Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Length Of Life”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1995

Cost-utility analysis of group living in dementia care.

A cost-utility analysis (CUA) was applied to group living for dementia patients. A Markov-model of an expected life-length of 8 years was used. Forty-six patients in group living were compared to 39 patients living at home by inclusion and 23 institutionalized patients. When the cost per gained quality-adjusted life-year (QALY) was calculated, the group living alternative was the most favorable for the patients, giving a cost per paired QALY of US dollars < 0. In the extensive sensitivity analysis the main result was consistent but methodological problems were indicated.

Aged↗
PubMed1992

Effects of prolonged growth hormone administration in rats with chronic renal insufficiency.

Recombinant hGH (rhGH) augments short-term linear growth in experimental animals and children with chronic renal failure. Significant augmentation of final height, however, requires prolonged growth hormone therapy during years of growth. The effects of prolonged rhGH treatment on linear growth, progression of renal dysfunction, and longevity in the setting of renal insufficiency are unknown. We examined at 9, 15, and 25 wk growth in length and weight, glomerular filtration rate measured by inulin and creatinine clearance, food efficiency (g ingested/weight gained), and survival in treated (U-GH) and untreated (U) 75% nephrectomized uremic rats and in treated (S-GH) and untreated (S) sham-operated rats. We also measured kidney weight to body weight ratios at the time the rats were killed. Treatment was rhGH 1.0 mg s.c. three times a week during wks 4-12 of life. Length of U-GH rats was greater than that of U rats (p less than 0.05) at 15 and 25 wk (but not at 9 wk) and equal to that of S rats throughout the study. Length of S-GH rats exceeded that of S rats. At 9 wk, weight was diminished in both U and U-GH rats (p less than 0.05) versus S and S-GH rats; by 15 wk, U-GH rat weight was equal to S rat weight. Glomerular filtration rate measured by creatinine was markedly reduced in U and U-GH rats and did not increase in response to prolonged rhGH in either U-GH or S-GH rats. Diminished food efficiency of U rats versus S rats (p less than 0.05) was not improved significantly by rhGH.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Evolutionary aspects of human cancer.

Evolutionary aspects of human cancer can be dealt with at two levels--on the one hand long-term evolution involving hereditary effects between generations; and on the other hand evolutionary processes operating within the organisms between tissues, cells and cell constituents, which also comprise genetic alterations, selection and adaptation. These two levels of evolution can be designated as phylogenetic and ontogenetic evolution, respectively. Concerning phylogenetic evolution there must have been a strong selection against neoplastic diseases occurring at reproductive age and a variety of protective mechanisms against carcinogenic agents have been developed. Cancer is therefore primarily a disease of old age, which does not constitute a significant risk in natural populations for the simple reason that the life length is too short. The development of an individual comprises selection forces between cells and tissues, which are particularly striking for the multistage development of tumours. The accumulation of several genetic alterations in the same cells, as illustrated by the analysis of colorectal tumours, must require a pronounced clonal expansion between each event. Such selective growth effect has recently been demonstrated for the tumour suppressor gene p53 in brain tumours. Cancer often implies a break down of between balanced systems antagonistic forces, such as oncogenes and suppressors of oncogenes. Examples of this are provided by the genetic regulation of metastasis, involving metalloproteinase as well as the inhibitor of metalloproteinase. The immortalization of cells by transformation points to the fact that programmed cell death and the balance between suicide genes and suppressors of such suicide genes is affected.

Apoptosis↗
PubMed2002

Treatment preferences in recurrent ovarian cancer.

OBJECTIVES: In the case of recurrent ovarian cancer, salvage therapy represents the potential to trade off between quality and quantity of life. Patient and physician face a choice between chemotherapy directed at slowing disease progression and supportive or palliative care that focuses on symptom management. To date, no studies have investigated the effects of best supportive care on ovarian cancer patients' quality of life and length of life as compared to salvage therapy. In other cancers, both quantity and quality of life considerations have been shown to affect treatment preferences. METHODS: Using a decision board, we assessed preferences for salvage therapy or palliative care in the case of recurrent ovarian cancer among 81 ovarian cancer patients receiving first-line chemotherapy and 75 Noncancer Controls. RESULTS: Compared to Noncancer Controls, ovarian cancer patients overwhelmingly preferred salvage therapy; quantity of life was of primary importance. In both groups, preference was not related to age, marital status, number of children, or employment status. On average, patients indicated they would switch from salvage therapy to palliative care when the median survival associated with salvage therapy was reduced to 5 months. Noncancer Controls would switch significantly sooner, when the median increment in survival period was reduced to 8 months. Switchpoint was not associated with life satisfaction, quality of life, or psychological or spiritual well-being in either group. CONCLUSIONS: The majority of women, independent of a cancer diagnosis, indicated a desire for continuing aggressive treatment, despite poor outcomes. Quality of life was of secondary importance, especially among ovarian cancer patients.

Aged↗
PubMed2000

Stochastic epidemics in dynamic populations: quasi-stationarity and extinction.

Empirical evidence shows that childhood diseases persist in large communities whereas in smaller communities the epidemic goes extinct (and is later reintroduced by immigration). The present paper treats a stochastic model describing the spread of an infectious disease giving life-long immunity, in a community where individuals die and new individuals are born. The time to extinction of the disease starting in quasi-stationarity (conditional on non-extinction) is exponentially distributed. As the population size grows the epidemic process converges to a diffusion process. Properties of the limiting diffusion are used to obtain an approximate expression for tau, the mean-parameter in the exponential distribution of the time to extinction for the finite population. The expression is used to study how tau depends on the community size but also on certain properties of the disease/community: the basic reproduction number and the means and variances of the latency period, infectious period and life-length. Effects of introducing a vaccination program are also discussed as is the notion of the critical community size, defined as the size which distinguishes between the two qualitatively different behaviours.

Child↗
PubMed2003

An exponential representation of health state utility.

It has been shown which assumptions are reasonable to combine quality of life with length of life, those attributes fundamental to the quality-adjusted life-year concept. One of these assumptions is the so-called "constant proportional tradeoff" which restricts the underlying utility functions for life-years to those consistent with constant proportional risk posture. However, this might be too restrictive because "constant absolute tradeoff" cannot be reflected. Pliskin et al. mentioned this case already and suggested an exponential function as a proper function to reflect the underlying constant absolute risk posture. Its proof is given in the appendix of this article. A survey among tinnitus patients, however, shows that this assumption is less plausible. Further research is needed to confirm that finding.

Journal Article↗
PubMedDate not supplied

Health care economic analyses and value-based medicine.

Health care economic analyses are becoming increasingly important in the evaluation of health care interventions, including many within ophthalmology. Encompassed with the realm of health care economic studies are cost-benefit analysis, cost-effectiveness analysis, cost-minimization analysis, and cost-utility analysis. Cost-utility analysis is the most sophisticated form of economic analysis and typically incorporates utility values. Utility values measure the preference for a health state and range from 0.0 (death) to 1.0 (perfect health). When the change in utility measures conferred by a health care intervention is multiplied by the duration of the benefit, the number of quality-adjusted life-years (QALYs) gained from the intervention is ascertained. This methodology incorporates both the improvement in quality of life and/or length of life, or the value, occurring as a result of the intervention. This improvement in value can then be amalgamated with discounted costs to yield expenditures per quality-adjusted life-year ($/QALY) gained. $/QALY gained is a measure that allows a comparison of the patient-perceived value of virtually all health care interventions for the dollars expended. A review of the literature on health care economic analyses, with particular emphasis on cost-utility analysis, is included in the present review. It is anticipated that cost-utility analysis will play a major role in health care within the coming decade.

Cost of Illness↗
PubMed1997

Incidentalomas. A disease of modern technology.

The optimal strategy for hormonal screening of a patient with any incidentally discovered adrenal or pituitary mass is unknown. Our review of the endocrinologic literature supports the view that such patients are at slightly increased risk for morbidity and mortality. There is a benefit of early diagnosis for at least for some of the disorders, suggesting the importance of case finding. The data in Tables 1 and 4 illustrate that clinically diagnosed hormone-secreting adrenal and pituitary tumors are far less common than incidentalomas. From a clinical perspective, our ability to determine accurately those at increased risk among the vast majority who are not at increased risk is poor. Given the limitations of diagnostic tests, effective hormonal screening requires a sufficiently high pretest probability to limit the number of false-positive results. This condition is met to varying degrees in the patient with an adrenal mass or small incidentally discovered pituitary mass but no signs or symptoms of hormone excess. Even the more common lesions such as pheochromocytoma and prolactinoma are relatively rare. Subjecting patients to unnecessary testing and treatment carries its own set of risks. Initial costs aside, testing may result in further expense and harm as false-positive results are pursued, producing the cascade effect described by Mold and Stein as a "chain of events (which) tends to proceed with increasing momentum, so that the further it progresses the more difficult it is to stop." The extensive evaluations performed in some patients with incidentally discovered masses may reflect the unwillingness of many physicians to accept uncertainty, even in the case of extremely unlikely diagnoses. This unwillingness may be driven, in part, by fear of potential malpractice liability, the failure to appreciate the influence of prevalence data on the interpretation of diagnostic testing, or other factors. Indeed, the major justification for further evaluation of these patients is not so much to avoid morbidity and mortality for rate patients who truly are at increased risk but rather to reassure those in whom further testing is negative (and to reassure ourselves). Physicians must take care not to create inappropriate anxiety in patients by overemphasizing the importance of an incidental finding unless it is associated with a realistic clinical risk. Our recommendations utilize currently available information to minimize the untoward effects of the cascade. As evidence accumulates, recommendations may need to be revised. The benefit of diagnosis of one of these adrenal or pituitary disorders must be considered in the context of the patient's overall condition. Studies are needed to analyze the utility in clinical practice of hormonal screening for these common radiologic findings. We need to use these studies to identify the critical gaps in our knowledge and to adopt the epidemiologic methods of evaluation of evidence that have been applied to preventive measures. We must be careful to recognize lead-time bias in which survival can seem to be lengthened when screening simply advances the time of diagnosis, lengthening the period of time between diagnosis and death without any true prolongation of life. Length bias refers to the tendency of screening to detect a disproportionate number of cases of slowly progressive disease and to miss aggressive cases that, by virtue of rapid progression, are present in the population only briefly. Endocrinologists must avoid the pitfalls of overestimation of disease prevalence and of the benefits of therapy resulting from advances in diagnostic imaging. Clinical judgment based on the best available evidence should be complemented and not replaced by laboratory data.

Adrenal Gland Diseases↗
PubMed2002

Quantitative trait loci for lifespan of mated Drosophila melanogaster affect both sexes.

The properties of alleles at quantitative trait loci (QTLs) contributing to variation in lifespan should be described to determine the mechanisms of evolution of life length and to predict its future changes. Previously, we and others conducted genome-wide screens for QTLs that segregate among one panel of recombinant inbred lines (RILs) using a dense molecular marker map. In non-stressful conditions, QTLs effecting the lifespans of virgin females and males were frequently sex specific. In an unrelated panel of RILs, the effects of QTLs in flies maintained in cages with mixed sexes were similar in both sexes. Here, we re-measured the lifespans of the former panel of RILs in cages with mixed sex cohorts. Lifespan declined owing to mating. The amount of decline correlated between sexes within lines. QTLs mapping to the intervals 15A-19C, 50B-57C, 63A-65A, and 96F-99B had similar effects on the lifespans of both males and females. These QTLs have previously been detected in virgin flies surveys and had sex- and/or environment-specific effects.

Animals↗
PubMed2001

The goals of medicine. Towards a unified theory.

The purpose of this article is to present a normative theory of the goals of medicine (a theory that tells us in what respects medicine should benefit the patient) that is both comprehensive and unified. A review of the relevant literature suggests that there are at least seven plausible goals that are irreducible to each other, namely to promote functioning, to maintain or restore normal structure and function, to promote quality of life, to save and prolong life, to help the patient to cope well with her condition, to improve the external conditions under which people live, and to promote the growth and development of children. However, it seems that all these goals need to be qualified in different ways, e.g. it does not seem reasonable to improve physiological function or functional ability unless this is expected to have positive effects on quality of life and/or length of life, or to improve the quality of life in any respect, or by any means. These qualifications all suggest that the proposed goals are, as goals, conceptually, and not just causally, related to one another, and that they should therefore not be regarded in isolation. Instead, we should think of the medical enterprise as having a multidimensional goal structure rather than a single goal. In order to depict clearly how the different goals are related to one another, a multidimensional model is constructed.

Activities of Daily Living↗
PubMed2003

Decisions for hospice care in patients with advanced cancer.

OBJECTIVES: To identify factors that may influence the decision of whether to enter a hospice program or to continue with a traditional hospital approach in patients with advanced cancer and to understand their decision-making process. DESIGN: Cross-sectional structured interview. SETTING: One community-based hospice and three university-based teaching hospitals. PARTICIPANTS: Two hundred thirty-four adult patients diagnosed with advanced lung, breast, prostate, or colon cancer with a life expectancy of less than 1 year: 173 hospice patients and 61 nonhospice patients receiving traditional hospital care. MEASUREMENTS: Hospice and nonhospice patients' demographic, clinical, and other patient-related characteristics were compared. Multivariate analysis was then conducted to identify variables associated with the hospice care decision in a logistic regression model. Information sources regarding hospice care and people involved in the hospice decision were identified. RESULTS: Patients receiving hospice care were significantly older (average age 69 vs 65 years, P =.009) and less educated (average 11.9 vs 12.9 years, P =.031) and had more people in their households (average 1.66 vs 1.16 persons, P =.019). Hospice patients had more comorbid conditions (1.30 vs 0.93, P =.035) and worse activities of daily living scores (7.01 vs 6.23, P =.030) than nonhospice patients. Hospice patients were more realistic about their disease course than their nonhospice counterparts. Patients' understanding of their prognoses affected their perceptions of the course of their disease. Hospice patients preferred quality of life to length of life. In the multivariate analysis, lower education level and greater number of people in the household were associated with the decision to enter hospice. A healthcare provider first told most of those who entered hospice about hospice. Families largely made the final decision to enter hospice (42%), followed by patients themselves (28%) and physicians (27%). CONCLUSION: The decision to enter hospice is related to demographic, clinical, and other patient-related characteristics. This study suggests that the decision-making process for hospice care in patients with advanced cancer is multidimensional. The healthcare community may better meet the end-of-life care needs of advanced cancer patients through enhanced communication with patients and families, including providing accurate prognoses and better understanding of patients' preferences and values.

Adult↗
PubMed2005

Conditional likelihood score functions for mixed models in linkage analysis.

In this paper, we develop a general strategy for linkage analysis, applicable for arbitrary pedigree structures and genetic models with one major gene, polygenes and shared environmental effects. Extending work of Whittemore (1996), McPeek (1999) and Hossjer (2003d), the efficient score statistic is computed from a conditional likelihood of marker data given phenotypes. The resulting semiparametric linkage analysis is very similar to nonparametric linkage based on affected individuals. The efficient score S depends not only on identical-by-descent sharing and phenotypes, but also on a few parameters chosen by the user. We focus on (1) weak penetrance models, where the major gene has a small effect and (2) rare disease models, where the major gene has a possibly strong effect but the disease causing allele is rare. We illustrate our results for a large class of genetic models with a multivariate Gaussian liability. This class incorporates one major gene, polygenes and shared environmental effects in the liability, and allows e.g. binary, Gaussian, Poisson distributed and life-length phenotypes. A detailed simulation study is conducted for Gaussian phenotypes. The performance of the two optimal score functions S(wpairs) and S(normdom) are investigated. The conclusion is that (i) inclusion of polygenic effects into the score function increases overall performance for a wide range of genetic models and (ii) score functions based on the rare disease assumption are slightly more powerful.

Alleles↗
PubMed1989

Drawbacks of selection methods for synchronous cell growth: simulation techniques.

Investigations of Koch & Schaecter's (1962) model for the fission of a bacterium were carried out to resolve some conflict in the findings due to Takahasi et al. (1968) and Marr et al. (1969). A computer simulation procedure was used to reexamine the work of Takahasi et al. Our results confirm their findings that a simple formulation of Koch & Schaecter's model predicts a synchronous growth curve which fits the data reasonably well. This contrasts with the predictions of a poor fit given by the complex formulations of Marr et al. However, there is a disagreement between our results and those obtained by Takahasi et al. It involves a relationship between independence of the life length of daughter and mother cells and the degree of synchrony in growth. The practical implications of the simulation results are that selection methods are unlikely to give perfect synchrony.

Bacteria↗
PubMed2003

Health care economic analyses.

Health care economic analyses are becoming increasingly important as health care costs consume an increasing proportion of the gross domestic product (GDP). Among the different forms of health care economic analysis are (1) cost-minimization analysis, (2) cost-benefit analysis, (3) cost-effectiveness analysis, and (4) cost-utility analysis. Cost-utility analysis is the most sophisticated because it incorporates the value (improvement in quality of life and length of life) conferred by an intervention for the resources expended. The different types of analyses of importance to the clinician are addressed herein.

Cost of Illness↗
PubMed2006

Is the quality of the patient-provider relationship associated with better adherence and health outcomes for patients with HIV?

PURPOSE: Patient-centeredness, originally defined as understanding each patient as a unique person, is widely considered the standard for high-quality interpersonal care. The purpose of our study was to examine the association between patient perception of being "known as a person" and receipt of highly active antiretroviral therapy (HAART), adherence to HAART, and health outcomes among patients with HIV. STUDY DESIGN: Cross-sectional analysis. SUBJECTS: One thousand seven hundred and forty-three patients with HIV. MEASUREMENTS: Patient reports that their HIV provider "knows me as a person" and 3 outcomes: receipt of HAART, adherence to HAART, and undetectable serum HIV RNA. RESULTS: Patients who reported that their provider knows them "as a person" were more likely to receive HAART (60% vs 47%, P<.001), be adherent to HAART (76% vs 67%, P=.007), and have undetectable serum HIV RNA (49% vs 39%, P<.001). Patients who reported their provider knows them "as a person" were also older (mean 38.0 vs 36.6 years, P<.001), reported higher quality-of-life (mean LASA score 71.1 vs 64.8, P<.001), had been followed in clinic longer (mean 64.4 vs 61.7 months, P=.008), missed fewer appointments (mean proportion missed appointments 0.124 vs 0.144, P<.001), reported more positive beliefs about HAART therapy (39% vs 28% strongly believed HIV medications could help them live longer, P<.008), reported less social stress (50% vs 62% did not eat regular meals, P<.001) and were less likely to use illicit drugs or alcohol (22% vs 33% used drugs, P<.001; 42% vs 53% used alcohol, P<.001). Controlling for patient age, sex, race/ethnicity, quality-of-life, length of time in clinic, missed appointments, health beliefs, social stress, and illicit drug and alcohol use, patients who reported their provider knows them "as a person" had higher odds of receiving HAART (odds ratio [OR] 1.41, 95% confidence interval [CI] 1.19 to 1.65), adhering to HAART (OR 1.33, 95% CI 1.02 to 1.72), and having undetectable serum HIV RNA (1.20, 95% CI 1.02 to 1.41). CONCLUSIONS: We found that a single item measuring the essence of patient-centeredness-the patients' perception of being "known as a person"-is significantly and independently associated with receiving HAART, adhering to HAART, and having undetectable serum HIV RNA. These results support the hypothesis that the quality of patient-physician relationship is directly related to the health of patients.

Adult↗
PubMed2004

Postnatal growth retardation: a universal problem in preterm infants.

BACKGROUND: Previous data from this unit suggest that postnatal growth retardation (PGR) is inevitable in preterm infants. However, the study was performed in a single level III neonatal intensive care unit and applicability of the findings to other level III or level I-II special care baby units was uncertain. OBJECTIVES: To examine postnatal hospital growth and to compare growth outcome in preterm infants discharged from four level III tertiary care units and 10 level I-II special care baby units in the former Northern Region of the United Kingdom. SUBJECTS/METHODS: Preterm infants (< or = 32 weeks gestation; < or = 1500 g) surviving to discharge were studied. Infants were weighed at birth and discharge. Body weight was converted into a z score using the British Foundation Growth Standards. To ascertain the degree of PGR, the z score at birth was subtracted from the z score at discharge. Data were evaluated using a combination of split plot (level III v I-II=main factor; individual centre=subfactor) and stepwise regression analyses. Results were considered significant at p < 0.05. RESULTS: A total of 659 (level III, n = 335; level I-II, n = 324) infants were admitted over a 24 month period (January 1998-December 1999). No differences were detected in birth characteristics, CRIB score (a measure of illness in the first 24 hours of life), length of hospital stay, weight gain, weight at discharge, or degree of PGR between infants discharged from level III and level I-II units. Significant variation was noted in length of hospital stay (approximately 35%; p < 0.001), weight gain (approximately 33%; p < 0.001), weight at discharge (approximately 20%; p < 0.001), and degree of PGR (approximately 200%; p < 0.001) between the level III units. Even greater variability was noted in the duration of hospital stay (approximately 40%; p < 0.001), weight gain (approximately 60%; p < 0.001), weight at discharge (approximately 40%, p < 0.001), and degree of PGR (approximately 300%, p < 0.001) between the level I-II units. CONCLUSIONS: These data stress the variable but universal nature of PGR in preterm infants discharged from level III and I-II neonatal intensive care units and raise important questions about nutritional support of these infants before and after hospital discharge.

Birth Weight↗
PubMedDate not supplied

The QALY model and individual preferences for health states and health profiles over time: a systematic review of the literature.

The numbers of quality-adjusted life years (QALYs) gained are increasingly being used to represent the gains in individual utility from treatment. This requires that the value of a health improvement to an individual is a simple product of gains in quality of life and length of life. The article reports on a systematic review of the literature on 2 issues: whether the value of a state is affected by how long the state lasts, and by states that come before or after it. It was found that individual preferences over health are influenced by the duration of health states and their sequence. However, although there is much variation across individual respondents, the assumptions tend to hold much better when valuations are aggregated across respondents, which is encouraging for economic evaluations that rely on using average (mean or median) values.

Empirical Research↗
PubMed2004

Changing health environment: the challenge to demonstrate cost-effectiveness of new compounds.

With the development and introduction of costly new technologies and restrictive drug budgets, health economic evaluation has gained increasing importance. Health economic evaluation is now mandatory as part of reimbursement decisions in many countries. Cost-effectiveness analysis, which relates to a defined alternative and indication, and for a specific patient group and specific perspective, is the preferred health economic analysis used to make valued judgements about the efficiency of a new treatment. The costs of the new treatment are assessed relative to its potential benefits in terms of improved health, measured as increased survival and impact on quality of life. The cost per quality-adjusted life-year (QALY), an index combining quality of life and length of life, facilitates comparisons between treatments for different diseases. Governments are increasingly using QALYas an outcome measure in economic evaluation. The QALY provides an estimate, which is then used to make a decision dependent on the willingness to pay for the treatment, based on a certain threshold value. Current thresholds, usually in the range of approximately US dollars 50000 a year (comparable with the annual cost of renal dialysis), vary between different countries. However, these thresholds are not absolute limits; choices about the allocation of healthcare resources are also influenced by other factors, including considerations of equity and the severity of the disease.

Cost-Benefit Analysis↗