Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “missing data”

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 343 records · Page 19Linked to original sources
PubMed2001

Castor oil, bath and/or enema for cervical priming and induction of labour.

BACKGROUND: Castor oil, a potent cathartic, is derived from the bean of the castor plant. Anecdotal reports, which date back to ancient Egypt have suggested the use of castor oil to stimulate labour. Castor oil has been widely used as a traditional method of initiating labour in midwifery practice. Its role in the initiation of labour is poorly understood and data examining its efficacy within a clinical trial are limited. This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology. OBJECTIVES: To determine the effects of castor oil or enemas for third trimester cervical ripening or induction of labour in comparison with other methods of cervical ripening or induction of labour. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register and bibliographies of relevant papers. Last searched: November 2000. SELECTION CRITERIA: (1) clinical trials comparing castor oil, bath or enemas used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions. DATA COLLECTION AND ANALYSIS: A strategy has been developed to deal with the large volume and complexity of trial data relating to labour induction. This involves a two-stage method of data extraction. MAIN RESULTS: In the one included study of 100 women, which compared a single dose of castor oil versus no treatment, no difference was found between caesarean section rates (relative risk (RR) 2.31, 95% CI 0.77, 6.87). No data were presented on neonatal or maternal mortality or morbidity. There was no difference between either the rate of meconium stained liquor (RR 0.77, 95% CI 0.25,2.36) or Apgar score < 7 at 5 minutes (RR 0.92, 95% CI 0.02,45.71) between the two groups. The number of participants was small hence only large differences in outcomes could have been detected. All women who ingested castor oil felt nauseous. REVIEWER'S CONCLUSIONS: The only trial included in this review attempts to address the role of castor oil as an induction agent. The trial was small and of poor methodological quality. Further research is needed to attempt to quantify the efficacy of castor oil as an induction agent.

Castor Oil↗
PubMed2001

Corticosteroids for induction of labour.

BACKGROUND: The role of corticosteroids in the process of labour is not well understood. Animal studies have shown the importance of cortisol secretion by the fetal adrenal gland in initiating labour in sheep. Infusion of glucocorticosteroids into the fetus has also shown to induce premature labour in sheep. Some assumptions have been proposed regarding the mode of action of corticosteroids, including both a paracrine and autocrine action, following the identification of glucocorticoid receptors on human amnion. Given these studies it has been postulated that corticosteroids given intraamniotically will promote the induction of labour. This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology. OBJECTIVES: To determine the effects of corticosteroids for third trimester cervical ripening or induction of labour in comparison with other methods of cervical priming or induction of labour. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register and bibliographies of relevant papers. Last searched: November 2000. SELECTION CRITERIA: (1) clinical trials comparing corticosteroids used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions. DATA COLLECTION AND ANALYSIS: A strategy has been developed to deal with the large volume and complexity of trial data relating to labour induction. This involves a two-stage method of data extraction. MAIN RESULTS: There are no included trials, hence no results are presented. REVIEWER'S CONCLUSIONS: The effectiveness of corticosteroids for induction of labour is uncertain. Use of this method of induction of labour is not commonly used and further research in this area is probably unwarranted.

Administration, Topical↗
PubMed2001

Vaginal prostaglandin (PGE2 and PGF2a) for induction of labour at term.

BACKGROUND: Prostaglandins have been used for induction of labour since the 1960s. Initial work focused on prostaglandin F2a as prostaglandin E2 was considered unsuitable for a number of reasons. With the development of alternative routes of administration, comparisons were made between various formulations of vaginal prostaglandins. This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology. OBJECTIVES: To determine the effects of vaginal prostaglandins E2 and F2a for third trimester cervical ripening or induction of labour in comparison with placebo/no treatment or other vaginal prostaglandins (except Misoprostol). SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled trials register and bibliographies of relevant papers. Last searched: November 2000. SELECTION CRITERIA: The criteria for inclusion included the following: (1) clinical trials comparing vaginal prostaglandins used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions. DATA COLLECTION AND ANALYSIS: A strategy has been developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction. The initial data extraction was done centrally, and incorporated into a series of primary reviews arranged by methods of induction of labour, following a standardised methodology. The data was then extracted from the primary reviews into a series of secondary reviews, arranged by category of woman. To avoid duplication of data in the primary reviews, the labour induction methods were listed in a specific order, from one to 23. Each primary review included comparisons between one of the methods (from two to 23) with only those methods above it on the list. MAIN RESULTS: In total, 94 studies were considered; 42 have been excluded and 52 included examining a total of 9402 women. Vaginal prostaglandin E2 compared with placebo or no treatment reduced the likelihood of vaginal delivery not being achieved within 24 hours (18% vs. 99%, RR 0.19, 95% CI 0.14,0.25), the caesarean section rates were not different between groups although the risk of uterine hyperstimulation with fetal heart rate changes was increased (4.6% vs. 0.51%, RR 4.14, 95% CI 1.93, 8.90). Comparison of vaginal prostaglandin F2a with placebo showed no increase in caesarean section rates but the cervical score was more likely to be improved (15% vs. 60%, RR 0.25, 95% CI 0.13,0.49), and the risk of oxytocin augmentation reduced (53.9% vs. 89.1%, RR 0.60, 95% CI 0.43,0.84) with the use of vaginal PGF2a. There were insufficient data to make meaningful conclusions for the comparison of vaginal PGE2 and PGF2a. PGE2 tablet, gel and pessary appear to be as efficacious as each other. Lower dose regimes, as defined in the review, appear as efficacious as higher dose regimes. REVIEWER'S CONCLUSIONS: The primary aim of this review was to examine the efficacy of vaginal prostaglandin E2 and F2a. This is reflected by an increase in successful vaginal delivery rates in 24 hours, no increase in operative delivery rates and significant improvements in cervical favourability within 24-48 hours. Further research is needed to quantify the cost-analysis of induction of labour with vaginal prostaglandins, with special attention to different methods of administration.

Administration, Intravaginal↗
PubMed2001

Relaxin for cervical ripening and induction of labour.

BACKGROUND: Relaxin is a protein hormone composed of two amino acid chains. The role played by relaxin in human pregnancy and parturition is unclear. Its use and involvement as a cervical ripening agent has been debated since the 1950s. Because the main source of human relaxin is the corpus luteum of pregnancy much of the early work on induction of labour has focused on porcine or bovine preparations. With the advent of DNA recombinant technology human relaxin has become available for evaluation. Relaxin is thought to have a promoting effect on cervical ripening. Due to a possible inhibitory effect on human myometrial activity, relaxin may not be associated with the concomitant increase in the rate of uterine hyperstimulation seen with other induction agents. This is one of a series of reviews of methods of cervical ripening and labour induction using a standardised methodology. OBJECTIVES: To determine the effects of relaxin (both purified porcine and recombinant human) for third trimester cervical ripening or induction of labour in comparison with other methods of induction. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled trials register and bibliographies of relevant papers. Last searched: November 2000. SELECTION CRITERIA: (1) clinical trials comparing relaxin used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusion. DATA COLLECTION AND ANALYSIS: A strategy has been developed to deal with the large volume and complexity of trial data relating to labour induction. This involves a two-stage method of data extraction. MAIN RESULTS: In total, nine studies were considered; five have been excluded and four included examining a total of 267 women. There were no reported cases of uterine hyperstimulation with fetal heart rate changes in any of the studies. The rate of caesarean section was not different in those women given relaxin compared with placebo (15.3% versus 14.2%; relative risk (RR) 0.79, 95% confidence interval (CI) 0.42,1.50). There was a reduction in the risk of the cervix remaining unfavourable or unchanged with induction with relaxin (21.9% versus 49.3%; RR 0.45, 95% CI 0.28,0.72). There were no reported cases of uterine hyperstimulation without FHR changes. REVIEWER'S CONCLUSIONS: The place of relaxin, either purified porcine or recombinant human, as an induction or cervical priming agent is unclear. Further trials are needed to estimate the true effect of relaxin within current clinical practice.

Animals↗
PubMed2001

Intravenous oxytocin alone for cervical ripening and induction of labour.

BACKGROUND: Oxytocin is the commonest induction agent used worldwide. It has been used alone, in combination with amniotomy or following cervical ripening with other pharmacological or non-pharmacological methods. Prior to the introduction of prostaglandin agents oxytocin was used as a cervical ripening agent as well. In developed countries oxytocin alone is more commonly used in the presence of ruptured membranes whether spontaneous or artificial. In developing countries where the incidence of HIV is high, delaying amniotomy in labour reduces vertical transmission rates and hence the use of oxytocin with intact membranes warrants further investigation. This review will address the use of oxytocin alone for induction of labour. Amniotomy alone or oxytocin with amniotomy for induction of labour has been reviewed elsewhere in the Cochrane Library. Trials which consider concomitant administration of oxytocin and amniotomy will not be considered. This is one of a series of reviews of methods of cervical ripening and labour induction using a standardised methodology. OBJECTIVES: To determine the effects of oxytocin alone for third trimester cervical ripening or induction of labour in comparison with other methods of induction of labour or placebo/no treatment. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group Trials Register, the Cochrane Controlled Trials Register and bibliographies of relevant papers. Last searched: May 2001. SELECTION CRITERIA: The criteria for inclusion included the following: (1) clinical trials comparing vaginal prostaglandins used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions. DATA COLLECTION AND ANALYSIS: A strategy was developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction. The initial data extraction was done centrally, and incorporated into a series of primary reviews arranged by methods of induction of labour, following a standardised methodology. The data is to be extracted from the primary reviews into a series of secondary reviews, arranged by category of woman. MAIN RESULTS: In total, 110 trials were considered; 52 have been excluded and 58 included examining a total of 11,129 women. Comparing oxytocin alone with expectant management: Oxytocin alone reduced the rate of unsuccessful vaginal delivery within 24 hours when compared with expectant management (8.3% versus 54%, relative risk (RR) 0.16, 95% confidence interval (CI) 0.10,0.25) but the caesarean section rate was increased (10.4% versus 8.9%, RR 1.17, 95% CI 1.01,1.36). This increase in caesarean section rate was not apparent in the subgroup analyses. Women were less likely to be unsatisfied with induction rather than expectant management, in the one trial reporting this outcome (5.5% versus 13.7%, RR 0.43, 95% CI 0.33, 0.56). Comparing oxytocin alone with vaginal prostaglandins: Oxytocin alone was associated with an increase in unsuccessful vaginal delivery within 24 hours (52% versus 28%, RR 1.85, 95% CI 1.41, 2.43), irrespective of membrane status, but there was no difference in caesarean section rates (11.4% versus 10%, RR 1.12, 95% CI 0.95, 1.33). Comparing oxytocin alone with intracervical prostaglandins: Oxytocin alone was associated with an increase in unsuccessful vaginal delivery within 24 hours when compared with intracervical PGE2 (51% versus 35%, RR 1.49, 95% CI 1.12,1.99). For all women with an unfavourable cervix regardless of membrane status, the caesarean section rates were increased (19.0% versus 13.1%, RR 1.42, 95% CI 1.11, 1.82). REVIEWER'S CONCLUSIONS: Overall, comparison of oxytocin alone with either intravaginal or intracervical PGE2 reveals that the prostaglandin agents probably overall have more benefits than oxytocin alone. The amount of information relating to specific clinical subgroups is limited, especially with respect to women with intact membranes. Comparison of oxytocin alone to vaginal PGE2 in women with ruptured membranes reveals that both interventions are probably equally efficacious with each having some advantages and disadvantages over the others. With respect to current practice in women with ruptured membranes induction can be recommended by either method and in women with intact membranes there is insufficient information to make firm recommendations.

Cervical Ripening↗
PubMed2001

Amniotomy plus intravenous oxytocin for induction of labour.

BACKGROUND: Induction of labour is a common obstetric intervention. Amniotomy alone for induction of labour is reviewed separately and oxytocin alone for induction of labour is being prepared for inclusion in The Cochrane Library. This review will address the use of the combination of these two methods for induction of labour in the third trimester. This is one of a series of reviews of methods of cervical ripening and labour induction using standardised methodology. OBJECTIVES: To determine, from the best available evidence, the efficacy and safety of amniotomy and intravenous oxytocin for third trimester induction of labour. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group Trials Register, the Cochrane Controlled Trials Register and reference lists of articles were searched. Date of last search: May 2001. SELECTION CRITERIA: The criteria for inclusion included the following: (1) clinical trials comparing amniotomy plus intravenous oxytocin used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions. DATA COLLECTION AND ANALYSIS: Trial quality assessment and data extraction were done by both reviewers. A strategy was developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction. The initial data extraction was done centrally, and incorporated into a series of primary reviews arranged by methods of induction of labour, following a standardised methodology. The data is to be extracted from the primary reviews into a series of secondary reviews, arranged by category of woman. MAIN RESULTS: Seventeen trials involving 2566 women were included. Amniotomy and intravenous oxytocin were found to result in fewer women being undelivered vaginally at 24 hours than amniotomy alone (relative risk (RR) 0.03, 95% confidence intervals (CI) 0.001-0.49). This finding was based on the results of a single study of 100 women. As regards secondary results amniotomy and intravenous oxytocin resulted in significantly fewer instrumental vaginal deliveries than placebo (RR 0.18, CI 0.05-0.58). Amniotomy and intravenous oxytocin resulted in more postpartum haemorrhage than vaginal prostaglandins (RR 5.5, CI 1.26-24.07). Significantly more women were also dissatisfied with amniotomy and intravenous oxytocin when compared with vaginal prostaglandins, RR 53, CI 3.32-846.51. REVIEWER'S CONCLUSIONS: Data on the effectiveness and safety of amniotomy and intravenous oxytocin are lacking. No recommendations for clinical practice can be made on the basis of this review. Amniotomy and intravenous oxytocin is a combination of two methods of induction of labour and both methods are utilised in clinical practice. If their use is to be continued it is important to compare the effectiveness and safety of these methods, and to define under which clinical circumstances one may be preferable to another.

Amnion↗
PubMed2001

Breast stimulation for cervical ripening and induction of labour.

BACKGROUND: Breast stimulation has been suggested as an effective means of inducing labour. It is both an inexpensive and non-medical intervention which allows women greater control over the induction process. It is not clear how breast stimulation increases uterine contractions, however it has been shown to be effective for contraction stress tests and for the augmentation of labour. This is one of a series of reviews of methods of cervical ripening and labour induction using a standardised methodology. OBJECTIVES: To determine the effectiveness of breast stimulation for third trimester cervical ripening or induction of labour in comparison with placebo/no intervention or other methods of induction of labour. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register and bibliographies of relevant papers. Last searched: April 2001. SELECTION CRITERIA: (1) randomised controlled trials comparing breast stimulation used for third trimester cervical ripening or labour induction with no intervention or other methods listed above it on a predefined list of labour induction methods; (2) random allocation to the treatment or the control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaning outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions. DATA COLLECTION AND ANALYSIS: A generic strategy has been developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction. The initial data extraction was done centrally. MAIN RESULTS: Six randomised controlled trials were included in the analysis involving 719 women. When trials comparing breast stimulation with no intervention were analysed there was a significant reduction in the number of women not in labour at 72 hours (62.7% versus 93.6%, relative risk (RR) 0.67, 95% confidence interval (CI) 0.60 - 0.74). However, this result did not remain significant in women with an unfavourable cervix. There were no instances of uterine hyperstimulation. A reduction in the rate of postpartum haemorrhage was reported (0.7% versus 6%, RR 0.16, 95% CI 0.03 - 0.87). No significant difference was detected in the caesarean section rate (9% versus 10%, relative risk RR 0.90, 95% CI 0.38 - 2.12) or rates of meconium staining. Three perinatal deaths were reported (1.8% versus 0%, RR 8.17, 95% CI 0.45 - 147.77). This finding should be interpreted with caution. The three deaths occurred in the breast stimulation arm of a three-armed trial (breast stimulation versus no intervention versus oxytocin) of questionable quality. The study was very small (n = 57), involved only high risk women, and the method of randomisation was not reported. When comparing breast stimulation with oxytocin alone the analysis found no difference in caesarean section rates (28% versus 47%, RR 0.60, 95% CI 0.31 - 1.18). No difference was detected in the number of women not in labour after 72 hours (58.8% versus 25%, RR 2.35, 95% CI 1.00 - 5.54). There was no significant difference in the rates of meconium staining. There were four perinatal deaths. Three in the breast stimulation arm, and one in the oxytocin arm of the three-armed trial noted above (17.6% versus 5%, RR 3.53, 95% CI 0.40-30.88). REVIEWER'S CONCLUSIONS: Breast stimulation cannot be fully evaluated on efficacy and safety grounds from the included studies. Whilst it would appear beneficial in terms of a reduction in the number of women not in labour after 72 hours, and a reduction in postpartum haemorrhage, until safety issues have been fully evaluated it should not be considered for use in a high risk population.

Breast↗
PubMed2001

Oestrogens alone or with amniotomy for cervical ripening or induction of labour.

BACKGROUND: Studies in sheep showed that there is a pre-labour rise in oestrogen and a decrease in progesterone, both of these changes stimulate prostaglandin production and may help initiate labour. Though oestrogen has been suggested as an effective cervical ripening or induction agent, research in humans have failed to demonstrate a similar physiological mechanism. The use of oestrogen as an induction agent is not currently common practice, as such this systematic review should be regarded as an historical review. This is one of a series of reviews of methods of cervical ripening and labour induction using a standardised methodology. OBJECTIVES: To determine, from the best available evidence, the effectiveness and safety of oestrogens alone or with amniotomy for third trimester cervical ripening and induction of labour in comparison with other methods of induction of labour. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register and bibliographies of relevant papers. Last searched: April 2001. SELECTION CRITERIA: (1) randomised controlled trials comparing oestrogens alone used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed above it on a predefined list of labour induction methods; (2) random allocation to the treatment or control group; (3) adequate allocation concealment; (4) violations of allocated management not sufficient to materially affect conclusions; (5) clinically meaningful outcome measures reported; (6) data available for analysis according to the random allocation; (7) missing data insufficient to materially affect the conclusions. DATA COLLECTION AND ANALYSIS: A generic strategy has been developed to deal with the large volume and complexity of trial data relating to labour induction. This involved a two-stage method of data extraction. The initial data extraction was done centrally. MAIN RESULTS: When comparing oestrogen with placebo there was no difference between the rate of caesarean section (7.1% versus 10.3%, relative risk (RR) 0.70, 95% confidence interval (CI) 0.30,1.62). There were no differences between rates of uterine hyperstimulation with or without fetal heart rate changes or instrumental vaginal delivery. None of the studies reported the rates of either vaginal delivery not achieved in 24 hours, or cervix unfavourable/unchanged after 12-24 hours. There were insufficient data to make any meaningful conclusions when comparing oestrogen with vaginal PGE2, intracervical PGE2, oxytocin alone or extra amniotic PGF2a, as to whether oestrogen is effective in inducing labour. REVIEWER'S CONCLUSIONS: There were insufficient data to draw any conclusions regarding the efficacy of oestrogen as an induction agent.

Amnion↗
PubMed1997

Individual subject random assignment is the preferred means of evaluating behavioral lifestyle modification.

Of the three most important approaches to evaluating lifestyle and health outcomes--observational studies, individual subject random assignment clinical trials, and community random assignment clinical trials--individual subject random assignment clinical trials provide the most useful information and the most certain inferences. Observational studies are limited by the collection of information on association of lifestyle instead of change in lifestyle with health outcomes, as well as by individual lifestyle selection that may be associated with particular outcomes. Community randomized trials may be the best way to decide such public health policy issues as whether or not to add fluoride to a water supply or to use a community-wide anti-smoking program. The limited amount of individual-specific data collected in community randomized trials, difficulties in accounting for missing data, and problems in data analysis because people move into or out of communities that are under study limit the value of community randomized trials for advising individuals whether or not to embark on a lifestyle modification program. Clinical trials of pharmacologic agents have successfully addressed challenges to individual subject random assignment clinical trials of lifestyle modification, such as long duration of study, access to study intervention(s) by individuals not assigned them, and cost.

Community Health Services↗
PubMed1989

Nicardipine and propranolol in the treatment of essential hypertension.

Two hundred thirty-four patients with supine diastolic blood pressure of between 95 and 114 mm Hg were enrolled into a double-blind, randomized, parallel, multicenter trial. The patients were randomized to either nicardipine 30 mg tid, propranolol 40 mg tid, or nicardipine 30 mg tid and propranolol 40 mg tid for six weeks. Two hundred six patients yielded data for analyses. Of the 28 not included, seven had missing data, whereas the remaining 21 were excluded because they either failed to meet inclusion criteria or were noncompliant at endpoint. Both nicardipine and propranolol as monotherapies and in combination achieved statistically significant, (P less than .01), supine diastolic blood pressure reduction relative to baseline. The combination of nicardipine and propranolol showed a greater reduction in supine diastolic and systolic measurements than either of the monotherapies. Nicardipine produced greater blood pressure reductions one hour after dosing, whereas the propranolol treatment tended to produce slightly greater blood pressure decreases eight hours after dose. The combination always resulted in the greatest blood pressure reduction, independent of time after dose. Adverse experiences were reported by 26% of patients in the nicardipine-treated group, most often transient vasodilatory effects, by 17% of the propranolol-treated patients, and by 18% of the combination-treated group. This study demonstrated at the doses studied that nicardipine alone produced equivalent blood pressure reductions to those obtained by propranolol alone, but that the combination of these two drugs produced greater reductions in blood pressures than either of the monotherapies.

Adult↗
PubMed1998

Molecular phylogeny of the genus Hypochaeris using internal transcribed spacers of nuclear rDNA: inference for chromosomal evolution.

Sequences of the internal transcribed spacers (ITSs) of 18S-26S nuclear ribosomal DNA were used to resolve phylogenetic relationships and chromosomal evolution among 14 species of the genus Hypochaeris (Asteraceae). Parsimony analysis was performed for phylogenetic reconstruction, and sequence divergence between species was estimated. Pairwise sequence divergence within Hypochaeris genus ranged from 0% to 25.68% in ITS1 and from 0% to 17.08% in ITS2. A highly resolved strict-consensus tree was obtained that showed the phylogenetically useful information of ITS sequences within the genus Hypochaeris. Four clades could be well distinguished, one of them formed by the single species H. robertia, which appeared to be the most related to the ancestral species of the genus. The results agree with taxonomic classification based on morphological data, and the tree obtained, when indels are coded as missing data, aggregates the species having the same chromosome number, except in one clade. According to the ITS phylogenetic tree, the chromosomal evolution within the genus Hypochaeris conflicts with the previous hypothesis and suggests that karyotype evolution in Hypochaeris was accompanied with both decreasing and increasing dysploidy, probably with several chromosomal rearrangements, and from an ancestral basic chromosome number of 4 or 5.

Asteraceae↗
PubMed1995

The feasibility and cost of a large multicentre audit of process and outcome of prostatectomy.

Objective--To determine the feasibility of performing multicentre process and outcome audits of common interventions taking prostatic procedures as an example. Design--Prospective, cohort study. Setting--All National Health Service and independent hospitals in Northern, Wessex, Mersey, and South West Thames health regions. Patients--5361 men undergoing prostatectomy identified by 103 of the 107 urologists and general surgeons performing prostatectomy in the study regions. Main measures-- Rates of participation by surgeons and patients; completeness of clinical data provided by surgeons; patient response rate and completeness of patient derived data; and cost. Results--Most surgeons (103,96%) agreed to participate. Overall, the proportion of eligible patients invited to take part was high (89%), although this was only measured in South West Thames, where dedicated data collectors were employed. Few men (80, 1.5%) declined to participate. Of those surviving for three months after surgery, 82.4% (4226) completed and returned the postal questionnaire. The response rate was higher in South West Thames (86.7%) than in the other regions (80.6%-80.8%). The audit was well received: 91% of patients found the questionnaire easy to complete and only 2.3% of them disapproved. Completeness of data was high with both the hospital and patient questionnaires. Missing data occurred in less than 5% of responses to most questions. The attributable cost was 34.50 pounds per patient identified or 44 pounds for patients in whom either the treatment outcome or vital status was known three months after their prostatectomy. Conclusions--This multicentre audit of process and outcome of prostatectomy proved feasible in terms of surgeon participation, patient identification, and the quantity and quality of data collection. Whether the cost was warranted will depend on how surgeons use the audit data to modify their practice.

Aged↗
PubMed1997

Now you see it, now you don't: a comparison of traditional versus random-effects regression models in the analysis of longitudinal follow-up data from a clinical trial.

To illustrate the limitations of commonly used methods of handling missing data when using traditional analysis of variance (ANOVA) models and highlight the relative advantages of random-effects regression models, multiple analytic strategies were applied to follow-up data from a clinical trial. Traditional ANOVA and random-effects models produced similar results when underlying assumptions were met and data were complete. However, analyses based on subsamples, to which investigators would have been limited with traditional models, would have led to different conclusions about treatment effects over time than analyses based on intention-to-treat samples using random-effects regression models. These findings underscore the advantages of models that use all data collected and the importance of complete data collection to minimize sample bias.

Adult↗
PubMed1998

Magnetic resonance imaging for the investigation of knee injuries: an investigation of preferences.

The conventional approach to the diagnosis and treatment of severe knee injuries is arthroscopy, a minimally invasive surgical procedure. Since arthroscopy is an invasive technique that carries risks, magnetic resonance imaging (MRI) is increasingly being used for diagnosis. MRI is potentially associated with diagnostic and therapeutic 'impacts', in that arthroscopy can be avoided. This paper reports a discrete choice conjoint analysis exercise that assessed the value placed on such 'impacts' by potential patients and investigated the degree to which respondents were willing to trade between process and outcome. The marginal rates of substitution between attributes were estimated. The results suggest that the diagnostic and therapeutic 'impacts' of MRI were valued by many respondents. The study has highlighted a number of important issues for the design and analysis of future health-related conjoint studies, including the use of treatment cost as an attribute, dealing with data from lexicographic respondents, and distinguishing between points of indifference and missing data.

Adult↗
PubMedDate not supplied

"Keyhole" method for accelerating imaging of contrast agent uptake.

Magnetic resonance (MR) imaging methods with good spatial and contrast resolution are often too slow to follow the uptake of contrast agents with the desired temporal resolution. Imaging can be accelerated by skipping the acquisition of data normally taken with strong phase-encoding gradients, restricting acquisition to weak-gradient data only. If the usual procedure of substituting zeroes for the missing data is followed, blurring results. Substituting instead reference data taken before or well after contrast agent injection reduces this problem. Volunteer and patient images obtained by using such reference data show that imaging can be usefully accelerated severalfold. Cortical and medullary regions of interest and whole kidney regions were studied, and both gradient- and spin-echo images are shown. The method is believed to be compatible with other acceleration methods such as half-Fourier reconstruction and reading of more than one line of k space per excitation.

Contrast Media↗
PubMed1994

Crossover designs for clinical trials.

I discuss three-period crossover designs for an efficient comparison of two test treatments with special application to clinical trials which often have many practical limitations. In this paper I specify a subset of three-period crossover designs so that the investigators are not left with the problematic two-period two-sequence design, should the trials be terminated after the second period. I show that there is a dramatic reduction in variability for estimating the direct and residual treatment effects in three-period designs compared to two-period designs. I also show that the universally optimal design with ABB and BAA sequences is unsuitable when a complex form of residual effects is suspected, such as the second-order residual effects or treatment by period interactions. The design with ABB, BAA, AAB, and BBA sequences is relatively robust to these uncertain model assumptions. I also discuss missing data problems and conclude that, even with a large proportion of missing values, the three-period design is far more efficient than the two-period design.

Analysis of Variance↗
PubMed1994

A PC program for classification into one of several groups on the basis of longitudinal data.

A stand-alone, menu-driven PC program, ZCLASS, written in GAUSS386i, for classifying subjects into one of several distinct, existing groups on the basis of longitudinal data is described, illustrated, and made available to interested readers. The program accepts data from studies where common times of measurement are planned, but missing data are accommodated in that one or more measurement sequences may be incomplete.

Anthropometry↗
PubMed1988

Microcomputer application of Bayesean probability testing for the identification of bacteria.

A computer program (BACTID) is described which facilitates the identification of bacteria based on a priori data and Bayesean probability testing. The program is not limited to a specific format, has a short execution time, can be easily applied to a variety of situations, and can be run on almost any microcomputer system operating under either 8-bit CP/M or 16-bit MS-DOS/PC-DOS. Additionally, BACTID (1) is not limited to one type of computer (hardware independent), (2) is not limited by size of the computer's random access (RAM independent), (3) can recognize various data bases matrices (format independent), (4) is able to compensate for missing data and (5) allows for various methods of data entry. The efficacy of the program was checked against a commercially available test system and a 99.34% agreement was obtained. Also, the execution time for a 46 x 21 element data matrix was as little as 3.5 s. These results show that microcomputer identification programs are not only viable alternatives to code book registers, but also offer flexibility which is not found in commercial systems.

Bacteria↗