38.6% (capillary vs. venous) had diabetes. The accuracy of identifying diabetes was 83.3% by the ADA and 90.9% by WHO criteria, for IGT it was 85.3%, and for IFG it was 66.3% by the ADA and 72.2% by the WHO criteria.

CONCLUSION

CBG is a feasible alternative for screening of diabetes and IGT in epidemiological studies in developing countries where obtaining venous samples may be difficult.

Accuracy of handheld blood glucose meters at high altitude

Background

Due to increasing numbers of people with diabetes taking part in extreme sports (e.g., high-altitude trekking), reliable handheld blood glucose meters (BGMs) are necessary. Accurate blood glucose measurement under extreme conditions is paramount for safe recreation at altitude. Prior studies reported bias in blood glucose measurements using different BGMs at high altitude. We hypothesized that glucose-oxidase based BGMs are more influenced by the lower atmospheric oxygen pressure at altitude than glucose dehydrogenase based BGMs.

Methodology/Principal Findings

Glucose measurements at simulated altitude of nine BGMs (six glucose dehydrogenase and three glucose oxidase BGMs) were compared to glucose measurement on a similar BGM at sea level and to a laboratory glucose reference method. Venous blood samples of four different glucose levels were used. Moreover, two glucose oxidase and two glucose dehydrogenase based BGMs were evaluated at different altitudes on Mount Kilimanjaro. Accuracy criteria were set at a bias <15% from reference glucose (when >6.5 mmol/L) and <1 mmol/L from reference glucose (when <6.5 mmol/L). No significant difference was observed between measurements at simulated altitude and sea level for either glucose oxidase based BGMs or glucose dehydrogenase based BGMs as a group phenomenon. Two GDH based BGMs did not meet set performance criteria. Most BGMs are generally overestimating true glucose concentration at high altitude.

Conclusion

At simulated high altitude all tested BGMs, including glucose oxidase based BGMs, did not show influence of low atmospheric oxygen pressure. All BGMs, except for two GDH based BGMs, performed within predefined criteria. At true high altitude one GDH based BGM had best precision and accuracy.

Performance of glucose dehydrogenase (GDH) based and glucose oxidase (GOX) based blood glucose meter systems at moderately high altitude

OBJECTIVE

Self-monitoring of blood glucose (SMBG) is a fairly efficient method of preventing hypoglycaemia in diabetic patients. Blood glucose meters (BGMs) are influenced by factors such as altitude, temperature, blood oxygen concentration, low atmospheric pressure or humidity. In this study we aimed at evaluating the performance of glucose dehydrogenase (GDH) or glucose oxidase (GOX) based glucometers at moderately high altitude.

METHOD

A total of 286 female or male patients, most of whom had type 2 diabetes, were included in this study. The simultaneous readings made by two different glucometers were compared with the readings made at the reference laboratory.

RESULTS

Blood glucose levels measured by a GDH based glucometer at moderately high altitude were significantly (p=0.007) higher compared to those measured at the reference laboratory. Although blood glucose levels measured by a GOX based glucometer were lower compared to those measured at the reference laboratory, the difference was not significant (p=0.54). The difference between GOX and GDH readings with regard to blood glucose levels was also significant (p=0.001). Blood glucometers were influenced by moderately high altitude.

CONCLUSION

The use of a GOX based glucometer at moderately high altitude may be useful in detecting hypoglycaemia at these conditions, since significantly higher blood glucose levels were measured with a GDH based glucometer compared to reference readings.

Residents at high altitude show a lower glucose profile than sea-level residents throughout 12-hour blood continuous monitoring

It is known that residents at high altitude (HA) have a lower basal glycemia than residents at sea level (SL). However, whether such a difference is maintained throughout the full day remains unknown. We compared 12-h blood glucose profiles from 10 healthy males native residents at HA (3250 m) and 8 male residents at SL. Glucose profile at HA was lower throughout the glucose monitoring than that at SL (mean profile: 50.6 +/- 3.7 and 73.4 +/- 4.0 mg/dL, respectively; p < 0.001). Basal and postprandial insulin and triacylglycerol values were similar in both groups. In conclusion, HA natives resident have a lower blood glucose profile than SL residents throughout 12-h continuous monitoring.

Going High with Type 1 Diabetes

This review aims to identify the main issues facing a healthy and well-controlled type-1 diabetic mountaineer at high altitude. Most of the problems are self-managed by the diabetic climber although the risk of serious morbidity or even death remains. Given the scarce evidence on diabetes at altitude, an extensive search of the literature, including case reports and anecdotes was carried out to reach the recommendations.

Effect of high altitude on blood glucose meter performance

Participation in high-altitude wilderness activities may expose persons to extreme environmental conditions, and for those with diabetes mellitus, euglycemia is important to ensure safe travel. We conducted a field assessment of the precision and accuracy of seven commonly used blood glucose meters while mountaineering on Mount Rainier, located in Washington State (elevation 14,410 ft). At various elevations each climber-subject used the randomly assigned device to measure the glucose level of capillary blood and three different concentrations of standardized control solutions, and a venous sample was also collected for later glucose analysis. Ordinary least squares regression was used to assess the effect of elevation and of other environmental potential covariates on the precision and accuracy of blood glucose meters. Elevation affects glucometer precision (p = 0.08), but becomes less significant (p = 0.21) when adjusted for temperature and relative humidity. The overall effect of elevation was to underestimate glucose levels by approximately 1-2% (unadjusted) for each 1,000 ft gain in elevation. Blood glucose meter accuracy was affected by elevation (p = 0.03), temperature (p < 0.01), and relative humidity (p = 0.04) after adjustment for the other variables. The interaction between elevation and relative humidity had a meaningful but not statistically significant effect on accuracy (p = 0.07). Thus, elevation, temperature, and relative humidity affect blood glucose meter performance, and elevated glucose levels are more greatly underestimated at higher elevations. Further research will help to identify which blood glucose meters are best suited for specific environments.

Extreme altitude mountaineering and Type 1 diabetes; the Diabetes Federation of Ireland Kilimanjaro Expedition

AIMS

To examine the effects of extreme altitude mountaineering on glycaemic control in Type 1 diabetes, and to establish whether diabetes predisposes to acute mountain sickness (AMS).

METHODS

Fifteen people with Type 1 diabetes and 22 nondiabetic controls were studied during the Diabetes Federation of Ireland Expedition to Kilimanjaro. Daily insulin requirements, blood glucose estimations and hypoglycaemic attacks were recorded in diaries by the people with diabetes. The performance of blood glucose meters at altitude was assessed using standard glucose solutions. Symptoms of acute mountain sickness were recorded daily by people with diabetes and by the nondiabetic controls using the Lake Louise Scoring Charts. The expedition medical team recorded the incidence of complications of altitude and of diabetes. The final height attained for each individual was recorded by the expedition medical team and verified by the expedition guides.

RESULTS

The final altitude ascended was lower in the diabetic than the nondiabetic group (5187 +/- 514 vs. 5654 +/- 307 m, P = 0.001). The mean daily insulin dose was reduced from 67.1 +/- 28.3-32.9 +/- 11.8 units (P < 0.001), but only 50% of recorded blood glucose readings were within the target range of 6-14 mmol/L. There were few hypoglycaemic attacks after the first two days of climbing. Both blood glucose meters tested showed readings as low as 60% of standard glucose concentrations at high altitude and low temperatures. The Lake Louise questionnaires showed that symptoms of AMS occurred equally in the diabetic and nondiabetic groups. There were two episodes of mild diabetic ketoacidosis; two of the diabetic group and three of the nondiabetic group developed retinal haemorrhages.

CONCLUSIONS

People with Type 1 diabetes can participate in extreme altitude mountaineering. However, there are significant risks associated with this activity, including hypoglycaemia, ketoacidosis and retinal haemorrhage, with the additional difficulties in assessing glycaemic control due to meter inaccuracy at high altitude. People with Type 1 diabetes must be carefully counselled before attempting extreme altitude mountaineering.

Assessment of five portable blood glucose meters, a point-of-care analyzer, and color test strips for measuring blood glucose concentration in dogs

OBJECTIVE

To compare blood glucose concentrations obtained using a point-of-care (POC) analyzer, 5 portable blood glucose meters (PBGM), and a color reagent test strip with concentrations obtained using a reference method, and to compare glucose concentrations obtained using fresh blood samples in the PBGM with concentrations obtained using blood anticoagulated with lithium heparin.

DESIGN

Case series.

SAMPLE POPULATION

110 blood samples from 34 dogs; glucose concentration of the samples ranged from 41 to 596 mg/dl.

PROCEDURE

Logistic regression was used to compare blood glucose concentrations obtained with the various devices with reference method concentrations. Ease of use was evaluated subjectively. Percentage of times a clinical decision would have been altered if results of each of these methods had been used, rather than results of the reference method, was calculated.

RESULTS

For 3 of the PBGM, blood glucose concentrations obtained with fresh blood were not significantly different from concentrations obtained with blood samples anticoagulated with lithium heparin. None of the devices provided results statistically equivalent to results of the reference method, but the POC analyzer was more accurate than the others. For some samples, reliance on results of the PBGM or the color test strip would have resulted in erroneous clinical decisions.

CONCLUSIONS AND CLINICAL RELEVANCE

Although commercially available PBGM and color test strips provided blood glucose concentrations reasonably close to those obtained with reference methods, some devices were more accurate than others. Use of results from these devices could lead to erroneous clinical decisions in some cases.

Important features of blood glucose meters

OBJECTIVE

To provide an overview of several blood glucose meters that will enhance practicing pharmacists' knowledge and understanding of these devices to allow education of the patient with diabetes.

DATA SOURCES

Original and review articles, blood glucose meter package inserts and manuals.

DATA SYNTHESIS

Careful blood glucose control is essential to prevent long-term complications of diabetes. Newer blood glucose meters have a broad variety of features, including small size, extended memory capacity, blood glucose manipulation techniques, and computer downloading capabilities. The decision to choose a blood glucose meter should be based on a number of criteria, including the patient's needs, ease of use, and affordability.

CONCLUSION

Pharmacists must position themselves to differentiate among the numerous blood glucose meters available on the market and make appropriate recommendations based on patient-specific needs.