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PubMed2002

Myocardial infarction and third generation oral contraceptives: aggregation of recent studies.

BACKGROUND: Arterial cardiovascular and cerebrovascular adverse events associated with oral contraceptives (OC) are a major concern to the clinician. This paper aggregates the findings of seven recent oral contraceptive studies on the risk of acute myocardial infarction (MI) among users of second (2gen) and third (3gen) generation OC. METHODS: Odds ratios (OR) from seven original studies published between 1996 and 2001 underwent meta-analysis. They had accrued 6464 subjects since 1996. In addition, estimates of 22 studies published from 1965 to 1966 were synthesized using medians and ranges as an historical point of reference. RESULTS: Four meta-analyses were performed for each of the relevant comparisons. The point estimates for 3gen versus 2gen OC ranged from 0.44 (0.24-0.80) to 0.62 (0.38-0.99). Compared with non-users, the aggregated OR for 3gen OC was 1.13 (0.66-1.92); for 2gen OC it was 2.18 (1.62-2.94). CONCLUSIONS: This overview of seven controlled observational studies confirms that 3gen OC do not convey harm in regard to MI compared with non-users of OC. The aggregate data and the continuing replication of findings allow interpretation of benefit compared with older combined OC.

Contraceptives, Oral↗

PubMed1995

Ways of seeing: explaining variations in use of acute hospital services.

BACKGROUND: In the US Medicare programme, hospitals are paid directly by activity. To provide incentives for efficiency, the US Federal Government has sought objective measures of inpatients' need for resources. In the UK National Health Service, resources are allocated for acute hospital services as part of a global budget to purchasers, who then contract with hospitals. To provide equity in resource allocation, the Department of Health in England, has sought objective measures of populations' need for resources. METHODS: Examination of policy and technology that has used variations in utilization of resources to derive objective measures of efficiency and equity. RESULTS: The technology of developing empirical measures of resources needed by patients has lacked information on outcomes, which is vital for measures of efficiency. The technology of developing empirical measures of resources needed by populations has relied on aggregate data. Analyses of specific procedures and conditions consistently find that these variations are explained by differences in medical practice and not by need. CONCLUSIONS: There is scope for multidisciplinary research to explain small area variations for specific procedures and conditions in resources used by populations. It seems unlikely, however, that governments will be interested in findings from this research.

Health Care Rationing↗

PubMed1999

European stillbirth proportions before and after the Chernobyl accident.

BACKGROUND: Numerous investigations have been carried out concerning the possible impact of the Chernobyl accident, in April 1986, on the prevalence of anomalies at birth and on perinatal mortality. The accident has contaminated Eastern Europe more heavily than Western Europe. If there was an effect of the radioactive contamination on perinatal mortality or stillbirth proportions one would expect to find it more pronounced in Eastern Europe as compared to Western Europe. We therefore studied long-term time trends in European stillbirth proportions. METHODS: Linear logistic regression was applied to model the time trends in stillbirth proportions. Dummy variables were used to account for effects that can be associated with certain years or locations. A synoptic logistic regression model is suggested for the western, central, and eastern parts of Europe. RESULTS: There is a marked differential effect in the long-term stillbirth time trends between Western Europe (Belgium, France, Great Britain, Iceland, Ireland, Luxembourg, Portugal, Spain), Central Europe (Austria, Denmark, Germany, Italy, Norway, Switzerland), and Eastern Europe represented by four countries (Greece, Hungary, Poland, Sweden). In contrast to the western and central European trends, the eastern European trend exhibits an absolute increase of the stillbirth proportion in 1986 as compared with 1985 and an apparent upward shift of the whole trend line from 1986 on. CONCLUSION: Our results are in contrast to those of many analyses of the health consequences of the Chernobyl accident and contradict the present radiobiological knowledge. As we are dealing with highly aggregated data, other causes or artefacts may explain the observed effects. Hence, the findings should be interpreted with caution and further independent evidence should be sought.

Europe↗

PubMed1999

Physician attitudes, self-estimated performance and actual compliance with locally peer-defined quality evaluation criteria.

BACKGROUND: Physicians' agreement with quality evaluation criteria, and estimates of their own and their colleagues' compliance with these criteria were compared with actual compliance. METHODS: Physicians practicing in 10 health centers in Spain defined 13 quality evaluation criteria for two patient conditions (upper respiratory infections and high serum cholesterol). Compliance with criteria was measured by an external team, using random samples of medical records stratified by condition in each health center (n= 1,000). Concurrently, physicians were surveyed regarding agreement with the criteria, and were asked to estimate their own and their health center's rate of compliance with these criteria. RESULTS: Agreement ratings varied from 5.9 to 9.1 on a 10-point scale. Actual compliance rates ranged from 1.8 to 91.7% of records. Agreement correlated significantly with self-reported compliance but not with actual compliance. Estimates of one's own and one's health center compliance were positive and significantly correlated for all criteria, but were significantly higher for oneself than for one's health center for six of 13 criteria. CONCLUSIONS: Wide variation in physicians' agreement on quality criteria and in actual performance reveal a lack of clear guidelines. Agreement on criteria did not always translate into compliance with criteria. Physicians tended to rate their own performance as better than the average of their peers, suggesting that aggregate data may not influence physicians to change. Self-estimate of one's own or one's colleagues performance is not a good proxy for actual performance so that peer ratings are of dubious value for performance appraisal.

Attitude of Health Personnel↗

PubMed2004

Individual patient-level and study-level meta-analysis for investigating modifiers of treatment effect.

BACKGROUND: In meta-analyses of clinical trials, clinicians are often interested in examining subset effects. Meta-regression of aggregated data is a usual approach for relating sources of variation in treatment effects to specific study characteristics. However, it is known that study-level analyses can lead to biased assessments and have some limitations in explaining the heterogeneity. An individual patient data (IPD) meta-analysis offers several advantages for this purpose. METHODS: We compared some regression analyses of IPD with meta-regression analyses of the summarized data using a real-world example in order to investigate whether a binary patient characteristic is related to treatment effect. We used data from 10 randomized trials for non-small-cell lung cancer (n = 1355). RESULTS: For treatment x stage interaction in IPD regression analysis, none of the tests of interactions was statistically significant. The meta-regression analysis gave a greater P-value than the IPD analysis. When excluding two studies, which had only stage I patients, the interaction was also not statistically significant in IPD analysis. On the other hand, the result of meta-regression analysis, though also showing no significant relationship, revealed a clear reversal in the direction of effect. CONCLUSION: We suggest that the results of meta-regression analyses would not be as robust as those of regression analyses using IPD in examining potential modifiers of treatment effects. To investigate whether patient characteristics are related to treatment effects, we suggest that interaction tests and sensitivity analyses using IPD should be employed whenever possible.

Carcinoma, Non-Small-Cell Lung↗

PubMed1990

In-home nutritional assessment of inner-city elderly.

Aims of this research have been to obtain aggregate data on reported problems in food access that are experienced by homebound, inner-city elderly; to disaggregate the data to show which subgroups of elderly are at highest risk for these types of food insecurity; and to assess whether these elderly differ socioeconomically, medically, or nutritionally from homebound elderly who report that they eat regularly. Instruments were designed to measure population-based food insecurity and to ask respondents to provide information about their socioeconomic status and disabilities as well as the extent to which they have formal or informal assistance in obtaining food. The need to collect this information has been linked to a state-wide effort to target city nutritionally needy elderly for home-delivered meals. Findings have been that food insecurity in the inner-city homebound is linked to loss of mobility as well as to poverty and lack of in-home food assistance. Minority elderly whose questionnaire responses indicate food insecurity include diabetics whose disease control is adversely affected by irregular eating. When methods of home assessment have been used to examine the extent to which a home-delivered meals program meets the nutritional needs of recipients, it has been possible to demonstrate that meals recipients show less food insecurity than a comparison group on waiting lists to receive meals.

Aged↗

PubMed2003

Economic impact of extended time on peritoneal dialysis as a result of using polyglucose: the application of a Markov chain model to forecast changes in the development of the ESRD programme over time.

BACKGROUND: The use of polyglucose as a peritoneal dialysis (PD) fluid extends time on PD treatment. It is anticipated, therefore, that the share of patients treated with PD will be positively influenced. The relationship between extension of PD treatment time and an increase of the PD treatment share, however, is complex and needs further investigation. In this paper, a Markov chain model was applied to investigate the impact of extended time on PD treatment for the PD share in all dialysis patients in The Netherlands. Furthermore, the economic impact of the extended time on treatment (ETOT) was explored. METHODS: Scenarios were forecast over a 10 year period using aggregate data from the End-Stage Renal Registry in The Netherlands (Renine). Three scenarios were simulated in which the median PD technique survival was extended by 8, 10 and 12 months. Two other scenarios explored the impact of the combined effect of ETOT of 10 months together with a 10% and 20% increase of PD inflow shares. Reductions of costs to society due to ETOT were estimated using Dutch cost data on renal replacement therapies. RESULTS: PD share increases from 30.0% in the null scenario to 34.5% in the scenario with an ETOT of 10 months and an increased PD inflow share of 20%. The reduction in total costs to society of the renal replacement therapies is 0.96%. The average societal costs per discounted patient year for haemodialysis (HD) are 84 100 euros. For PD, these costs are 60 300 euros. A shift from HD to PD results in average cost savings of 28% per patient year. CONCLUSIONS: In view of high dialysis costs to society, a reduction of 0.96% can be considered to be relevant for healthcare policy makers.

Adolescent↗

PubMed1998

Urban-rural variations in suicides and undetermined deaths in England and Wales.

BACKGROUND: Given that a high proportion of undetermined deaths are thought to be suicides, the objective of the study was to compare the geography of the two verdicts, with emphasis on urban-rural differences, to determine whether the likelihood of a death being classified as suicide varies according to location. METHODS: Standardized mortality ratios (SMRs) were mapped for the local authority districts of England and Wales, using data aggregated over the period 1989-1992. Districts were classified according to population density, and SMRs calculated for each quartile. Finally, regression equations were obtained to model the relationship of suicide and undetermined death with a series of risk factors. RESULTS: Both male and female undetermined deaths showed a significant deficit in the most sparsely populated districts and a significant excess in the most densely populated districts. Female suicides were also significantly high in densely populated districts, but male suicides were highest in the most rural areas (SMR 110, 95 per cent confidence intervals 105-115). District variations in both verdicts were associated with the proportion of single-person households for both sexes, but male suicides and male undetermined deaths were associated with additional predictors, consistent with their distinct geographical distributions. CONCLUSIONS: Differences in suicide methods, the likelihood of communicating suicidal intent and, perhaps, variations in access to psychiatric services might be contributory factors to the observed differences between the verdicts. The results suggest that recorded suicides are a biased subset of actual suicides, particularly for males, and that the study of suicide verdicts alone is potentially misleading.

England↗

PubMed1996

Outcomes in cardiopulmonary rehabilitation.

Physical therapists, as integral members of the multidisciplinary team in cardiac and pulmonary rehabilitation, should be knowledgeable about methods for assessing outcomes for their patients, and they need to understand the value of aggregated data in improving interventions. Definitions are discussed, and appropriate data used to monitor function are identified, including data used in the assessment of well-being. Results of outcome studies from current cardiac and pulmonary literature are presented. A discussion of how to select outcomes to assess and the value of outcome information for program management is included. Therapists are in a position to encourage and participate in widespread, collaborative measurement of disease-specific clinical outcomes, patient functioning, and well-being, which should improve the effectiveness and efficiency of cardiopulmonary rehabilitation.

Cost-Benefit Analysis↗

PubMed2006

Prevalence of problematic and injecting drug use for Drug Action Team areas in England.

BACKGROUND: National and local monitoring of policies on illicit drug use requires information on the number of problematic drug users in a country. This article reports the findings from a study that estimated the number of problematic and injecting drug users for all Drug Action Teams (DATs) in England for 2001. METHODS: The Multiple Indicator Method (MIM) is a statistical technique for using aggregated data to estimate numbers of drug users across a large number of areas. The MIM was used to combine eight indicators available for all DATs, with prevalence estimates available from a small number of DATs. The indicators were drug possession and supply offences, arrest referrals, people recorded in drug treatment databases, methadone prescriptions, drug-related hospital episodes, drug-related deaths and DATs' Townsend score. The latter is a measure of material deprivation. A three-stage process involved, (i) factor analysis of the drug indicators, (ii) regression linking factor scores to known prevalence estimates and (iii) imputation of estimates to all other DATs. RESULTS: Factor analysis yielded two statistically significant factors underlying the drug indicators in 150 DATs in England. The estimated prevalence rate of problematic drug use in the DATs varied from 0.2 to 1.5 per cent of the population. The estimated average number of problematic drug users per DAT was 1943 (standard deviation = 1300). The estimated average number of injecting drug users per DAT was 627 (standard deviation = 572). The estimates for England in 2001 were 287,670 (population rate = 0.64 per cent) problem drug users, and 93,185 (population rate = 0.23 per cent) injecting drug users. CONCLUSIONS: Although the model cannot take account of specific local factors, the results are likely to be accurate in areas that do not have these idiosyncrasies. The estimated prevalence figures provide a basis for all DATs to assess their contact rates with problematic and injecting drug users.

Adolescent↗

PubMed2001

Toward measuring the impact of ecological disintegrity on human health.

Ecological integrity refers to the ability of environmental life-support systems to sustain themselves in the face of human-induced impacts. We used a correlational, aggregate-data study design to explore whether life expectancy, as a general measure of population health, is linked to large-scale declines in ecological integrity. Most of the data were obtained from World Resources Institute publications. Selected surrogate measures of ecological integrity and gross domestic product (GDP) per capita (as a socioeconomic confounder) were modeled, for the first time, using linear regression techniques with life expectancy as the health outcome. We found a modest relation between ecological integrity and life expectancy, but the direction of the association was inconsistent. When GDP per capita was controlled, the relation between ecological integrity and life expectancy was lost. GDP per capita was the overwhelming predictor of health. Any relation between ecological integrity and health may be mediated by socioeconomic factors. The effect of declines in ecological integrity may be cushioned by the exploitation of ecological capital, preventing a direct association between measures of exposure and outcome. In addition, life expectancy may be too insensitive a measure of health impacts related to ecological decline, and more sensitive measures may need to be developed.

Cross-Sectional Studies↗

PubMed1990

Thrombin activity induced by balloon angioplasty of the coronary artery in Macaca fascicularis (cynomolgus monkey).

In this paper we address the question of whether balloon angioplasty induces thrombin action. In the studies reported here we measured fibrinopeptide A levels in a group of atherosclerotic monkeys undergoing coronary angioplasty. A blood collection catheter was introduced into the inferior vena cava through a femoral vein, and the angioplasty catheter introduced via the femoral artery. Heparin was administered immediately after insertion of the arterial catheter. Serial blood samples were collected for 20 min before angioplasty and for 10 min after angioplasty. Baseline levels of FpA were high, presumably in response to the trauma of introducing the catheters. After heparin administration the FpA concentration declined with a half-time of 1.1 min. In response to balloon inflation there was a clear increase in the concentration of FpA, despite the presence of a therapeutic concentration of heparin. The magnitude of the FpA rise was markedly different between animals, but was evident in the aggregate data after subtraction of background levels of FpA. By integration of the plasma FpA concentration curve, the amount of fibrinogen converted to fibrin in response to angioplasty was calculated to be approximately 0.4 mg/animal. We conclude that angioplasty induces significant activation of the coagulation system.

Angioplasty, Balloon, Coronary↗

PubMed1994

Impact of AIDS on premature mortality in Amsterdam, 1982-1992.

OBJECTIVE: To study the impact of AIDS on premature mortality in the city of Amsterdam (1982-1992). METHODS: We combined aggregated data from the Netherlands Central Bureau for Statistics with data from the municipal death and population registry and data from the Amsterdam AIDS surveillance system to calculate age standardized mortality rates for men aged 15-64 years and 25-54 years and working years of potential life lost before 65 years (WYPLL). RESULTS: AIDS was the leading cause of death for men aged 25-54 years in Amsterdam from 1990 onwards, and the third leading cause of death for men aged 15-64 years in 1991. In this larger age group AIDS will probably become the leading cause of death in the coming years. In 1991, AIDS was already the leading cause of WYPLL before 65 years for men in the 15-64 age group. Without AIDS, there would have been a decrease in premature WYPLL from 1982 onwards; however, because of AIDS the number of WYPLL is increasing again. CONCLUSION: AIDS has had a significant impact on the pattern of premature mortality in Amsterdam in the period 1982-1992. Its impact will probably increase over the next few years.

Acquired Immunodeficiency Syndrome↗

PubMed1999

Flumazenil in drug overdose: randomized, placebo-controlled study to assess cost effectiveness.

OBJECTIVE: To investigate cost effectiveness of administration of flumazenil to patients presenting with suspected acute drug overdose. DESIGN: Double-blind, prospective, placebo-controlled randomized study. SETTING: University teaching hospital. PATIENTS: Forty-three adults presenting with suspected drug overdose and having a Glasgow Coma Scale (GCS) score of <13. Patients with known benzodiazepine/tricyclic ingestion were excluded. INTERVENTIONS: Intravenous administration of flumazenil (up to 2 mg) or placebo. MEASUREMENTS AND MAIN RESULTS: Individual patient costs were assessed and data aggregated for each treatment group. Major diagnostic and therapeutic interventions were recorded and between group comparisons performed. Clinical response to study drug administration was assessed by obtaining pre- and post-drug GCS scores and observation of the patient for at least 180 mins for signs of resedation. Aggregate cost or number of major diagnostic and therapeutic interventions were not different between groups. Patients randomized to the flumazenil group showed a marked increase in GCS score (7.4 to 11.8) compared with those in the placebo group (8.2 to 8.6). CONCLUSION: Use of flumazenil in intentional drug overdose of unknown etiology is not cost effective.

Adolescent↗

PubMed2000

Integrated risk assessment and feedback reporting for clinical decision making in a Medicare Risk plan.

The challenge of tapping into the rich resource of population-based, aggregated data to inform and guide clinical processes remains one of the largely unrealized potentials of managed care. This article describes a multifaceted approach of using health-related data to support providers in clinical decision making as an adjunct to case management and primary care delivery. The goal is to provide data that can be used for clinical decision making that is population based, yet individualized for specific patient care situations. Information reporting holds great potential in the clinical care of patients because it can be used to identify persons who could benefit from early detection, intervention, or treatment. It has been suggested that one of the keys to success in managed Medicare is the timely use of information that is detailed, comprehensive, and real-time describing key parameters of clinical encounters.

Aged↗

PubMed1992

The once-daily dose regimen of carvedilol: a meta-analysis approach.

Establishing the overall efficacy or safety of a drug requires a unified methodological approach and analysis of all clinical trials that are intended to be summarized. As an example, this article presents the aggregated dose-response relationship and a subgroup analysis (by age) over all studies of the antihypertensive drug carvedilol. The clinical end points were change from baseline of blood pressure and pulse after 2-4 weeks of treatment with a once-daily dose regimen. All antihypertensive trials were reanalyzed using an intent-to-treat principle. Aggregated data (mean, standard deviation, sample size) for each random group within each study were then combined by means of meta-analysis. The results show that the main patient population can be treated adequately with 25 mg of carvedilol q.d. The dose-response curve shows a typical sigmoid shape: a steeper increase from 12.5 to 25 mg of carvedilol and a following flat part (25, 50, and 100 mg of carvedilol q.d.). There is a considerable variation of the results between studies, which is much bigger than the dose-response effect. Most of this variation is due to monocentric trials.

Adult↗

PubMed1984

Emergency bay thoracotomy.

In recent years, there has been increased debate on the indications for and value of thoracotomies done in the Emergency Department for victims of trauma. The current literature, unfortunately, does not resolve many points of contention surrounding this procedure. Using strict terms to define Emergency Bay Thoracotomy (EBT), 89 consecutive patients seen over a 2-year period in a Trauma Unit were retrospectively reviewed and analyzed. Eighty-five per cent of the patients had no vital signs on arrival, yet the procedure proved to be valuable in sustaining life in 17% of patients, two thirds of whom were discharged, 90% with normal findings. A progressive increase in survival rate was observed with increased use of the procedure. A review of the prognostic factors found in this study and comparison with other published studies indicates that clear definition of the patient population and patient status is essential before aggregated data are used as a basis for therapeutic policies. Educational and research efforts must focus on determining which patients have zero prognosis after initiating resuscitation, rather than on denying care to any group, even when only a few will respond.

Adolescent↗

PubMed1983

Measuring the impact of programs for mothers and infants on prenatal care and low birth weight: the value of refined analyses.

During the past two decades, intervention strategies designed to improve the health status of mothers and infants have been widely disseminated, yet relatively few have been evaluated for effectiveness. Moreover, most reported investigations have involved straightforward comparisons of aggregate data, employing various degrees of methodological control. In this study, vital statistics data were used to assess the effects of the North Carolina Maternity and Infant Care (MIC) Project on use of prenatal care and low birth weight. A weighted least squares procedure was used to control for selected maternal characteristics and identify significant interactions. Analyses of total population data indicated only minor MIC effects. However, more careful scrutiny of subpopulation data suggests that MIC impacts differed across categories of maternal risk status, with the greatest influence observed among mothers and infants at greatest risk. These findings raise several questions regarding the genesis of differential effects and suggest areas of special concern in conducting, interpreting, and using evaluations of programs for mothers and infants.

Adolescent↗