Clinical inertia.

Medicine has traditionally focused on relieving patient symptoms. However, in developed countries, maintaining good health increasingly involves management of such problems as hypertension, dyslipidemia, and diabetes, which often have no symptoms. Moreover, abnormal blood pressure, lipid, and glucose values are generally sufficient to warrant treatment without further diagnostic maneuvers. Limitations in managing such problems are often due to clinical inertia-failure of health care providers to initiate or intensify therapy when indicated. Clinical inertia is due to at least three problems: overestimation of care provided; use of "soft" reasons to avoid intensification of therapy; and lack of education, training, and practice organization aimed at achieving therapeutic goals. Strategies to overcome clinical inertia must focus on medical students, residents, and practicing physicians. Revised education programs should lead to assimilation of three concepts: the benefits of treating to therapeutic targets, the practical complexity of treating to target for different disorders, and the need to structure routine practice to facilitate effective management of disorders for which resolution of patient symptoms is not sufficient to guide care. Physicians will need to build into their practice a system of reminders and performance feedback to ensure necessary care.

Hypoglycemia in patients with type 2 diabetes mellitus.

BACKGROUND: Although hypoglycemia is the most common complication of intensive diabetes therapy, there is little information about risk factors for hypoglycemia in patients with type 2 diabetes mellitus. OBJECTIVE: To determine the prevalence and predisposing factors for hypoglycemia in patients with type 2 diabetes. METHODS: Retrospective, cross-sectional analysis set in an outpatient specialty diabetes clinic. We included those patients who had baseline and follow-up visits from April 1 through October 31, 1999. Hypoglycemia was defined as typical symptoms relieved by eating, and/or blood glucose level of less than 60 mg/dL (<3.3 mmol/L). Univariate and multivariate logistic regression were used to determine the contributions to hypoglycemia of age, sex, diabetes duration, body mass index (calculated as weight in kilograms divided by the square of height in meters), fasting plasma glucose level, glycosylated hemoglobin (HbA(1c)) level, type of therapy, and previous episodes at the follow-up visit. RESULTS: We studied 1055 patients. Prevalence of hypoglycemic symptoms was 12% (9/76) for patients treated with diet alone, 16% (56/346) for those using oral agents alone, and 30% (193/633) for those using any insulin (P<.001). Severe hypoglycemia occurred in only 5 patients (0.5%), all using insulin. Multiple logistic regression analysis demonstrated that insulin therapy, lower HbA(1c) level at follow-up, younger age, and report of hypoglycemia at the baseline visit were independently associated with increased prevalence of hypoglycemia. There were no significant predictors of severe hypoglycemia. CONCLUSIONS: Mild hypoglycemia is common in patients with type 2 diabetes undergoing aggressive diabetes management, but severe hypoglycemia is rare. Concerns about hypoglycemia should not deter efforts to achieve tight glycemic control in most patients with type 2 diabetes.

Comorbidity and glycemic control in patients with type 2 diabetes.

BACKGROUND: It is commonly believed that good glycemic control is hard to achieve in patients with diabetes mellitus and concurrent chronic illnesses. OBJECTIVE: To determine the impact of comorbidity on glycemic control at presentation and subsequent follow-up in patients with type 2 diabetes. METHODS: We studied 654 consecutive patients who presented to a diabetes clinic in 1997. Comorbidity was rated using the Chronic Disease Score (CDS) index, which is a validated, weighted score that takes into account the patient's age, sex, and classes of medications. Univariate and multivariate linear regressions were used to determine the contribution of age, body mass index (calculated as weight in kilograms divided by the square of height in meters), diabetes duration, type of therapy, and CDS to initial hemoglobin A(1c) (HbA(1c)) level. A similar analysis was performed for the 169 patients with follow-up HbA(1c) levels 6 months after presentation. RESULTS: Patients were 90% African American, and 66% female, with average age of 53 years. Average diabetes duration was 5 years; body mass index, 33; HbA(1c) level, 8.8%; and CDS, 1121 (range, 232-7953). At presentation, patients with higher CDSs tended to be older and to have a lower HbA(1c) level, but multivariate linear regression showed that receiving pharmacological therapy, younger age, and having a lower C-peptide level were the only significant contributors to HbA(1c) level. In the 169 follow-up patients, presenting characteristics were not significantly different from those of the full cohort: average initial HbA(1c) level was 8.8%; CDS, 1073. Their HbA(1c) level at 6 months averaged 7.5% and the CDS had no significant impact on their follow-up HbA(1c) level. CONCLUSION: Comorbidity does not appear to limit achievement of good glycemic control in patients with type 2 diabetes.

The influence of "host release factor" on carbon release by zooxanthellae isolated from fed and starved Aiptasia pallida (Verrill).

Symbiotic dinoflagellates (zooxanthellae) typically respond to extracts of host tissue with enhanced release of short-term photosynthetic products. We examined this "host release factor" (HRF) response using freshly isolated zooxanthellae of differing nutritional status. The nutritional status was manipulated by either feeding or starving the sea anemone Aiptasia pallida (Verrill). The release of fixed carbon from isolated zooxanthellae was measured using 14C in 30 min experiments. Zooxanthellae in filtered seawater alone released approximately 5% of photosynthate irrespective of host feeding history. When we used a 10-kDa ultrafiltrate of A. pallida host tissue as a source of HRF, approximately 14% of photosynthate was released to the medium. This increased to over 25% for zooxanthellae from anemones starved for 29 days or more. The cell-specific photosynthetic rate declined with starvation in these filtrate experiments, but the decline was offset by the increased percentage release. Indeed, the total amount of released photosynthate remained unchanged, or even increased, as zooxanthellae became more nutrient deficient. Similar trends were also observed when zooxanthellae from A. pallida were incubated in a 3-kDa ultrafiltrate of the coral Montastraea annularis, suggesting that HRF in the different filtrates operated in a similar manner. Our results support the suggestion that HRF diverts surplus carbon away from storage compounds to translocated compounds such as glycerol.

The potentially poor response to outpatient diabetes care in urban African-Americans.

OBJECTIVE: HbA1c levels can be reduced in populations of diabetic patients, but some individuals may exhibit little improvement. To search for reasons underlying differences in HbA1c outcome, we analyzed patients managed in an outpatient diabetes clinic. RESEARCH DESIGN AND METHODS: African-Americans with type 2 diabetes were categorized as responders, intermediate responders or poor responders according to their HbA1c level after 1 year of care. Logistical regression was used to determine baseline characteristics that distinguished poor responders from responders. Therapeutic strategies were examined for each of the response categories. RESULTS: The 447 patients had a mean age and disease duration of 58 and 5 years, respectively, and BMI of 32 kg/m2. Overall, the mean HbA1c level fell from 9.6 to 8.1% after 12 months. Mean HbA1c levels improved from 8.8 to 6.2% in responders, and from 9.5 to 7.9% in intermediate responders. In poor responders, the average HbA1c level was 10.8% on presentation and 10.9% at 1 year. The odds of being a poor responder were significantly increased with longer disease duration, higher initial HbA1c level, and greater BMI. Although doses of oral agents and insulin were significantly higher among poor responders at most visits, the acceleration of insulin therapy did not occur until late in the follow-up period. CONCLUSIONS: Clinical diabetes programs need to devise methods to identify patients who are at risk for persistent hyperglycemia. Whereas patient characteristics explain some heterogeneity of HbA1c outcome (and may aid in earlier identification of patients who potentially may not respond to conventional treatment), insufficient intensification of therapy may also be a component underlying the failure to achieve glycemic goals.

Physician assistant students and diabetes: evaluation of attitudes and beliefs.

PURPOSE: Physician assistants are assuming a greater role in patient care in the US health system. The objective of this study was to examine attitudes and beliefs about diabetes among physician assistant trainees. METHODS: A survey of 3 currently enrolled classes of physician assistant students was conducted using the Diabetes Attitude Survey (DAS, version 3). An additional question was presented to gather information about the level of hyperglycemia at which students would intensify diabetes therapy. RESULTS: On average, students scored high on all subscales, indicating general agreement with the attitudes examined by the DAS. For 3 subscales (seriousness of type 2 diabetes, value of tight glucose control, and patient autonomy), significant differences were seen across year of training. When asked about the level of glucose control at which they would advance therapy, a wide range of responses occurred, with some being out of target. CONCLUSIONS: Physician assistant students had favorable attitudes regarding type 2 diabetes. However, deficits appear to exist in understanding when to advance therapy. More studies on physician assistant students' knowledge of diabetes standards of care are required.

Diabetes in urban African-Americans. XIX. Prediction of the need for pharmacological therapy.

OBJECTIVE: To develop a prediction rule that will identify patients who will require pharmacological therapy within 6 months of first presentation to a diabetes clinic. RESEARCH DESIGN AND METHODS: Among the patients who came to the Grady Diabetes Clinic between 1991 and 1997, we randomized 557 frequent attenders to a development group and 520 frequent attenders to a validation group. Using multiple logistical regression, we derived a prediction rule in the development group to project whether patients would require pharmacological intervention to achieve HbA1c levels <7% after 6 months. The utility of the prediction rule was then confirmed in the validation group and tested prospectively on an additional group of 93 patients who presented from 1997 to 1998. Performance of the prediction rule was assessed using receiver operating characteristic (ROC) curves. RESULTS: The rule (-4.469 + 1.932 x sulfonylurea Rx + 1.334 x insulin Rx + 0.196 x duration + 0.468 x fasting glucose, where "Rx" indicates a prescription) predicted the need for pharmacological intervention in the development group (P < 0.0001). Use of insulin or sulfonylurea therapy at presentation, duration of diabetes, and fasting glucose levels were significant predictors of the future need for pharmacological management. The prediction rule also performed well in the validation group (positive predictive value 90%, correlation between predicted and observed need for medical management 0.99). ROC curves confirmed the value of the prediction rule (area under the curves was 0.91 for the development group, 0.85 for the validation group, and 0.81 for the prospective group). CONCLUSIONS: Early identification of individuals who will require pharmacological intervention to achieve national standards for glycemic control can be achieved with high probability, thus allowing for more efficient management of diabetes.

The pattern of dyslipidemia among urban African-Americans with type 2 diabetes.

OBJECTIVE: To analyze lipid profiles from a large sample of African-American patients with type 2 diabetes who receive care at an urban outpatient diabetes clinic. RESEARCH DESIGN AND METHODS: Fasting serum lipid profiles of 4,014 African-Americans and 328 Caucasians with type 2 diabetes were retrieved from a computerized registry. American Diabetes Association criteria were applied to classify LDL cholesterol, HDL cholesterol, and triglyceride (TG) levels into risk categories. The proportion of patients who had none, one, two, and three lipoprotein concentrations outside of recommended clinical targets was examined. Multiple logistical regression analyses were performed to determine the influence of sex and race on the probability of having a lipid level outside of the recommended target. RESULTS: The percentages of African-Americans with high-, borderline-, and low-risk LDL cholesterol concentrations were 58, 26, and 16%, respectively, and the percentages for Caucasians were 54, 29, and 16%, respectively (P = 0.51). For HDL cholesterol, 41, 33, and 26% of African-Americans were in the high-, borderline-, and low-risk categories, respectively, compared with 73, 18, and 9% of Caucasians, respectively (P < 0.0001). Nearly 81% of African-Americans had TG concentrations that were in the low-risk category compared with only 50% of Caucasians. More women than men had high-risk LDL and HDL cholesterol profiles. The most common pattern of dyslipidemia was an LDL cholesterol level above target combined with an HDL cholesterol level below target, which was detected in nearly 50% of African-Americans and 42% of Caucasians. African-Americans had lower odds of having an HDL cholesterol or TG level outside of target. African-American women, compared to men, had greater probabilities of having abnormal levels of LDL and HDL, but a lower likelihood of having a TG level above goal. CONCLUSIONS: In a large sample of urban type 2 diabetic patients receiving care at a diabetes treatment program, race and sex differences in serum lipid profiles were present. Because hypertriglyceridemia was rare among African-American subjects, interventions will need to focus primarily on improving their LDL and HDL cholesterol levels. Further studies are required regarding how to best adapt these observed differences into more effective strategies to optimize lipid levels for this population of diabetic patients and to determine whether similar patterns of dyslipidemia occur in other clinical settings.

Electronic journals: are they a paradigm shift?

Ejournals are becoming an accepted and necessary means of meeting the demands for the dissemination of knowledge. This introductory article discusses the recent "explosion" of ejournals and provides an explanation of what is meant by an "ejournal." Ejournals are explored within the traditional context of scholarship and a discussion of the "serials crisis" that promoted the inception of ejournals is presented. After laying the groundwork for discussing scholarship in this new age of dissemination of scholarly information, the article discusses whether this digital form of publication can be called a "paradigm shift" in Kuhn's (1970) traditional sense of the word.

Diabetes in urban African-Americans. XVII. Availability of rapid HbA1c measurements enhances clinical decision-making.

OBJECTIVE: To assess the impact of rapid-turnaround HbA1c results on providers' clinical decision-making and on follow-up HbA1c levels. RESEARCH DESIGN AND METHODS: The research design was a randomized clinical trial in which rapid HbA1c results were made available to providers on even days of the month (rapid, n = 575), but delayed by 24 h on odd days (conventional, n = 563). Adjustment of therapy for patients with type 2 diabetes was considered appropriate if therapy was intensified for HbA1c values >7% or not intensified for HbA1c values < or =7%. A post-hoc analysis was also performed using patients (n = 574) who returned for follow-up 2-7 months later to ascertain the effect of rapid HbA1c availability on subsequent glycemic control. RESULTS: Rapid HbA1c availability resulted in more appropriate management compared with conventional HbA1c availability (79 vs. 71%, P = 0.003). This difference was due mainly to less frequent intensification when HbA1c levels were < or =7% (10 vs. 22%, P < 0.0001) and slightly to more frequent intensification for patients with HbA1c values >7% (67 vs. 63%, P = 0.33). For both groups, intensification was greatest for patients on insulin (51%) compared with patients on oral agents (35%) and diet alone (14%) (P < 0.0001). Regression analysis confirmed that providers receiving conventional HbA1c results were more likely to intensify therapy in patients who already had HbA1c levels < or =7%. Over 2-7 months of follow-up, HbA1c rose more in patients with conventional HbA1c results compared with rapid results (0.8 vs. 0.4%, P = 0.02). In patients with initial HbA1c >7%, rapid HbA1c results had a favorable impact on follow-up HbA1c independent of the decision to intensify therapy (P = 0.03). CONCLUSIONS: Availability of rapid HbA1c determinations appears to facilitate diabetes management. The more favorable follow-up HbA1c profile in the rapid HbA1c group occurs independently of the decision to intensify therapy, suggesting the involvement of other factors such as enhanced provider and/or patient motivation.

Diabetes in urban African-Americans. XVI. Overcoming clinical inertia improves glycemic control in patients with type 2 diabetes.

OBJECTIVE: Diabetes care can be limited by clinical inertia-failure of the provider to intensify therapy when glucose levels are high. Although disease management programs have been proposed as a means to improve diabetes care, there are few studies examining their effectiveness in patient populations that have traditionally been underserved. We examined the impact of our management program in the Grady Diabetes Unit, which provides care primarily to urban African-American patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: We assessed glycemic outcomes in patients with type 2 diabetes who had an intake evaluation between 1992 and 1996 and who were identified on the basis of compliance with keeping the recommended number of return visits. For 698 patients, we analyzed changes in HbA1c values between baseline and follow-up visits at 6 and 12 months, and the proportion of patients achieving a target value of < or =7.0% at 12 months. Since a greater emphasis on therapeutic intensification began in 1995, we also compared HbA1c values and clinical management in 1995-1996 with that of 1992-1994. RESULTS: HbA1c averaged 9.3% on presentation. After 12 months of care, HbA1c values averaged 8.2, 8.4, 8.5, 7.7, and 7.3% for the 1992-1996 cohorts, respectively, and were significantly lower compared with values on presentation (P < 0.0025); the average fall in HbA1c was 1.4%. The percentage of patients achieving a target HbA1c < or =7.0% improved progressively from 1993 to 1996, with 57% of the patients attaining this goal in 1996. Mean HbA1c after 12 months was 7.6% in 1995-1996, significantly improved over the level of 8.4% in 1992-1994 (P < 0.0001). HbA1c levels after 12 months of care were lower in 1995-1996 versus 1992-1994, whether patients were managed with diet alone, oral agents, or insulin (P < 0.02). Improved HbA1c in 1995-1996 versus 1992-1994 was associated with increased use of pharmacologic therapy CONCLUSIONS: Structured programs can improve glycemic control in urban African-Americans with diabetes. Self-examination of performance focused on overcoming clinical inertia is essential to progressive upgrading of care.

Diabetes and obesity in the Louisiana Coushatta Indians.

OBJECTIVE: In order to assist their community in planning intervention and prevention programs, prevalence rates for diabetes and obesity were examined among the Louisiana Coushatta. RESEARCH DESIGN AND METHODS: Coushatta individuals participated in a health survey (questionnaires and physical examinations). Those without known diabetes underwent oral glucose tolerance testing and were classified as having normal glucose tolerance (NGT), impaired glucose tolerance (IGT), or diabetes mellitus (DM). Those with known DM had the diagnosis confirmed by history and/or elevated hemoglobin A1c. Waist-to-hip ratio (WHR), body mass index (BMI), and percent body fat (%BF) were determined as measures of central adiposity and obesity. Prevalence rates of diabetes and obesity among those examined were calculated. The prevalence of those with more than one anthropometric index positive for obesity was also determined. RESULTS: The prevalence of DM was 30% and IGT was 17% among the first 151 Coushatta participants. For males, the prevalence of obesity was 62%, 57%, and 52%, and for females, 59%, 54%, 45%, as determined by the BMI, %BF, and WHR, respectively. Obesity was more prevalent among those with glucose intolerance (IGT + DM) than those with NGT, and those who were obese had the highest prevalence of glucose intolerance. A greater percentage of those with glucose intolerance had more than one positive obesity measure as compared to those with NGT, and those with more than one index consistent with obesity had a greater prevalence of IGT + DM. CONCLUSIONS: Prevalence rates of DM and obesity are high among the Louisiana Coushatta, and obesity is associated with glucose intolerance. Clustering of the three obesity measures occurs in a high percentage of individuals. Data from the current survey are providing information that is being used by the Coushatta community for health planning and development of intervention and prevention programs.

What do internal medicine residents need to enhance their diabetes care?

OBJECTIVE: To identify areas that should be targeted for improvement in care, we examined internal medicine resident practice patterns and beliefs regarding diabetes in a large urban hospital outpatient clinic. RESEARCH DESIGN AND METHODS: Internal medicine residents were surveyed to assess the frequency at which they performed key diabetes quality of care indicators. Responses were compared with recorded performance derived from chart and laboratory database reviews. Resident attitudes about diabetes were determined using the Diabetes Attitude Survey for Practitioners. Finally, an eight-item scale was used to assess barriers to diabetes care. RESULTS: Both self-described and recorded performance of recommended diabetes services short of national recommendations. For yearly eye examinations and lipid screening, recorded performance levels were similar to trainees' reports. However, documented inquiries about patient self-monitoring of blood glucose, performance of foot examinations, and urine protein screening were lower than trainees' reports. Some 49% of the residents selected a target HbA1c of 6.6-7.5% as an attainable goal, yet half of the patients using oral agents or insulin had HbA1c values > 8.0%. No differences in self-described or recorded performance were found by year of training. Most residents did not perceive themselves to need additional training related to diabetes care, and residents were generally neutral about patient autonomy. Patient nonadherence and time constraints within the clinic were most often cited as barriers to care. CONCLUSIONS: The study identifies several areas that require improvement in resident care of diabetes in the ambulatory setting. Because experience during training contributes to future practice patterns, developing a program that teaches trainees how to implement diabetes practice guidelines and methods to achieve optimal glycemic control may be key to future improvements in the quality of diabetes care.

Genetic studies suggest a multicentric origin for Hb G-Coushatta [beta22(B4)Glu-->Ala].

Hb G-Coushatta [beta22(B4)Glu-->Ala] is found in geographically separated ethnic groups. Commonest along the Silk Road region of China but also present in the North American Coushatta, we sought to determine whether this variant had a unicentric or multicentric origin. We examined the haplotype of the beta-globin gene cluster in two Chinese families and in five Louisiana Coushatta heterozygous for this mutation. Chinese and Louisiana Coushatta had different haplotypes associated with the identical Hb G mutation. These haplotypes were defined by the presence of a HindIII restriction site in the Agamma-globin gene and AvaII restriction site in the beta-globin gene in Chinese subjects and their absence in the Louisiana Coushatta. We found a CAC at codon beta2 (beta-globin gene framework 1 or 2) linked to the Hb G-Coushatta gene in Chinese, and a CAT (framework 3) in Louisiana Coushatta, indicating different beta-globin gene frameworks. Both the Hb G-Coushatta mutation (GAA-->GCA) and the codon 2 CAC-->CAT polymorphism are normal delta-globin gene sequences, suggesting the possibility of gene conversion. We conclude that Hb G-Coushatta had at least two independent origins. This could be due to separate mutations at codon beta22 in Chinese and Louisiana Coushatta, a mutation at this codon and a beta-->delta conversion, or two beta-->delta gene conversion events.

Outpatient diabetes management of Medicare beneficiaries in four Mississippi fee-for-service primary care clinics.

BACKGROUND: As part of a quality improvement initiative aimed at increasing physician compliance with standards of care for diabetes patients, diabetes practice patterns among Medicare beneficiaries in four primary care clinics were examined in Mississippi. METHODS: Retrospective chart reviews of Medicare beneficiaries with a diagnosis of diabetes were conducted to examine physician compliance with recommended diabetes monitoring services. RESULTS: Fifty-three percent of all beneficiaries did not have a recorded A1c test while 54 percent did not have a recorded foot exam. The percentage without foot exams decreased with quarterly visits. Seventy-two percent and 68 percent of patients had testing for lipids and proteinuria, respectively, although variability in types of testing performed was seen. Seventy-six percent of beneficiaries did not have a referral for a dilated eye exam. CONCLUSIONS: The study has uncovered, within several primary care sites in Mississippi, variable documentation of compliance with many clinically relevant recommendations relating to the care of elderly patients with diabetes. These items can be targeted for improvement as part of a statewide quality improvement initiative for Medicare beneficiaries.

Use of the Physician Insurers Association of America database as a surveillance tool for diabetes-related malpractice claims in the U.S.

OBJECTIVE: To examine the available national surveillance data on malpractice claims associated with diabetes and to determine the medical specialties having the highest number of claims and the classes and costs of filed claims relating to diabetes. RESEARCH DESIGN AND METHODS: Data was abstracted from the Data Sharing Reports (DSRs) of the Physicians Insurers Association of America (PIAA), as well as a search of the PIAA's computerized database for the period spanning 1 January 1985 to 31 December 1996. Data on numbers of claims, medical causes of loss, indemnity paid, demographics of claimants and physicians, severity, and medical specialties with diabetes-related claims were available. RESULTS: A total of 906 diabetes claims were reported to PIAA, and the total indemnity paid was $26,892,848. A significant downward trend (P = 0.004) was noted for the period between 1993 and 1996. Diabetes claimants were older and predominantly male, relative to all claimants. Ophthalmology, internal medicine, and general and family practice had the highest rates of reported claims at 16.5, 13.6, and 13.4 diabetes claims per 1,000 claims, respectively. Of the diabetes-related injuries, 44% occurred in the practitioners office, as compared with 27% for all claims. A greater proportion of diabetes claims were associated with the highest level of severity of injury with respect to all claims compiled by the PIAA. CONCLUSIONS: The database of the PIAA can be a useful resource to monitor trends in diabetes-related malpractice. Further study into whether claims result from lack of adherence to practice guidelines is needed. Prevention programs designed to reduce the liability among high-risk specialties may also lead to improved care for the patient with diabetes.

Effects of sickle cell trait and hemoglobin C trait on determinations of HbA1c by an immunoassay method.

OBJECTIVE: A number of studies, including the Diabetes Control and Complications Trial (DCCT), have shown that good glycemic control, as assessed by GHb measurements, can reduce the chronic complications of diabetes. The National Glycohemoglobin Standardization Program (NGSP) was established to insure that GHb measurements by different methods were comparable and could be related to the candidate reference method used in the DCCT. The measurement of HbA1c in patients with Hb variants is one area not directly addressed by the NGSP. Therefore, we assessed the comparability of two DCCT-traceable methods in samples with Hb variants. RESEARCH DESIGN AND METHODS: Samples containing HbAA, HbAC, and HbAS were collected from diabetic and nondiabetic patients. HbA1c concentrations were measured by a high-performance liquid chromatography method (Bio-Rad Diamat) and an immunoassay that is suitable for use in a physician's office (Bayer DCA 2000). RESULTS: The two methods compared well for samples with HbAA and HbAS. However, for samples containing HbAC the immunoassay method showed relative positive biases of 8.4 and 10.4% at HbA1c levels of 7 and 9%, respectively, such that the two methods would not be judged comparable according to NGSP guidelines. CONCLUSIONS: The DCA 2000 HbA1c immunoassay method showed significant positive bias in patients with HbC trait. One possible clinical implication of this overestimation is overly rigorous glycemic control with a concomitant increase in hypoglycemia. This may be especially important in certain ethnic populations, such as African-Americans, who have a relatively high prevalence of HbC trait.

Comparison of four commercial urinary albumin (microalbumin) methods: implications for detecting diabetic nephropathy using random urine specimens.

The results of four urinary albumin methods used to identify patients with early diabetic renal disease were compared using random urine samples from healthy and diabetic patients. These methods were the Beckman Array and Behring BNAI immunonephelometric methods, the Dade aca particle-enhanced turbidimetric inhibition immunoassay method, and the INCSTAR SPQ immunoturbidimetric method. The albumin/creatinine ratio reference interval was found to be 2-20 mg albumin/g creatinine (mg/g) for the Array and 3.5-27.5 mg/g for the aca method. All four methods were compared using urines from a group of diabetic and nondiabetic patients. The BNAI, SPQ and Array methods compared well with one another while the aca demonstrated a positive bias of almost 60% at the 30 mg/g and 300 mg/g levels with certain lots of reagent and calibrator. Calibrator cross-over experiments demonstrated that some of the positive bias of the aca method could be accounted for by calibrator differences.

Caloric intake and weight gain of rats depends on endogenous fat preference.

Within outbred colonies, subpopulations of rats exist that exhibit inherent preferences for one type of macronutrient over another (e.g., fat vs. carbohydrate). Prior investigations into the effect of dietary manipulations on consumption or weight gain have not taken into account endogenous macronutrient preferences. The purpose of this study was to examine whether inherent fat preferences translate into differences in caloric consumption and weight gain in rats when fed high-fat and high-carbohydrate diets. Rats that exhibited a preference for fat were identified using a previously described paradigm and were subsequently placed on either a high-fat or high-carbohydrate diet. Daily caloric intakes and weekly weights were monitored over a 28-day period and compared with data for animals with a low-fat preference on the same diets. By the conclusion of the study, the low-fat-preferring rats on the high-carbohydrate diet had consumed significantly more calories than the high-fat-preferrers maintained on the same diet. In contrast, the amounts of calories consumed on the high-fat diet were not significantly different between the low- and high-fat-preferring animals. Those animals with a preference for fat placed on a high-carbohydrate diet weighed significantly less by the end of study, even though they consumed the same number of calories as animals on the high-fat diet. We conclude that the outcome of nutritional studies designed to examine caloric intake and weight gain can be influenced by the innate macronutrient preference of the animal.

Lipoprotein (a) levels in African-Americans with NIDDM.

OBJECTIVE: The purpose of this study was to investigate possible relationships between lipoprotein (a) [Lp(a)] levels and NIDDM in African-Americans. The objectives were to identify associations between Lp(a) levels of subjects with and without NIDDM and to determine the influence of glycemic control, determined by GHb, and of mode of therapy on Lp(a) levels. RESEARCH DESIGN AND METHODS: We studied [4] African-American subjects, 103 with NIDDM and 38 without NIDDM. Their Lp(a) levels, GHb levels, and apolipoprotein (a) [apo(a)] isoforms were determined. Clinical information, including mode of therapy (sulfonylurea, insulin, or no pharmacological therapy), date of diagnosis, and medical history, was obtained by chart review and patient interview. RESULTS: There was no significant difference in median Lp(a) levels between the non-NIDDM (25.5 mg/dl) and NIDDM (24.0 mg/dl) study subjects. No statistically significant difference was found in Lp(a) levels when NIDDM patients with GHb < 12.3% were compared to those with GHb > or = 12.3% (P = 0.096). An inverse relationship was found between apo(a) root-mean-square isoform size and Lp(a) level (r2 = 0.091, P = 0.0035). Analysis of the cases by mode of therapy indicates that there is evidence of an increased median level of Lp(a) in African-Americans with NIDDM on insulin therapy relative to those on sulfonylurea (34.0 vs. 16.0 mg/dl; P = 0.013) and to nondiabetic subjects (34.0 vs. 25.5 mg/dl; P = 0.043). CONCLUSIONS: We conclude that the level of plasma Lp(a) is higher in African-Americans with NIDDM who are being treated with insulin when compared to those on sulfonylurea therapy and to those who are non-NIDDM subjects, and this does not seem to be due to genetic variance or method bias.