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Biomedical subjects

D L Simel

Publications and source records attributed to D L Simel.

At least 37 records · Page 2Linked to original sources
PubMed1994

Granulocyte deformability and F-actin content: relationship to diabetes mellitus and retinopathy.

Capillary closure in diabetic retinopathy may be initiated by lumenal occlusion by granulocytes. To determine whether subjects with diabetes mellitus have less deformable granulocytes than healthy subjects, granulocyte deformability was measured by mean entry time into a model capillary system in 16 diabetic-nondiabetic pairs. Granulocyte F-(filamentous) actin content between groups was compared, under basal conditions and after cellular stimulation. The relationship of granulocyte deformability to several diabetes-related variables was examined. Diabetic granulocytes were only 9% +/- 22% less deformable than normal granulocytes (p = 0.16). Deformability was increased in subjects with retinopathy and those with the worst glycemic control (r = 0.61, p = 0.026); both findings were in the opposite direction from that predicted. Basal and stimulated granulocyte F-actin content did not differ between the two groups (p > 0.2 for all assays). Although granulocytes may be important in the pathogenesis of diabetic retinopathy, granulocyte deformability (measured by mean entry time) and F-actin content are not significantly different between healthy patients and those with diabetes.

Actins↗
PubMed1994

The relationship between glycemic control and health-related quality of life in patients with non-insulin-dependent diabetes mellitus.

The relationship between glycemic control and health-related quality of life was examined in patients with non-insulin-dependent diabetes mellitus (NIDDM). Within the context of a randomized controlled trial, 275 patients with NIDDM receiving primary care from a Veteran's Administration general medical clinic were enrolled and monitored for 1 year. Glycemic control (glycosylated hemoglobin levels) and health-related quality of life (Medical Outcomes Study Short-Form 36-item Health Survey [SF-36]) were assessed at baseline and at 1 year. Multivariate regression modeling using baseline and change scores during a 1-year period did not find a linear or curvilinear relationship between glycosylated hemoglobin and SF-36 scores (P = .15); this was true even after controlling for five covariates identified a priori (insulin use, number of diabetic complications, duration of diabetes, education, number of hyper-, or hypoglycemic episodes during the preceding month). Health services researchers and clinicians alike need to be aware that these two important outcomes may not be directly related. This lack of association could contribute to the high noncompliance rates observed among patients prescribed complex diabetic regimens. Unless patients perceive a benefit from following such regimens, good glycemic control may continue to be an elusive therapeutic goal, especially in patients with long-standing disease.

Blood Glucose↗
PubMed1994

A telephone-delivered intervention for patients with NIDDM. Effect on coronary risk factors.

OBJECTIVE: To examine whether a telephone-delivered intervention (TDI), designed to improve glycemic control in patients with non-insulin-dependent diabetes mellitus (NIDDM), improved coronary risk factors in high-risk patients. RESEARCH DESIGN AND METHODS: This randomized controlled trial involved 275 veterans with NIDDM followed in a general medical clinic. Intervention (TDI) patients were telephoned at least monthly by a nurse. Calls emphasized compliance with the medical regimen (diet, medications, and exercise), encouraged behavioral changes, and facilitated referrals to a dietitian or smoking cessation clinic. Control patients received no such calls. Baseline and 12-month follow-up measurements included fasting lipid profiles, weight, smoking status (self-reported; cessation verified by measurement of exhaled CO), adherence to diet and exercise (self-reported), appointments, and medications (hospital computerized data base). RESULTS: After 12 months, equal numbers of obese patients in the two groups reported adhering to a diabetic diet and exercising, although more obese TDI patients had seen a dietitian (30 vs. 7%, P = 0.003). Weight loss was not seen in either group (-0.9 +/- 5.3 vs. -0.1 +/- 3.6 kg, P = 0.202). Hyperlipidemic TDI patients were more likely to see a dietitian (31 vs. 6%, P = 0.003) and receive lipid-lowering medications (22 vs. 9%, P = 0.096), but serum cholesterol reduction was similar between groups (-11.7 +/- 33.4 vs. -4.3 +/- 32.7 mg/dl, P = 0.270); comparable results were seen for high-density lipoprotein, low-density lipoprotein, and triglyceride levels. More TDI group smokers reported quitting (26 vs. 0%, P = 0.033), but the difference was not significant for CO-verified abstention (10 vs. 0%, P = 0.231). CONCLUSIONS: The TDI improved self-reported adherence to regimens that might reduce coronary risk, but had little effect on objective measures of risk.

Blood Glucose↗
PubMed1993

Diagnosis of obstructive airways disease from the clinical examination.

OBJECTIVE: To determine the operating characteristics of history and physical examination items for pulmonary airflow obstruction. DESIGN: Prospective observational study. SETTING: Medical Preoperative Evaluation Clinic at the Durham Veterans Affairs Medical Center. PATIENTS/PARTICIPANTS: Consecutive patients referred for outpatient medical preoperative risk assessment. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Number of years the patient had smoked cigarettes, patient-reported wheezing [LR+ (likelihood ratio for finding present) = 3.1; LR- (likelihood ratio for finding absent) = 0.58], and auscultated wheezing (LR+ = 12; LR- = 0.87) were independent predictors of obstructive airways disease from the history and physical examination. Forced expiratory time and peak expiratory flow rate, both measured by the clinician at the bedside, were additional independent predictors of airflow obstruction. A nomogram using patient-reported wheezing, number of years the patient had smoked, and auscultated wheezing was developed and validated (area under receiver operating characteristic curve = 0.78; p = 0.0001) for the bedside prediction of obstructive airways disease. Peak expiratory flow rate can be substituted for auscultated wheezing with similar predictive ability. CONCLUSIONS: The results of bedside clinical examinations predict the presence of obstructive airways disease. A nomogram based on a combination of four bedside findings predicts airflow obstruction as well as clinicians' overall clinical impressions.

Aged↗
PubMed1993

The effect of sleeved arms on oscillometric blood pressure measurement.

The authors measured the blood pressures of 36 subjects who had bare and sleeved arms to determine the effect of wearing sleeves on automatic oscillometric blood pressure measurements. They found no statistically significant effect of sleeves on the measurement of either systolic or diastolic blood pressure (p > 0.15). However, based on confidence intervals of possible sleeve effects, the authors recommend repeating blood pressure measurements on bared arms when the sleeved-arm oscillometric measurements are at least 86 mm Hg diastolic or 135 mm Hg systolic.

Adult↗
PubMed1993

Likelihood ratios for continuous test results--making the clinicians' job easier or harder?

Clinicians' paradigms for considering diagnostic test results require decisions based on the actual test value. However, when the test result is reported on a continuous scale each possible outcome may not result in unique actions. To simplify decision making, clinicians often break down the continuous scale into dichotomous or ordered outcomes. Likelihood ratios, reported with the test outcome, help summarize the impact of diagnostic tests. Although commonly applied to dichotomous outcomes, likelihood ratios can also be applied to ordinal or continuous results. This application allows investigators to consider the effect of clinically simplifying continuous data into dichotomous or ordinal categories. The parameters of a simple logistic regression equation summarize continuous likelihood ratios, evaluate covariates, generate likelihood ratio lines, and help assess the statistical significance of more complex models. Having visually inspected likelihood ratio lines and considered statistical differences, the investigator should choose the test report format that best accounts the realities driving clinical decisions.

Diagnosis↗
PubMed1993

Smokeless tobacco use in an outpatient veteran population.

Smokeless tobacco use is a significant health risk for carcinoma of the oropharynx, and has a high prevalence in the southern United States. To evaluate the potential demand for a smokeless tobacco cessation program, we surveyed patients attending the General Medicine Clinic of a Veterans Affairs Medical Center. The prevalence of smokeless tobacco use was 5.8%, which did not justify creation of a clinic-based cessation program. Since we observed adults using smokeless tobacco as a means to reduce or stop their smoking, smoking cessation programs should include counseling against smokeless tobacco use.

Attitude↗
PubMed1992

Clinical evaluation for sinusitis. Making the diagnosis by history and physical examination.

OBJECTIVE: To identify the most useful clinical examination findings for the diagnosis of acute and subacute sinusitis. DESIGN: Prospective comparison of clinical findings with radiographs. SETTING: General medicine clinics at a university-affiliated Veterans Affairs Medical Center. PATIENTS: Two hundred forty-seven consecutive adult men with rhinorrhea (51%), facial pain (22%) , or self-suspected sinusitis (27%) (median age, 50 years; median duration of symptoms, 11.5 days). MEASUREMENTS: Patients were examined by a principal investigator (86%) or by a staff general internist, internal medicine resident (postgraduate year 2 or 3), or physician assistant, all blinded to radiographic results. All examiners recorded the presence or absence of 16 historical items, 5 physical examination items, and the clinical impression for sinusitis (high, intermediate, or low probability). The criterion standard was paranasal sinus radiographs (4 views), which were interpreted by radiologists blinded to clinical findings. RESULTS: Thirty-eight percent of patients meeting entrance criteria had sinusitis. Sensitivity, specificity, and likelihood ratios were measured for clinical items. Logistic regression analysis showed five independent predictors of sinusitis: maxillary toothache (odds ratio, 2.9), transillumination (odds ratio, 2.7), poor response to nasal decongestants or antihistamines (odds ratio, 2.4), colored nasal discharge reported by the patient (odds ratio, 2.2), or mucopurulence seen during examination (odds ratio, 2.9). THe overall clinical impression was more accurate than any single finding: high probability (likelihood ratio, 4.7, intermediate (likelihood ratio, 1.4), low probability (likelihood ratio, 0.4). CONCLUSIONS: General internists, focusing on five clinical findings and their overall clinical impression, can effectively stratify male patients with sinus symptoms as having a high, intermediate, or low probability of sinusitis.

Adult↗
PubMed1991

Likelihood ratios with confidence: sample size estimation for diagnostic test studies.

Confidence intervals are important summary measures that provide useful information from clinical investigations, especially when comparing data from different populations or sites. Studies of a diagnostic test should include both point estimates and confidence intervals for the tests' sensitivity and specificity. Equally important measures of a test's efficiency are likelihood ratios at each test outcome level. We present a method for calculating likelihood ratio confidence intervals for tests that have positive or negative results, tests with non-positive/non-negative results, and tests reported on an ordinal outcome scale. In addition, we demonstrate a sample size estimation procedure for diagnostic test studies based on the desired likelihood ratio confidence interval. The renewed interest in confidence intervals in the medical literature is important, and should be extended to studies analyzing diagnostic tests.

Epidemiology↗
PubMed1991

A randomized controlled trial comparing quantitative informed consent formats.

Informed consent has been indirectly studied only in settings that do not replicate the actual consent process. We designed a sham study and randomly allocated adult ambulatory patients to receive one of two consent forms: Consent A (n = 52) described a randomized trial of usual treatment vs a new medication that "may work twice as fast as the usual treatment"; or Consent B (n = 48) that described a randomized trial of a new medication that "may work half as fast as the usual treatment". Patients randomized to Consent A were more likely to consent than those randomized to Consent B (consent rate A = 67%, consent rate B = 42%, p less than 0.01). Among patients who cited quantitative information, the difference in consent rate was even more marked (95% vs 36%, p less than 0.001); patients who did not cite quantitative information had equivalent consent rates. Patients who perceived minimal or severe symptoms had lower consent rates than those with mid-range symptom scores (chi 2(2) = 8.35, p = 0.015). Patients who recognize quantitative information will use it to make informed consent decisions.

Behavioral Research↗
PubMed1991

Anti-inflammatory effects of pentoxifylline in claudication.

We measured neutrophil elastase/alpha 1 proteinase inhibitor complex (E/alpha) levels by ELISA in plasma samples drawn from 19 patients with claudication, before and at 1 and 2 months after initiation of pentoxifylline (PTF), 400 mg. p.o. tid. Plasma E/alpha levels declined in all eight patients whose initial values were more than 300 ng elastase per ml. Whole blood viscosity (wbv) was reduced by two months' treatment in 12 of 14 patients tested. The relative change in wbv was significantly related to the relative change in E/alpha (R2 = 0.8), for patients with elevated initial E/alpha levels, suggesting a common or related mechanism for the two effects. Plasma crosslinked fibrin D-dimer fragments (XDP) measured by ELISA as indicators of coagulation activity were lower compared to pretreatment levels in 9 of 10 samples drawn when symptoms were improved on PTF, whereas they were increased in 6 of 9 samples drawn when symptoms were worse or unchanged. Plasma viscosity, C-reactive protein and alpha 1-acid-glycoprotein did not change significantly with PTF treatment. Together these findings are consistent with the possibility that reduced microvascular neutrophil activation and coagulation play a role in the clinical efficacy of PTF in intermittent claudication.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1990

Driving-impaired patients leaving the emergency department. The problem of inadequate instructions.

STUDY OBJECTIVE: We evaluated the frequency with which blood alcohol concentrations were obtained in emergency department patients with presumed alcohol impairment, whether physicians counseled impaired patients not to drive, and whether safe transportation was available. DESIGN: Retrospective chart review and search of the North Carolina Driver History file. SETTING: Emergency departments of a university and affiliated Veterans Affairs Medical Center (VAMC). PATIENTS: Consecutive adult patients at the university (n = 1554) and VAMC (n = 1461) emergency departments. Patients with presumed alcohol-induced impairment (university, 75; VAMC, 88) who did not require hospital admission were identified. Presumed alcohol-induced impairment was defined by any of the following: nurse or physician note specifying the patient was intoxicated; indication in the medical record that the patient had alcohol on their breath; claim by the patient of alcohol use the day of evaluation; or measurement of blood alcohol concentration. MEASUREMENTS AND MAIN RESULTS: Blood alcohol concentrations were measured in 80% of presumed alcohol-impaired university patients (median blood alcohol concentration, 45 mmol/L) and 68% of VAMC patients (median blood alcohol concentration, 58 mmol/L). Driving skills deteriorate with blood alcohol concentrations of 11 mmol/L or greater; however, 63% of university and 88% of VAMC patients with measured blood alcohol concentrations of 11 mmol/L or greater were still impaired when discharged. Only 3.5% of university and 8.7% of VAMC patients impaired at discharge were advised not to drive, whereas 31% of university and 20% of VAMC patients impaired at discharge were supervised by a responsible person. The prevalence of previous driving-while-impaired convictions was high (university, 34%; VAMC, 58%). CONCLUSIONS: Presumed alcohol-impaired patients seen in emergency departments frequently have blood alcohol concentrations measured. Despite documented evidence of driving impairment there is little evidence that such patients are counseled not to drive or that safe transportation home is available.

Adult↗