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Biomedical subjects

J Hilden

Publications and source records attributed to J Hilden.

At least 37 records · Page 2Linked to original sources
PubMed2000

Comparison of ultrasound, radiography, and clinical examination in the diagnosis of acute maxillary sinusitis: a systematic review.

The objective of this study was to assess the discriminative properties of the methods for diagnosing acute maxillary sinusitis (AMS) in unselected patients. The study design was a systematic review of evaluation studies identified by using Medline, by searching reference lists, by hand searches, and by contacting investigators. Evaluation studies were conducted anywhere in the world. Subjects were adults with suspected AMS. Main outcome measures were: sensitivity, specificity, positive and negative likelihood ratios of the primary studies, weighted means of these parameters in each comparison (clinical examination, radiography, and ultrasound compared to a reference standard in diagnosing AMS), and summary ROC curves and their Q* points where sensitivity equals specificity. For the years from 1962 to present, 49 study reports were found; 11 articles on studies that included a total of 1144 patients were eligible. Compared to sinus puncture, radiography was the most accurate method for diagnosing AMS: the Q* point on the summary ROC curve was 0.82 (95% confidence interval, CI, 0.78-0.85). Ultrasound was slightly less accurate than radiography compared to sinus puncture (Q* 0.80, 95% CI 0.76-0.83). Only two articles reported clinical examination compared to sinus puncture and the Q* for them was 0.75 (95% 0.58-0.86). Clinical examination is a rather unreliable method for diagnosing AMS, even in the hands of experienced specialists. Using radiography or ultrasound improves the accuracy of diagnosis. The diagnosis of AMS is rarely studied in primary care settings. Future comparative trials should preferably combine diagnosis and treatment, evaluating the two aspects of clinical management as unit.

Acute Disease↗
PubMed2000

Phase II evaluation of interferon-alpha-2a for progressive or recurrent craniopharyngiomas.

OBJECT: Craniopharyngiomas originate from the same cells as squamous cell skin carcinoma, which can be treated successfully with interferon-alpha (IFNalpha)-2a. The authors evaluated the activity and toxicity of systemic IFN in young patients with craniopharyngiomas. METHODS: Fifteen patients between the ages of 4.2 and 19.8 years who had progressive or recurrent craniopharyngiomas were enrolled in this study. Nine of these patients had never received external-beam radiation therapy. Therapy consisted of 8,000,000 U/m2 IFNalpha-2a administered daily for 16 weeks (induction phase) followed by the same dose three times per week for an additional 32 weeks (maintenance phase). Of the 12 patients who could be evaluated, radiological studies demonstrated a response to treatment in three with predominantly cystic tumors (one minor response, one partial response, and one complete response); one of these patients also showed improvement in visual fields. The size of the cystic component of the tumors often increased temporarily during the first several months of therapy. Three patients met the criteria for progressive disease during therapy. The median time to progression was 25 months. The need for radiation therapy in patients treated with IFN was delayed for 18 to 35 months (median 25 months) in six patients. All patients developed transient flulike symptoms shortly after receiving the first dose of IFN. Other toxicities (predominantly hepatic, neurological, and cutaneous) were seen in nine (60%) of the 15 patients during the first 8 weeks of treatment but resolved after temporary discontinuation and/or dose reduction. CONCLUSIONS: Interferon-alpha-2a is active against some childhood craniopharyngiomas; its toxicity precludes administration of high daily doses, and the optimum dose level and schedule remain to be defined.

Adolescent↗
PubMed1999

[Cannabis and pregnancy].

In two Copenhagen University hospitals 12,885 pregnant women, seen during the period 1.8.1992 to 30.04.1995, answered questionnaires regarding consumption of alcohol, tobacco, cannabis and other drugs. The prevalence of cannabis use was 0.8%. Women using cannabis but no other illicit drugs were each retrospectively matched with four randomly chosen pregnant women in the same period and the same age group and with same parity. Eighty-four cannabis users were included. These women were socioeconomically disadvantaged and had a higher prevalence of present and past use of alcohol, tobacco and other drugs. No significant difference in pregnancy, delivery or puerperal outcome was found. Children of women using cannabis were 150 g lighter, 1.2 cm shorter and had 0.2 cm smaller head circumference than the control infants. Controlling for the child's sex and maternal use of alcohol did not eliminate the significant differences in birthweight and length; however, they were eliminated by controlling for maternal tobacco smoking. It is concluded, that the use of cannabis is not a major prognostic factor regarding the outcome of pregnancy, but is an indicator of low socioeconomic status and use of other substances.

Alcohol Drinking↗
PubMed1999

Analytical quality, performance indices and laboratory service.

Faulty data lead to suboptimal diagnostics and decision making unless the flaw is known and amenable to correction. However, pure noise (added analytical variance) has only minor effects on clinically appropriate indices of diagnostic performance. This fact is illustrated by an idealized screening programme, using the preventive benefit-to-cost ratio as the index of performance. Further, this article illustrates that the effect of an unnoticed source of noise is roughly just twice the effect that the same noise will have when its magnitude is known and clinical decision limits are adjusted accordingly. Owing to the small size of these effects, however, it may be profitable to spend resources on other aspects of good laboratory service, such as timeliness, documentation and interpretative support.

Clinical Laboratory Techniques↗
PubMed1999

Risk of low birthweight in social districts of Copenhagen.

The purpose of this survey was to investigate the small-area variations in low birthweight within social services districts in Copenhagen and the relation of such variations to the socioeconomic characteristics of the district. The study was based on register data and included all live-born single on births to women living in the city of Copenhagen from 1987-90. We found a statistically significant association between district and risk of newborns being small-for-gestational age (SGA). This association was independent of adjustment for maternal age and parity. Only part of the association was explained, though this was still significant, using an index summarizing the socioeconomic living conditions in the district. Splitting up the index into its four constituent components, however, showed that the association between SGA and district was primarily due to housing conditions in the districts. Mapping the districts demonstrated a clear tendency of clustering of the high-risk areas with poor socioeconomic conditions.

Cluster Analysis↗
PubMed1998

Quality adjusted survival analysis with repeated quality of life measures.

One way of examining trade-offs between quantity and quality of life (QOL) is to combine them into a single measure such as quality-adjusted life year (QALY). If censoring occurs, then estimation presents some difficulties. One approach, known as Q-TWiST, is to define a series of health states, use a 'partitioned' survival analysis to calculate the average time in each state, and then weight each state according to its quality of life to calculate QALYs. Such health-state models, however, are unhelpful when the transitions between health states are unclear or if they do not adequately reflect variations in quality of life. We therefore examine an alternative analysis to be used when repeated measures of quality of life are available from individual patients in a clinical trial. The method proceeds by separating quality of life and survival, that is, dQALY/dt = S(t)Q(t), where S(t) is the survival curve, estimated from the standard Kaplan-Meier method, and Q(t) is the quality of life function, derived from individual repeated measures of quality of life. We derive single health-state (QALY) and multiple health-state (Q-TWiST) models and illustrate the approach by comparing different durations of adjuvant chemotherapy for breast cancer.

Adult↗
PubMed1997

[Euricterus. A European database on icterus with emphasis on the Danish contribution].

Clinical and biochemical data were collected prospectively from 8032 jaundiced patients to form a database as part of a EU-supported project on computer-aided diagnosis. Patients were recruited prospectively from centres in all EU-countries and some other countries as well. Five hundred and twenty-eight jaundiced patients were collected from four centres in Denmark. Alcoholic cirrhosis, acute alcoholic liver disease and malignancy of the pancreas or the biliary tract were more common in the Danish data base: 49% of cases in Denmark as compared to 30% of cases in the international database. Viral hepatitis was underrepresented in Denmark, 16% as compared to 23% in the international group. A crude Bayesian diagnostic programme on the total database with 17 diagnostic groups achieved 63% accuracy. For the 528 Danish cases the diagnostic accuracy was 64% when the European data base was used, whereas it increased to 81% when only the Danish data base was taken as basis for the calculations. In conclusion, we found a drop in diagnostic accuracy for the Danish patients when using the large European data base instead of the national one.

Databases, Factual↗
PubMed1996

Regret graphs, diagnostic uncertainty and Youden's Index.

Regret is the difference in outcome between the action we took and the best action we could, in retrospect, have taken. 'Tent graphs', representing decision problems under uncertainty in terms of expected regret, offer an instructive geometric supplement to standard formulae, allow instant calculations, and suggest, as we shall illustrate, novel algebraic properties. For instance, the problem of finding the pre-test probability range in which it is worthwhile doing a diagnostic test becomes trivial, even when test costs depend on the unknown disease status; we take the opportunity to explore the (non-trivial) algebraic properties of this problem. The graphs also provide a simple way to illustrate and read off the expected value of information and expected value of perfect information. This property is used to derive a clinical interpretation of Youden's Index (sensitivity + specificity - 1), namely, it is the maximum proportional reduction in expected regret achieved by the test. Finally, we examine the relationship between Youden's Index and the area under an ROC curve.

Aged↗
PubMed1996

[Diagnostic imaging in suspected lumbar disk prolapse. A controlled comparison of myelography, CT and magnetic resonance imaging].

Eighty patients with monoradicular sciatica were examined by myelography, computed tomography (CT) and magnetic resonance imaging (MRI) and all had subsequent surgery. The images were evaluated by a decision-analytic regret function. The largest amount of diagnostic information was gained from CT followed by MRI and myelography. Myelography was not significantly informative. The results suggest that CT or MRI should be the first choice examination in patients with suspected lumbar disc herniation.

Adult↗
PubMed1996

The human homologue of rat NG2, a chondroitin sulfate proteoglycan, is not expressed on the cell surface of normal hematopoietic cells but is expressed by acute myeloid leukemia blasts from poor-prognosis patients with abnormalities of chromosome band 11q23.

In our efforts to produce monoclonal antibodies that recognize cell-surface antigens expressed by hematopoietic precursor and stromal cells, we generated a monoclonal antibody, 7.1, which recognizes a 220- to 240-kD cell-surface protein whose N-terminal amino acid sequence is identical to the rat NG2 chondroitin sulfate proteoglycan molecule. This chondroitin sulfate proteoglycan, previously reported to be expressed by human melanoma cells, was not found to be expressed by normal hematopoietic cells, nor was it expressed on the cell surface of cell lines of hematopoietic origin including cell lines with 11q23 abnormalities. It was found on the cell surface of acute myeloid leukemia (AML) blasts and cell lines derived from nonhematopoietic tissues. Samples of leukemic marrow from 166 children with AML enrolled on Childrens Cancer Group protocol 213 were evaluated for cell-surface expression of this proteoglycan molecule. In 18 of 166 (11%) patient samples, greater than 25% of leukemic blasts expressed the NG2 molecule. These 18 patients had a poorer outcome with respect to survival (P = .002) and event-free survival (P = .035) with an actuarial survival at 4 years of 16.7%. Blast cell expression of the NG2 molecule was strongly associated with French-American-British M5 morphology (P < .0001) and abnormalities in chromosome band 11q23, site of the MLL gene. These results show that the NG2 molecule is expressed by malignant hematopoietic cells that have abnormalities in chromosome band 11q23, suggesting that antibody 7.1 may be useful in the rapid identification of this group of poor-prognosis patients.

Actuarial Analysis↗
PubMed1996

Sociological and behavioural characteristics of perimenopausal women with an express attitude to hormone substitution therapy.

OBJECTIVES: The objective of the study is to demonstrate differences in behaviour and in sociological characteristics between women wanting hormone replacement therapy (HRT) and women refusing such treatment. METHODS: From a study base of 6189 women, 413 perimenopausal women with an express positive or negative attitude towards the use of HRT were interviewed on sociological and behavioural characteristics. Checks against bias were performed by analysis of reluctant participants, identified as women who either did not agree to participate until they received at least one reminder, or who dropped out immediately after the interview. RESULTS: Women wanting HRT had higher levels of education, were less often childless, and were more frequent solarium users than women refusing this treatment. There were no differences in marital status, employment status, the average tea, coffee, wine and cigarette consumption, sun exposure, frequencies of travels abroad, or number of family cars, summer houses or boats. No difference in present smoking status was demonstrated but the estrogen users were more frequently past or present smokers. CONCLUSIONS: It is suggested that lack of knowledge of HRT may sometimes be the cause of rejecting it, or may influence on the compliance regarding its use. Familiarity with the use of the health system for other reasons than disease may promote the use of HRT. It is demonstrated that the observed patterns do not originate from self-selection bias.

Attitude↗
PubMed1996

Computer-assisted diagnosis in gastroenterology.

During the last 20 years, Danish gastroenterologists and biostatisticians have been involved in practical and theoretical research aimed at providing computer-assisted decision support in clinical practice. On the practical side, we summarize two clinical applications, one in the acute abdomen, the other in jaundice. The former project is part of a worldwide effort which appears able to reduce considerably the perforated appendix rate and the negative laparotomy rate. In the latter project, also entwined in international activities, three methods of early statistical discrimination of jaundice causes have been tested, and it has been shown how ultrasonographic data can be incorporated into the diagnostic assessment. On the theoretical side, a Dutch-Danish group has been looking into how one best designs a trial and analyses its data in the context of measuring the quality and impact of machine-made diagnostic advice. Having pointed out the international ramifications of these activities, we outline what may lie ahead: Gastroenterologists must be prepared to join large-scale field trials of clinical advice-giving software. In the future, however, such software will often become embedded in general hospital recordkeeping systems.

Abdomen, Acute↗
PubMed1996

[Diagnosis of fibromyalgia. A critical review of the Scandinavian literature].

A critical review of Nordic literature on fibromyalgia (FMA), undertaken to test the hypothesised inadequacy of the diagnosis, shows the diagnostic criteria to be entirely subjective and arbitrary, and their use to give rise to problems even in controlled studies. Studies have not only shown even small differences in the diagnostic criteria to have profound impact on prevalence figures and to produce apparent fluctuations on the patient population, but also that the prevalence is higher in areas where many cases have already been diagnosed. No common aetiology or pathogenetic mechanism can be identified, and the massive overrepresentation of women remains unexplained. The patient group is characterised by heterogeneity, and no treatment has shown to be specifically beneficial. Papers offering alternative explanations of FMA are concerned with the reasons why FMA is diagnosed, rather than its cause.

Analgesia↗