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Biomedical subjects

L B Gardner

Publications and source records attributed to L B Gardner.

At least 19 recordsLinked to original sources
PubMed1995

Adverse selection among multiple competing health maintenance organizations.

This study examines risk selection among nine health plans competing for 16,182 employees of one large firm in 1989: one conventional fee-for-service plan, one group-model health maintenance organization (HMO), and seven network and independent practice model HMOs. We develop and compare measures of risk using weights based on HMO and fee-for-service expenditure data, respectively. We use a multiequation statistical model to develop two sets of utilization and expenditure weights for enrollees in each plan. One set of weights, based on discharge abstracts and outpatient records from the large group-model HMO, measures how much each of the nine groups of employees and dependents would have spent, had they been enrolled in a stringently managed plan with no consumer cost sharing. The other set of weights, based on fee-for-service claims data, measures how much each group would have spent, had it been enrolled in an unmanaged health plan with significant coinsurance and deductibles. Predicted annual expenditures per enrollee exhibit a 23% range from lowest (favorable selection) to highest (adverse selection) risk plans using the HMO weights and a 17% range using fee-for-service weights. The fee-for-service plan and group-model HMO with large enrollments have risk mixes near the center of the spectrum. Smaller HMOs exhibit the extreme forms of both favorable and adverse selection. The statistical methods adopted in this study can be used to risk-adjust capitation payments to competing health plans. As mergers among HMOs and group purchasing arrangements among employers increase the average enrollment in each plan from each payor, however, risk differences among plans will be attenuated and the need to risk-adjust payments will be less severe. Key words: health insurance; adverse selection; managed competition; health maintenance organization.

Actuarial Analysis↗
PubMed1993

Insulin and glucose suppress hepatic glycogenolysis by distinct enzymatic mechanisms.

Both insulin and hyperglycemia can effectively suppress hepatic glucose output (HGO). We examined whether insulin and hyperglycemia specifically suppress liver net glycogen breakdown in a rat model in which glycogen is the major source of HGO. We further examined whether insulin and hyperglycemia act by similar or distinct enzymatic mechanisms. HGO, the rate of net glycogen loss, and glycogen phosphorylase and synthase activities were measured in fed, anesthetized rats infused with saline or insulin (7 mU/min/kg) while either maintaining plasma glucose at basal (7.8 +/- 0.2 mmol/L, euglycemic clamp [EC]) or at 10 mmol/L above basal (18 +/- 0.4 mmol/L, hyperglycemic clamp [HC]). During the basal period, the rate of HGO in each group was comparable to the rate of net glycogen breakdown, averaging 76 +/- 9 and 75 +/- 5 mumol/min/kg, respectively. Thus glycogen breakdown appeared to be a major source of ongoing HGO. Over the last 60 minutes of the experimental period, the rate of glycogenolysis averaged 69 +/- 8 mumol/min/kg in saline-treated rats; this could account for about 80% of the total HGO. During both EC and HC studies, HGO was suppressed (5.5 +/- 3 and -3.6 +/- 10 mumol/min/kg, respectively; P < .001 for each). Net glycogen breakdown decreased by 50% in EC rats (P < .05) and ceased in HC rats (P < .001). Glycogen synthase was predominantly in the active form in all three experimental groups (87% +/- 2%, 89% +/- 2%, and 95% +/- 3% in saline, EC, and HC rats, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Severe cerebral edema in a patient with anasarca and hypernatremia.

We describe a woman whose fatal post-liver transplantation cerebral edema was unexpected and of unusual pathogenesis. Her severe cerebral edema is of considerable pathophysiologic interest: 1) it developed in the setting of marked anasarca and persistent hypernatremia, and 2) although hepatic function was poor, it was not considered sufficiently deranged to induce cerebral edema. Furthermore, there was no histologic evidence of hepatic rejection or antemortem hepatic necrosis. We postulate that an impairment of the blood brain barrier in association with a degree of hepatic dysfunction insufficient by itself to cause cerebral edema permitted the brain interstitial fluid volume to increase pari passu with ECF expansion. Cytotoxic cerebral edema and vascular engorgement may also have contributed to a life-threatening increase in intracranial pressure.

Adult↗
PubMed1991

Detection of clinically suspected deep vein thrombosis using light reflection rheography.

Venography is the current standard for the diagnosis of deep vein thrombosis (DVT). Noninvasive tests have differing sensitivity and specificity, are technically demanding, and may be subject to variability in interpretation. Light reflection rheography (LRR) is a noninvasive method utilizing light-emitting diodes and a sensor to measure light reflected from the skin surface. The intensity of reflected light establishes a graphic pattern that indirectly quantifies parameters of venous function by measuring changes in the microcirculation. Seventy-two patients who underwent contrast venography at our institution were also evaluated with LRR. Twenty-four patients were found to have DVT as demonstrated by venography. Of these, 23 also had DVT detected by LRR. No evidence of thrombus was seen in 45 patients studied by venography; in this group, 35 had normal venous emptying indicated by LRR. Using LRR, a sensitivity of 96% was achieved in the evaluation of clinically suspected DVT. This sensitivity is comparable with other noninvasive tests. In addition, LRR is easy to operate, portable, inexpensive, and not technically demanding. Further investigation is needed to confirm these data and further define the role of LRR in the evaluation of clinically suspected DVT.

Adult↗
PubMed1991

A method for risk-adjusting employer contributions to competing health insurance plans.

Biased selection can threaten the viability of multiple choice health systems unless payments to particular plans are adjusted to offset risk differences among employees. We report the results of a study designed to predict medical care utilization and expenditures for groups of fee-for-service plan (FFS) and health maintenance organization (HMO) enrollees, using characteristics commonly available in the personnel files of large employers. Simulation analyses indicate that the six-equation, maximum likelihood model predicts well for groups of 1,000 or more. Additional data are required to reduce prediction errors for smaller groups. This new methodology potentially allows risk-rating of employer contributions to competing health plans, based on the expected utilization of the individuals choosing each plan.

Economic Competition↗
PubMed1990

Services and charges by PPO physicians for PPO and indemnity patients. An episode of care comparison.

Physicians who participate in preferred provider organizations (PPOs) usually agree to various types of utilization review and sometimes discount their charges or agree to accept lower fees. This study was performed to determine whether they provided more or fewer services to their PPO patients than to their indemnity patients and whether the discounting resulted in lower expenditures for each episode of illness. In 1984, Metropolitan Life offered PPO coverage to Dade County (Florida) school board employees and dependents but only a standard indemnity plan to Dade County government employees and dependents. Episodes of care were examined for patients with chest pain, hypertension, joint pain, gastrointestinal or liver disorders, and lower back pain cared for by physicians who treated patients in both the PPO and indemnity employee groups. For PPO patients, charges per physician service were the same or lower, but total physician charges during an episode were higher. For services such as laboratory tests, diagnostic x-rays, and room and board, PPO and indemnity patients' charges were not significantly different.

Fees, Medical↗
PubMed1988

Diagnostic variability in suspected pulmonary embolism.

Over a 12-month period, we observed adult patients with suspected pulmonary embolism referred for lung scanning to determine variability in the diagnostic process. Among 269 studies, 157 lung scans were judged necessary by predetermined criteria. Ninety-three of these 157 patients had inconclusive results (low probability, intermediate probability, or indeterminate). Of these 93 patients, 42 had pulmonary angiograms, ten of which were positive. Of the 51 patients with necessary but inconclusive scans, five were poor candidates for angiography, 15 had other indications for anticoagulation, seven refused the study, and 24 had physicians who considered further studies unwarranted. Patients with and without pulmonary angiography were demographically and clinically similar. Although confirmatory testing such as pulmonary angiography was used frequently (45%) after an inconclusive lung scan, the question of pulmonary embolism was often left unanswered (55%). Methods for linking clinical judgment to lung scan results are necessary to select proper patients for invasive confirmatory testing.

Adult↗
PubMed1988

Effects of low- and high-repetition resistive training on lipoprotein-lipid profiles.

Thirty-seven healthy untrained males (age = 21 +/- 1 yr; range = 19 to 35 yr) were studied to determine the effects of 10 wk of low- and high-repetition resistive training on lipoprotein-lipid profiles. Subjects were assigned to 1 of 3 groups: a low-repetition group (N = 15) that trained using 4 to 6 repetitions maximum or a high-repetition group (N = 14) that used 14 to 16 repetitions maximum in their training or to an inactive control group (N = 8). The number of sets was adjusted to equalize workloads. Muscular strength increased significantly in both training groups as indicated by the increase in the one-repetition maximum test (P less than 0.05). VO2max, body weight, and percent body fat did not change in either of these groups. However, fat-free weight increased significantly in both training groups (both P less than 0.05). The low-repetition training program resulted in no significant changes in the plasma concentrations of triglycerides (104 +/- 15 vs 89 +/- 8), total cholesterol (150 +/- 7 vs 141 +/- 6), high-density lipoprotein (HDL)-cholesterol (40 +/- 1 vs 41 +/- 2), and HDL2-cholesterol (7 +/- 1 vs 7 +/- 1). A similar pattern was observed for the high-repetition group ([i.e., no significant changes in the concentrations of triglycerides (87 +/- 10 vs 89 +/- 8), total cholesterol (148 +/- 6 vs 162 +/- 6), HDL-cholesterol (40 +/-2 vs 40 +/- 2), and HDL2-cholesterol (6 +/- vs 1 vs 7 +/- 2)]. All lipid values were expressed in milligrams per deciliter (mean +/- SE).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Clinical value of the creatinine clearance before the administration of chemotherapy with cisplatin.

The creatinine clearance was calculated in standard fashion from a timed urine specimen (measured creatinine clearance [MCC]) and from a previously published formula (estimated creatinine clearance [ECC]), in 55 instances, in 19 consecutive patients who were admitted to the hospital for treatment with cisplatin. Using creatinine excretion as an index of completeness of urine collection, there were 19 (35%) inaccurate collections. The correlation between creatinine clearances calculated by both methods was excellent (r = 0.684, P less than .001) and improved when inaccurate collections were excluded (r = 0.922, P less than 0.001). A discrepancy between the two methods of 25% or more was found in 19 collections. Using data from patients with two or more collections to test whether or not the two methods produced equally variable results, indicated that the MCC is a more variable, less reliable method than the ECC. In eight of 55 urine collections, the results of MCC were not used as a guide to chemotherapy and, in an additional 16 should have not been used because of inaccuracy in the urine collection. These results suggest that the creatinine clearance as calculated by an alternative method (ECC) should replace the use of MCC when assessment of the renal function is needed before the administration of nephrotoxic agents.

Adult↗
PubMed1987

Attribute frequency and misclassification bias.

Allowances for potential misclassification bias were performed for three epidemiologic studies. Although the error rates were assumed to be identical for the three studies, there were differences in the degree and even in the direction of the bias. It is shown that they are the result of differences in the true frequencies of the misclassified attributes in these studies. In this regard, the relation of misclassification bias to predictive value is described. Misclassification bias is highly dependent upon the interactions between error rates and the true frequencies of attributes. In general, relative risk estimates are more subject to substantial bias from disease misclassification when cohort studies have very low disease frequencies. Odds ratio estimates are more likely to be substantially biased from exposure misclassification when case-control studies have either very high or very low exposure frequencies. Attribute frequency is an important determinant of bias from misclassification.

Epidemiologic Methods↗
PubMed1985

Decision to adopt new medical technology: a case study of thrombolytic therapy.

New medical technologies are adopted by practising physicians at varying rates. Thrombolytic therapy is an example of a technological advance that many physicians have seemed reluctant to employ. A random sample of board certified internists was surveyed by mail to study factors that influence decisions to use thrombolytic agents. Variables important in predicting use were identified by discriminant analysis. In general users and non-users had similar assumptions about the risks and benefits of this technology. Among the important predictor variables were a perception of having patients suitable for treatment, availability of the agents and self-rating of knowledge about this therapy. Among questions related to type of practice and education, only subspecialization and textbook reading were important discriminators. These results suggest that decisions to adopt new technologies do not follow simply from risk-benefit assessments.

Adult↗
PubMed1984

Serum folate and vitamin B12 levels in patients with small cell lung cancer.

Serum folate and vitamin B12 levels were evaluated in 80 patients with small cell lung cancer at diagnosis and during therapy over a 30-week period. Approximately one half of the patients were randomized to receive hyperalimentation. Folate and vitamin B12 intake was adequate without parenteral nutrition in these cancer patients. Serum folate and Vitamin B12 levels did not correlate with disease extent. At the initiation of therapy, serum folate declined with increasing weight loss. During therapy, the intake of folate was adequate to maintain a normal serum folate despite marked weight loss.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

Cocaine-packet ingestion. Diagnosis, management, and natural history.

We treated 50 patients who ingested packets of cocaine and developed a protocol for conservative medical management. Of the 50 patients, only 3 required emergency surgery. Surgery was precipitated by signs and symptoms of bowel obstruction in all cases. Six patients chose elective surgery. The rest of the patients passed the packets without signs of cocaine toxicity or other complications. This finding is in contrast to that of previous reports. Asymptomatic patients who have ingested packets of cocaine can be safely observed and managed conservatively.

Adult↗
PubMed1982

A description of a means of improving ambulatory care in a large municipal teaching hospital: a new role for nurse practitioners.

We describe a nurse practitioner program that has improved ambulatory care in a large municipal teaching hospital. The significant feature of this program is an expanded role for nurse practitioners in the follow-up of patients with complicated illnesses. Benefits of this program include improved continuity of care and an easing of the house staff's service burden. Similar use of nurse practitioners at other municipal teaching hospitals would be a useful approach to problems in quality of care and continuity of care.

Florida↗
PubMed1981

An index predicting relapse and need for hospitalization in patients with acute bronchial asthma.

In an attempt to define guidelines for the assessment of acute asthma, we evaluated 205 patients who presented to the emergency room for treatment of asthma. Of the 205, 120 were successfully treated and discharged from the emergency room, 45 were hospitalized, and 40 were treated and discharged from the emergency room but had relapses within 10 days. A predictive index using a combination of presenting factors was developed: pulse rate greater than or equal to 120 per minute, respiratory rate greater than or equal to 30 per minute, pulsus paradoxus greater than or equal to 18 mm Hg, peak expiratory flow rate less than or equal to 120 liters per minute, moderate to severe dyspnea, accessory-muscle use, and wheezing. The index ranged from 0 to 7, increasing with the severity of symptoms. The index scores of the relapse group (4.9 +/- 1.0) and the admitted group (5.1 +/- 1.0) were both significantly different (p less than 0.001) from that of the successfully treated group (1.6 +/- 1.2). An index of 4 or higher was 95 per cent accurate in predicting the risk of relapse and 96 per cent accurate in predicting the need for hospitalization.

Acute Disease↗