Adverse outcomes of frailty in the elderly: the Rotterdam Study

To investigate the prevalence of frailty in a Dutch elderly population and to identify adverse health outcomes associated with the frailty phenotype independent of the comorbidities. Cross-sectional and longitudinal analyses within the Rotterdam Study (the Netherlands), a prospective population-based cohort study in persons aged ≥55 years. Frailty was defined as meeting three or more of five established criteria for frailty, evaluating nutritional status, physical activity, mobility, grip strength and exhaustion. Intermediate frailty was defined as meeting one or two frailty criteria. Comorbidities were objectively measured. Health outcomes were assessed by means of questionnaires, physical examinations and continuous follow-up through general practitioners and municipal health authorities for mortality. Of 2,833 participants (median age 74.0 years, inter quartile range 9) with sufficiently evaluated frailty criteria, 163 (5.8 %) participants were frail and 1,454 (51.3 %) intermediate frail. Frail elderly were more likely to be older and female, to have an impaired quality of life and to have fallen or to have been hospitalized. 108 (72.0 %) frail participants had ≥2 comorbidities, compared to 777 (54.4 %) intermediate frail and 522 (44.8 %) non-frail participants. Adjusted for age, sex and comorbidities, frail elderly had a significantly increased risk of dying within 3 years (HR 3.4; 95 % CI 1.9–6.4), compared to the non-frail elderly. This study in a general Dutch population of community-dwelling elderly able to perform the frailty tests, demonstrates that frailty is common and that frail elderly are at increased risk of death independent of comorbidities.     

Methods to improve the estimation of time-to-event outcomes when data is de-identified

Technological advancements in recent years have sparked the use of large databases for research. The availability of these large databases has administered a need for anonymization and de-identification techniques, prior to publishing the data. This de-identification alters the data, which in turn can impact the results derived post de-identification and potentially lead to false conclusions. The objective of this study is to investigate if alterations to a de-identified time-to-event data set may improve the accuracy of the estimates. In this data set, a missing time bias was present among censored patients as a means to preserve patient confidentiality. This study investigates five methods intended to reduce the bias of time-to-event estimates. A simulation study was conducted to evaluate the effectiveness of each method in reducing bias. In situations where there was a large number of censored patients, the results of the simulation showed that Method 4 yielded the most accurate estimates. This method adjusted the survival times of censored patients by adding a random uniform component such that the modified survival time would occur within the final year of the study. Alternatively, when there was only a small number of censored patients, the method that did not alter the de-identified data set (Method 1) provided the most accurate estimates.     

Methods to achieve high interrater reliability in data collection from primary care medical records

PURPOSE We assessed interrater reliability (IRR) of chart abstractors within a randomized trial of cardiovascular care in primary care. We report our findings, and outline issues and provide recommendations related to determining sample size, frequency of verification, and minimum thresholds for 2 measures of IRR: the κ statistic and percent agreement.METHODS We designed a data quality monitoring procedure having 4 parts: use of standardized protocols and forms, extensive training, continuous monitoring of IRR, and a quality improvement feedback mechanism. Four abstractors checked a 5% sample of charts at 3 time points for a predefined set of indicators of the quality of care. We set our quality threshold for IRR at a κ of 0.75, a percent agreement of 95%, or both.RESULTS Abstractors reabstracted a sample of charts in 16 of 27 primary care practices, checking a total of 132 charts with 38 indicators per chart. The overall κ across all items was 0.91 (95% confidence interval, 0.90–0.92) and the overall percent agreement was 94.3%, signifying excellent agreement between abstractors. We gave feedback to the abstractors to highlight items that had a κ of less than 0.70 or a percent agreement less than 95%. No practice had to have its charts abstracted again because of poor quality.CONCLUSIONS A 5% sampling of charts for quality control using IRR analysis yielded κ and agreement levels that met or exceeded our quality thresholds. Using 3 time points during the chart audit phase allows for early quality control as well as ongoing quality monitoring. Our results can be used as a guide and benchmark for other medical chart review studies in primary care.     

Study design in qualitative research--2: Sampling and data collection strategies

In two prior papers in our series on qualitative research [Frankel & Devers (2000a, 2000b) Qualitative research: a consumer's guide, Education for Health, 13, 113-123; Frankel & Devers (2000) Study design in qualitative research-1: developing research questions and assessing research needs, Education for Health, 13, 251-261], we examine two critical issues in qualitative research design: sampling, including identifying and negotiating access to research sites and subjects, and data collection and management. We describe these two key steps in the qualitative research design process, discuss challenges that often emerge when pursuing these steps, and provide guidelines for addressing them. Qualitative research most often uses "purposive," rather than random, sampling strategies. A good understanding of these sampling strategies and why they are used is central to designing a credible qualitative study. In addition, given the real-world context in which most qualitative research is carried out, identifying and negotiating access to research sites and subjects are critical parts of the process. We also provide suggestions for developing and maintaining productive and mutually satisfying research relationships with sites and subjects. Finally, data collection and management are often neglected subjects in qualitative research. We offer practical advice on how to collect and manage qualitative data, including factors to consider when deciding how structured the data collection process should be, the pros and cons of audio- and/or videotaping compared with note-taking, and tips for writing up field notes and document management. A forthcoming, final paper in the series will focus on qualitative data analysis and the publication of qualitative research results.     

Discovering carcinogens in the occupational environment. Methods of data collection and analysis of a large case-referent monitoring system

A multi-cancer site, multi-factor, case-referent study was undertaken to generate hypotheses about possible occupational carcinogens. About 20 types of cancer were included. Incident cases among men aged 35-70 years and diagnosed in any of the major Montreal hospitals were eligible. Probing interviews were carried out for 3 726 eligible cases. The interview was designed to obtain detailed lifetime job histories and information on potential confounders. Each job history was reviewed by a team of chemists who translated it into a history of occupational exposures. These occupational exposures were then analyzed as potential risk factors in relation to the sites of cancer included. For each site of cancer analyzed, referents were selected from among the other sites in the study. The analysis was carried out in stages. First a Mantel-Haenszel analysis was undertaken of all cancer-substance associations, stratifying on a limited number of covariates, and, then, for those associations which were noteworthy in the initial analysis, a logistic regression analysis was made taking into account all potential confounders. This report describes the fieldwork and analytical methods.     

Dietary iron and risk of myocardial infarction in the Rotterdam Study

Free iron has been implicated in lipid peroxidation and ischemic myocardial damage, and it has been suggested that iron is an independent risk factor for myocardial infarction. The authors investigated whether dietary iron is associated with an increased risk of fatal and nonfatal myocardial infarction in the Rotterdam Study, a community-based prospective cohort study of 7,983 elderly subjects in Rotterdam, the Netherlands. The study sample consisted of 4,802 participants who at baseline had no known history of myocardial infarction and for whom dietary data were available. From 1990 to 1996, 124 subjects had a myocardial infarction. No association was observed between total iron intake and risk of myocardial infarction after adjustment for age and sex (relative risk for the highest vs. the lowest tertile of intake = 0.89, 95% confidence interval (CI) 0.55-1.45, p for trend = 0.640). Heme iron intake was positively associated with risk of myocardial infarction (relative risk for the highest vs. the lowest tertile of intake = 1.83, 95% CI 1.16-2.91, p for trend = 0.008) after adjustment for age and sex, and this association persisted after multivariate adjustment (relative risk = 1.86, 95% CI 1.14-3.09, p for trend = 0.010). A distinction between fatal and nonfatal cases of myocardial infarction indicated that the association of heme iron with myocardial infarction was more pronounced in fatal cases. The results suggest that a high dietary heme iron intake is related to an increased risk of myocardial infarction and that it may specifically affect the rate of fatality from myocardial infarction.     

Feasibility and acceptability of intensive longitudinal data collection of activity and patient-reported outcomes during chemotherapy for breast cancer

Quality of Life Research - Ecological momentary assessment (EMA) may help us better understand biopsychosocial determinants and outcomes of physical activity during chemotherapy, but may be...     

The paranoia of data collection in Hungary and the health system

There is no integrated national health database in Hungary. The currently available database collects only important parameters relevant for funding, and these include data only from publicly funded providers. Patient data in different hospitals are inaccessible from outside but, because of insufficient filing and closures of hospitals, they are often not available in the hospital either. The author encourages to establish a medical database in Hungary by showing foreign examples, thus providing both medical staff and research with authentic patient data.     

Alternatives in the collection and analysis of food frequency interview data

In addition to frequency of consumption, a food frequency questionnaire may assess amount consumed, often by using food models, and the stability of diet. A food frequency interview directed at preformed vitamin A and beta-carotene was administered to 130 cases and 309 controls in an ongoing population-based case-control study of lung cancer in New Mexico. The questionnaire measured frequency, amount, and stability of consumption for 55 food items. Different combinations of responses to these three types of questions were used to calculate indices of total vitamin A consumption. The index based on frequency alone had the lowest value and increased significantly when amount was combined with frequency. Consideration of past consumption had relatively little effect on absolute and relative estimates of intake. Spearman rank order correlations between index pairs were high. These results suggest that the use of frequency alone is appropriate when the objective of data collection is to establish subjects' relative intake of specific nutrients.