Glycemic control and sliding scale insulin use in medical inpatients with diabetes mellitus.

OBJECTIVE: To identify predictors of hypoglycemic and hyperglycemic episodes in hospitalized patients with diabetes with special attention to the effectiveness of sliding scale insulin regimens. DESIGN: Prospective cohort study. SETTING: Urban university hospital. PARTICIPANTS: One hundred seventy-one adults with diabetes mellitus as a comorbid condition admitted consecutively to medical inpatient services during a 7-week period. MEASUREMENTS: Demographic, clinical, and laboratory data from inpatient medical records. MAIN OUTCOMES: Rates of hypoglycemic (capillary blood glucose, < or = 3.3 mmol/L [< or = 60 mg/dL]) and hyperglycemic (capillary blood glucose, > or = 16.5 mmol/L [> or = 300 mg/ dL]) episodes. RESULTS: Of the patients, 23% experienced hypoglycemic episodes, and 40% experienced hyperglycemic episodes. The overall rates of hypoglycemic and hyperglycemic episodes were 3.4 and 9.8 per 100 capillary blood glucose measurements, respectively. Independent predictors of hypoglycemic episodes included African American race (relative risk [RR], 2.13) and low serum albumin level (RR, 1.92 per 100-g/L decrease); corticosteroid use was associated with a reduced risk of hypoglycemic episodes (RR, 0.32; P < .05). Independent predictors of hyperglycemic episodes included female gender (RR, 1.67), severity of illness (RR, 1.22 per 10 Acute Physiology and Chronic Health Evaluation III units), severe diabetic complications (RR, 2.32), high admission glucose level (RR, 1.33 per 5.5 mmol/L), admission for infectious disease (RR, 2.14), and corticosteroid use (RR, 3.74; P < .05). Of 171 patients, 130 (76%) were placed on a sliding scale insulin regimen. When used alone, sliding scale insulin regimens were associated with a 3-fold higher risk of hyperglycemic episodes compared with individuals following no pharmacologic regimen (RRs, 2.85 and 3.25, respectively; P < .05). CONCLUSIONS: Suboptimal glycemic control is common in medical inpatients with diabetes mellitus. The risk of suboptimal control is associated with selected demographic and clinical characteristics, which can be ascertained at hospital admission. Although sliding scale insulin regimens are prescribed for the majority of inpatients with diabetes, they appear to provide no benefit; in fact, when used without a standing dose of intermediate-acting insulin, they are associated with an increased rate of hyperglycemic episodes.

Effect of potassium supplementation on blood pressure in African Americans on a low-potassium diet. A randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To determine the effect of potassium supplementation on blood pressure in African Americans consuming a low-potassium diet. DESIGN: Randomized, double-blind, placebo-controlled trial with two parallel arms. SETTING: Community-based research site. PARTICIPANTS: Eighty-seven healthy African Americans aged 27 to 65 years with a systolic blood pressure between 100 and 159 mm Hg and a diastolic blood pressure between 70 and 94 mm Hg. INTERVENTION: During the 21-day intervention period, all participants were provided with a low-potassium diet (32 to 35 mmol/d). In addition to this diet, they were randomly assigned to receive either potassium supplements (80 mmol/d) or placebo. MAIN OUTCOME MEASURE: Change in blood pressure in the potassium vs the placebo group, based on a total of nine blood pressure readings at three visits. Blood pressures were taken before and during the intervention by means of random-zero sphygmomanometry. RESULTS: At baseline, the placebo and potassium groups were similar for mean blood pressure (127/78 vs 125/77 mm Hg), 24-hour urinary potassium excretion (50 vs 44 mmol), and all other variables measured (all P > .05). During the intervention, the net difference in 24-hour urinary potassium excretion between groups was 70 mmol. Compared with the placebo group, the potassium supplementation group experienced a net decline in systolic blood pressure of 6.9 mm Hg (95% confidence interval, -9.3 to -4.4 mm Hg; P < .001) and a decline in diastolic blood pressure of 2.5 mm Hg (95% confidence interval, -4.3 to -0.8 mm Hg; P = .004). Simultaneous adjustment for differences in baseline characteristics only strengthened these estimates. CONCLUSIONS: Potassium supplementation reduces blood pressure substantially in African Americans consuming a diet low in potassium. Increased potassium intake may play an important role in reducing blood pressure in this population at high risk for hypertension.

A comparison of statistical and connectionist models for the prediction of chronicity in a surgical intensive care unit.

OBJECTIVE: To compare statistical and connectionist models for the prediction of chronicity which is influenced by patient disease and external factors. DESIGN: Retrospective development of predictive criteria and subsequent prospective testing of the same predictive criteria, using multiple logistic regression and three architecturally distinct neural networks; revision of predictive criteria. SETTING: Surgical intensive care unit (ICU) equipped with a clinical information system in a +/- 1000-bed university hospital. PATIENTS: Four hundred ninety-one patients with ICU length of stay 3 days who survived at least an additional 4 days. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Chronicity was defined as a length of stay > 7 days. Neural networks predicted chronicity more reliably than the statistical model regardless of the former's architecture. However, the neural networks' ability to predict this chronicity degraded over time. CONCLUSIONS: Connectionist models may contribute to the prediction of clinical trajectory, including outcome and resource utilization, in surgical ICUs.

Variable degrees of suppression of hemoglobin S synthesis in subjects with hemoglobin SS disease on a long-term transfusion regimen.

The objectives of this study were to quantify the amount of blood required to suppress synthesis of hemoglobin S (HbS) in patients with hemoglobin SS on a long-term transfusion regimen and to evaluate factors that might contribute to variations in transfusion-induced patterns of responsiveness. Eleven patients with hemoglobin SS (age range, 2 years 4 months to 19 years 9 months) who had had a cerebrovascular accident were monitored during a period of 1 1/2 to 4 years for HbS percentages, reticulocyte percentages, the amount of erythrocytes infused, and weight. From these data the amount of blood necessary to maintain the HbS concentration at less than 30% was expressed as units of packed erythrocytes administered per week per kilogram of body weight. Percentage of HbS were significantly lower in three subjects than in the other eight (6.1 +/- 0.6 vs 23.0 +/- 2.1; p = 0.0009) as were the reticulocyte percentages (2.9 +/- 0.3 vs 7.9 +/- 0.7; p = 0.0021). However, there were no significant differences between pretransfusion hematocrit (0.278 +/- 0.012 vs 0.281 +/- 0.01; p = 0.90) and units of erythrocytes given per week per kilogram (0.0147 +/- 0.0008 vs 0.0156 +/- 0.0009; p = 0.58). Factors explored to define the reason that HbS synthesis was more easily suppressed in some patients than in others included measurements of serum chemistry values and erythropoietin, identification of erythrocyte alloantibodies, and a survey for Howell-Jolly bodies. No significant differences were seen. Although the reasons for the marked variation in transfusion-induced depression of HbS synthesis are unclear, this study emphasizes the importance of determining the units of packed erythrocytes needed per week per kilogram and correlating this value with the pretransfusion HbS percentage. By doing so, one can select the minimal amount of blood necessary to achieve the desired HbS percentage and thereby decrease the risks of transfusion.

Does supplementation of diet with 'fish oil' reduce blood pressure? A meta-analysis of controlled clinical trials.

BACKGROUND: Several lines of evidence suggest that supplementation of diet with omega-3 polyunsaturated fatty acids (omega-3 PUFA), commonly referred to as fish oils, may reduce blood pressure (BP). However, most clinical trials of omega-3 PUFA supplementation have been of insufficient size to detect relevant BP changes. METHODS: We conducted a meta-analysis of 17 controlled clinical trials of omega-3 PUFA supplementation. To estimate an overall effect of omega-3 PUFA supplementation on BP, we calculated the net BP change in each trial (BP delta in omega-3 PUFA group minus BP delta in control group), which was then weighted according to the inverse of the variance. RESULTS: In the 11 trials that enrolled normotensive individuals (n = 728), omega-3 PUFA supplementation led to significant reductions of systolic BP (SBP) and diastolic BP (DBP) in two and one trials, respectively. In the six studies that enrolled untreated hypertensives (n = 291), significant reductions of SBP and DBP were present in two and four trials, respectively. Weighted, pooled estimates of SBP and DBP change (mm Hg) with 95% confidence intervals were -1.0 (-2.0 to 0.0) and -0.5 (-1.2 to +0.2) in the trials of normotensives, and -5.5 (-8.1 to -2.9) and -3.5 (-5.0 to -2.1) in the trials of untreated hypertensives. In 13 of 17 studies, trial duration was less than 3 months. Doses of omega-3 PUFA tended to be high (average dose > 3 g/d in 11 trials). The magnitude of BP reduction was greatest at high BP but was not significantly associated with dose of omega-3 PUFA. Side effects, most commonly eructation and a fishy taste, occurred more frequently in omega-3 PUFA participants than in control participants (28% vs 13%, P < .001). CONCLUSIONS: Our analyses indicate that diet supplementation with a relatively high dose of omega-3 PUFA, generally more than 3 g/d, can lead to clinically relevant BP reductions in individuals with untreated hypertension. However, use of omega-3 PUFA as antihypertensive therapy will require demonstration of long-term efficacy and patient acceptability of lower doses.

The excess incidence of diabetic end-stage renal disease among blacks. A population-based study of potential explanatory factors.

OBJECTIVE: To investigate whether the excess incidence of diabetic end-stage renal disease (ESRD) among African Americans could be explained by racial differences in putative ESRD risk factors. DESIGN: Population-based, ecologic study using the 1981 and 1982 Maryland Statewide Household Hypertension Survey for data on risk factor prevalence. PARTICIPANTS: A total of 2.1 million adults residing within the boundaries of the Maryland Regional ESRD Registry, grouped by race and ZIP code into 26 subpopulations. MAIN OUTCOME MEASURE: Incidence rates of treatment for diabetic ESRD between 1980 and 1985 from the Maryland Regional ESRD Registry by subpopulation. RESULTS: Between 1980 and 1985, 442 persons entered treatment for diabetic ESRD. At the level of the subpopulation, diabetic ESRD incidence was positively associated with black race (relative risk [RR], 3.42; 95% confidence interval [CI], 2.84 to 4.13), prevalence of diabetes (RR, 2.35; 95% CI, 1.92 to 2.87), prevalence of poorly controlled hypertension (RR, 1.80; 95% CI, 1.45 to 1.86), lack of a regular source of health care (RR, 1.82; 95% CI, 1.62 to 2.05), and lower socioeconomic status as indicated by lack of college education (RR, 1.41; 95% CI, 1.32 to 1.52) (all, P < .0001). After adjusting for these risk factors, black race remained strongly associated with the overall incidence of diabetic ESRD (RR, 2.70; 95% CI, 1.89 to 3.86; P < .0001). Further analyses suggested that this excess risk among blacks was confined to ESRD related to non-insulin-dependent diabetes (RR, 4.80; 95% CI, 3.09 to 7.46; P < .0001); blacks were at no higher risk than were whites for ESRD related to insulin-dependent diabetes (RR, 0.90; 95% CI, 0.52 to 1.55; P = .70). CONCLUSIONS: These data suggest that the excess incidence of diabetic ESRD among blacks is not fully explained by a higher prevalence of diabetes or hypertension in blacks or by racial differences in age, socioeconomic status, or access to health care. Instead, they suggest an increased susceptibility to ESRD resulting from non-insulin-dependent diabetes among blacks as compared with whites.

Incidence and risk factors for gout in white men.

OBJECTIVE: To identify potentially modifiable risk factors for the development of gout. DESIGN: Longitudinal cohort study (The Johns Hopkins Precursors Study). PARTICIPANTS: Of 1337 eligible medical students, 1271 (95%) received a standardized medical examination and questionnaire during medical school. The participants were predominantly male (91%), white (97%), and young (median age, 22 years) at cohort entry. OUTCOME MEASURE: The development of gout. RESULTS: Sixty cases of gout (47 primary and 13 secondary) were identified among 1216 men; none occurred among 121 women (P = .01). The cumulative incidence of all gout was 8.6% among men (95% confidence interval, 5.9% to 11.3%). Body mass index at age 35 years (P = .01), excessive weight gain (greater than 1.88 kg/m2) between cohort entry and age 35 years (P = .007), and development of hypertension (P = .004) were significant risk factors for all gout in univariate analysis. Multivariate Cox proportional hazards models confirmed the association of body mass index at age 35 years (relative risk [RR] = 1.12; P = .02), excessive weight gain (RR = 2.07; P = .02), and hypertension (RR = 3.26; P = .002) as risk factors for all gout. Hypertension, however, was not a significant risk factor for primary gout. CONCLUSIONS: Obesity, excessive weight gain in young adulthood, and hypertension are risk factors for the development of gout. Prevention of obesity and hypertension may decrease the incidence of and morbidity from gout; studies of weight reduction in the primary and secondary prevention of gout are indicated.

Does racial variation in risk factors explain black-white differences in the incidence of hypertensive end-stage renal disease?

Prospectively collected data on the incidence of treated hypertensive end-stage renal disease (HT-ESRD) were analyzed to investigate whether the higher rate of HT-ESRD in blacks compared with whites is due to differences in putative ESRD risk factors. The overall age-adjusted relative risks of HT-ESRD for black compared with white residents in the Maryland Regional ESRD Registry (Network 31) Catchment Area were 7.4 (95% confidence interval, 5.9 to 9.4) and 9.9 (95% confidence interval, 7.4 to 13.1) for men and women, respectively. In a population level analysis, race-specific HT-ESRD incidence rates in the black and white populations of 13 regions in Network 31 were related to the prevalence of putative ESRD risk factors in those populations. The latter were estimated from the 1981-1982 Maryland Statewide Household Hypertension Survey. Black populations had a 5.6-fold (95% confidence interval, 3.9 to 8.1) higher unadjusted incidence of HT-ESRD than white populations. The HT-ESRD incidence in a population was also directly related to that population's prevalence of hypertension, severe hypertension, and diabetes mellitus and inversely related to measures of socioeconomic status and mean age at diagnosis of hypertension. When adjusted simultaneously for age, prevalence of hypertension, severe hypertension, diabetes, and level of education, the risk of HT-ESRD was still 4.5 (95% confidence interval, 3.2 to 6.2) times higher for black compared with white populations. Our findings failed to support the hypothesis that race-related differences in the prevalence, severity, or age at onset of hypertension, in the prevalence of diabetes or in socioeconomic status, explain the well-recognized black-white differences in the HT-ESRD incidence.

Factors influencing survival after pancreaticoduodenectomy for pancreatic cancer.

Eighty-nine patients with carcinoma of the head of the pancreas underwent pancreaticoduodenectomies. The actuarial 5-year survival for all 89 patients was 19%, with a median survival of 11.9 months. The 81 hospital survivors were analyzed in an effort to determine factors influencing long-term survival. Negative lymph nodes and the absence of blood vessel invasion both favored long-term survival. The strongest predictive factor was negative lymph node status with a median survival of 55.8 months, compared with 11 months with lymph nodes involved with tumor (p less than 0.05). Blood transfusions were also predictive, with patients receiving two or fewer units having a median survival of 24.7 months, compared with 10.2 months for those receiving three or more units (p less than 0.05). The most important determinant of long-term survival after pancreaticoduodenectomy for pancreatic cancer is biology of the tumor (lymph node status, blood vessel invasion). However, performance of the resection (units of blood transfused) also appears to be an important factor influencing survival.

The accuracy and precision of the Accutracker ambulatory blood pressure monitor.

Prerequisite to the use of ambulatory blood pressure monitors in epidemiologic research is demonstration of a satisfactory level of accuracy and precision. Previous evaluations of these devices raise a number of methodological concerns which complicate interpretation of their findings. Also, important issues regarding the precision of blood pressure measurements and the identification of factors associated with measurement inaccuracies remain unaddressed. To assess the accuracy and precision of the Accutracker ambulatory blood pressure monitor, we obtained five serial estimates of resting blood pressure on 120 ambulatory subjects in The Johns Hopkins Medical Institutions in 1987. Two Accutrackers and two manual observers independently recorded blood pressure with the order determined at random. The fourth observer in each sequence obtained a replicate measurement. For both systolic and diastolic blood pressures, the mean difference between Accutracker and manual measurements was less than 3 mmHg for each pairwise comparison. Scatter plots and regression analyses demonstrated that both Accutrackers tended to underestimate high systolic and diastolic blood pressures. In bivariate and multivariate analyses, increased age was significantly associated with underestimation of systolic blood pressures by both Accutrackers. With respect to the precision of blood pressure measurement, no significant differences were present among the four observers. In summary, our data suggest that the Accutracker has satisfactory accuracy and precision, but that accuracy is not uniform across patient subgroups.

A community-based evaluation of the Vita-Stat automatic blood pressure recorder.

A random sample of ten community-based Vita-Stat automatic blood pressure recorders (ABPR) was evaluated for accuracy and repeatability. Each of 518 adult volunteers had two randomly ordered systolic and diastolic Vita-Stat blood pressure measurements compared with two corresponding measurements obtained by a trained observer using a Random-Zero sphygmomanometer. Eight of the ten Vita-Stat recorders underestimated systolic blood pressure. In contrast, diastolic blood pressure was overestimated by nine of the ten machines. While the overall differences in average blood pressure were small (mean +/- SEM = -2.4 +/- 0.6 mm Hg for systolic blood pressure and +2.3 +/- 0.4 mm Hg for diastolic blood pressure), the magnitude of the average discrepancy varied considerably by machine (+4.7 to -13.8 mm Hg for systolic and +5.0 to -2.0 for diastolic blood pressure). At every level of systolic and diastolic blood pressure the Vita-Stat ABPR provided a less accurate method of classifying blood pressure among individuals than the human observer. Additional analyses exploring the ability of the Vita-Stat machine to measure an individual's blood pressure within 2, 4, or 6 mm Hg of the corresponding Random-Zero value again suggested that the Vita-Stat ABPR was less accurate than the human observer. Duplicate Vita-Stat readings were less repeatable than corresponding Random-Zero measurements. Based on the findings of this study, the Vita-Stat ABPR appears to be an unsatisfactory tool for community-based self-measurement of blood pressure.

Decline in US stroke mortality. Demographic trends and antihypertensive treatment.

Stroke mortality has been falling rapidly in this country since 1973. To investigate age-race-sex effects on stroke mortality, we studied US vital statistics during 1950-1972 and 1973-1981 in 55-64-, 65-74-, and 75-84-year-old race-sex groups. The accelerated rate of decline in stroke mortality since 1973 has had a substantial public health impact, with greater than 200,000 fewer stroke deaths than would otherwise have occurred. For all groups, stroke mortality declined at a greater rate (p less than 0.05) in 1973-1981 than during 1950-1972. The rates of decline during 1973-1981 were greater with increasing age (p less than 0.05) and were more substantial for younger blacks. There were no consistent differences in the rate of decline by sex. The greater rate of decline in absolute stroke mortality in the older age groups and blacks was explained by higher baseline mortality in these groups. Overall, stroke mortality decreased by approximately 2%/yr in 1950-1972 and by approximately 7%/yr after 1973. Rank order of average annual percent decline after 1973 by age-race-sex groups did not correspond to rates of change in treatment or control of hypertension obtained from three national surveys. The accelerated rate of decline after 1973 may have resulted from improved antihypertensive therapy, but our findings fail to confirm this hypothesis and suggest that treatment of hypertension may not be the principal reason for the decline in stroke mortality.

Chlamydia and condylomata acuminata: an update for the nurse practitioner.

The number of cases of the sexually transmitted diseases chlamydia and condylomata acuminata continues to increase. An overview of the diagnosis, treatment, possible disease sequelae, and patient education is presented as an update for the nurse practitioner.