Search PubMed⌕ Search

Biomedical subjects

K Davis

Publications and source records attributed to K Davis.

At least 325 records · Page 18Linked to original sources
PubMed1982

Implications of an expanding supply of physicians: evidence from a cross-sectional analysis.

In the fall of 1980 the Graduate Medical Education National Advisory Committee (GMENAC) issued a report estimating that the supply of physicians will increase by 43% from 1978 to 1990, compared with an increase of 11% in the United States population. GMENAC estimated that this will lead to a surplus of 70,000 physicians by 1990, increasing to 145,000 by the turn of the century. Particularly marked surpluses are estimated to occur for nearly all surgical specialties, as well as most medical subspecialties. This paper attempts to estimate the impact of this increase in the supply of physicians on health care utilization and spending for health care services. Using cross-sectional data for 1978 this study estimates that an increased supply of physicians increases hospital admissions, lengths of hospital stays, costs per hospital day, physician fees for specialty services, and physician expenditures per capita. However, physician incomes appear to be lower in areas with more physicians. Projections to 1990 indicate that total health expenditures may be $50 billion higher as a result of the increase in physician supply. Real incomes of physicians, however, may be no greater than in 1978.

Cross-Sectional Studies↗
PubMed1982

[Comparison of the cumulative survival among patient groups with a left main coronary artery lesion after surgical and therapeutic treatment].

In order to evaluate survival patterns in patients with left main coronary artery (LMCA) disease, 1492 patients with LMCA disease admitted to the U. S. Collaborative Study on Coronary Artery Surgery (CASS) were followed up. Of the 1492 patients, 1183 (79%) underwent coronary artery bypass (CABG) with an operative mortality of 4.2% and an average of 2.7 grafts/patient inserted. Allocation to surgery was by patient and physician preference and not random. Surgical patients generally had more severe angina, a higher prevalence of beta blocker usage, worse ventricular function and more severe LMCA stenosis than medically treated patients. Overall (4 years) survival of the surgical group was 88% compared to 63% in the medical group (p less than 0.001). Other independent predictors of mortality included angiographic left ventricular (LV) dysfunction score, age, % LMCA stenosis, hypertension, dominance, and presence of significant right coronary artery (RCA) stenosis greater than or equal to 50%. CABG was not shown to significantly improve survival in women, in LMCA patients with left dominant circulation, in LMCA patients with non-diseases dominant or balanced RCA circulation or in LMCA patients with greater than or equal to 50% RCA stenosis but good LV function. These data indicate that CABG prolongs life in most patients with left main coronary artery disease, particularly those with severe LMCA narrowing or severe LV dysfunction, however, subgroups of LMCA patients are identifiable who may fare with medical treatment alone.

Aged↗
PubMed1982

[Variability in the interpretation of coronary angiograms by different specialists based on data from the cooperative Coronary Artery Surgery Study].

Randomly selected cine arteriographic films of 30 diseased patients were read twice by each of three experienced observers. The intrareader variability was less than one-half of the interreader variability in reading the stenosis of segments of the coronary anatomy - a statistically significant difference (p less than 0.001). When extent of disease was evaluated by the number of diseased vessels, interreader variability was larger than intrareader variability (p less than 0.01). One reader read considerably less disease than the other two readers. The films were rated as to quality of the arteriographic films and the completeness of the study. In each case there was a greater interreader than intrareader variability (p less than 0.01). The films were rated good, acceptable, or poor. One of the three interpreters consistently gave worse ratings than the other two readers. It was particularly noteworthy that a larger amount of interreader variability was observed in both the left main coronary artery and the proximal left anterior descending artery.

Canada↗
PubMed1981

Effect of coronary bypass surgery on survival patterns in subsets of patients with left main coronary artery disease. Report of the Collaborative Study in Coronary Artery Surgery (CASS).

The 3 year cumulative survival rate of 1,492 patients with left main coronary artery disease (50 percent or greater stenosis of luminal diameter) enrolled in the Collaborative Study in Coronary Artery Surgery (CASS) was 91 percent for the surgical group and 69 percent for patients treated medically (p less than 0.0001). Mortality was significantly greater in patients with impaired left ventricular function. The difference between medical and surgical therapy was significant for patients who had normal, moderately abnormal and severely impaired left ventricular function and for patients with stenosis of the left main coronary artery of 50 to 59, 60 to 69, 70 to 79 and 80 percent or greater. Aortocoronary bypass surgery did not significantly improve survival in patient subgroups who had (1) a nonstenotic dominant right or balanced coronary circulation, (2) a stenotic dominant right coronary artery and normal left ventricular function, and (3) left main coronary stenosis of 50 to 59 percent and normal or mildly abnormal left ventricular function. The Cox proportional hazards model was used to select baseline variables that were independent predictors of long-time mortality. The model selected left ventricular score, age, congestive heart failure score, hypertension, percent left main coronary arterial stenosis and coronary arterial dominance as the baseline variables most predictive of long-term survival. A clinical and angiographic prognostic risk index developed from these six baseline variables showed significantly improved survival for the surgical cohort in each of four risk categories. In the best and worst risk category, the 3 year survival rate was 97 and 82 percent, respectively, for the surgical group and 85 and 34 percent, respectively, for the medical group (p less than or equal to 0.0002). The data from this observational study show that coronary bypass surgery prolongs life in most patients with left main coronary artery disease, particularly those who have severe narrowing of the left main coronary artery or impaired left ventricular function. The results permit a better understanding of the natural history of left main coronary artery disease and permit a more accurate estimate of long-term survival for individual patients through the use of a clinical-angiographic risk index.

Cardiac Catheterization↗
PubMed1981

Polymorphism in chromosome 4.

Chromosomal analyses were performed on 302 individuals, using QFQ banding techniques to determine the occurrence of heteromorphism of chromosome 4. Two type of heteromorphism were observed, one showing an intensely fluorescent band in the centromere region and the other an intensely fluorescent band in the proximal area of the short arm. No one individual possessed both type of heteromorphism. A higher frequency of chromosome 4 heteromorphism was found in patients with schizophrenia, mental retardation, hyperactivity, developmental delay and speech impediments than in normal individuals.

Adolescent↗
PubMed1981

Serum concentrations of the iodothyronines in elderly subjects: decreased triiodothyronine (T3) and free T3 index.

In four groups of subjects free of thyroid disease, the following determinations were made: serum concentrations of thyroxine (T4), triiodothyronine (T3), reverse T3(rT3) and diiodothyronine (T2), and calculated indices of free thyroxine (FT4) and free triiodothyronine (FT3). Group A comprised healthy subjects aged 16-64; Group B, 24 healthy elderly subjects aged 68-95; Group C, 23 elderly patients with mild well-controlled chronic illnesses, aged 70-85; Group D, 40 nursing home residents aged 66-100. Serum T4 and T2 concentrations and the FT4 index were not affected by age; the rT3 concentration was slightly but significantly elevated only in Group D patients. Serum T3 concentration was significantly lower in all groups of elderly subjects and decreased FT3 index measurements were detected after age 75. It was concluded that old age, without complicating illness, is accompanied only by a decrease in the serum level of T3 and the FT3 index; values for other iodothyronines are unchanged. Clinicians should consider the age-related changes in T3 and FT3 values when interpreting thyroid function tests.

Adolescent↗
PubMed1981

Angiographic prevalence of high-risk coronary artery disease in patient subsets (CASS).

The prevalence of coronary artery stenoses greater than or equal to 70% or left main stenosis greater than or equal to 50% was evaluated in 20,391 patients who underwent angiography in the Coronary Artery Surgery Study from 1975-1979. After the patients with unstable angina or myocardial infarction were excluded, the disease prevalence in the 8157 patients with definite angina, probable angina, and nonspecific chest pain was 93%, 66% and 14% in men and 72%, 36% and 6% in women (p less than 0.001). The age and sex of the patients and character of chest pain were important determinants of disease prevalence and severity. Left main or three-vessel coronary disease occurred in more than 50% of middle-aged men and older women with definite angina and in more than 50% of men who had probable angina and were older than 60 years of age. In contrast, left main coronary disease occurred in less than 2% of 1282 men and less than 1% of 1397 women with nonspecific chest pain regardless of age. In this latter patient subset, less than 5% of men and less than 1% of women in each decade under 60 years had left main or three-vessel coronary artery disease. Thus, high-risk coronary disease is common in middle-aged patients with definite angina and older patients with probable angina, but is rare in patients with nonspecific chest pain. Indications and guidelines for diagnostic noninvasive tests and coronary angiography could be based on these results.

Adult↗
PubMed1980

Operative risk factors in patients with left main coronary-artery disease.

To identify the factors associated with operative mortality, we evaluated clinical, angiographic, and surgical variables in 1172 patients with left main coronary-artery stenoses of at least 50 per cent, who underwent coronary-bypass procedures in the Collaborative Study in Coronary Artery Surgery (CASS). The operative mortality was 4.2 per cent overall and was less than 3 per cent in seven of the 15 participating hospitals. Historical variables associated with an increase in operative mortality were age, female sex, and duration and severity of angina. Other variables associated most closely with poor survival were urgency of operation, left coronary-artery dominance, severity of left main coronary-artery stenosis, and impairment of left ventricular contraction. The results of this multicenter study show that aortocoronary bypass surgery in patients with left main coronary-artery disease can be performed with a low mortality and that patients at high risk can often be identified before surgery.

Age Factors↗
PubMed1980

Interaction of separation discomfort with contact comfort and discomfort in the dog.

This experiment concerns 2 issues: the time of onset of the process of social attachment in the dog, and the nature of the interaction between the emotion of separation distress and that caused by discomfort. The subjects were 48 puppies from 4 genetic backgrounds: beagles, Telomians, and their reciprocal F1 hybrids. Puppies were divided into 4 groups nd isoalted for short periods under comfortable and uncomfortable conditions beginning at 3, 11, 17, and 25 days from birth. The dependent variable was distress vocalization during a 10-min period. Separation distress did not occur before 11 days and remained at a low level until 21 days, when it rose rapidly. The process of attachment is thus initiated in the transition period but does not reach a high level until some 2 weeks later. Interaction between the 2 kinds of affect is compatible and additive.

Animals↗