Biomedical subjects

L E McCamant

Publications and source records attributed to L E McCamant.

9 recordsLinked to original sources

PubMed2000

The validity of medicaid pharmacy claims for estimating drug use among elderly nursing home residents: The Oregon experience.

This study compared computerized Medicaid pharmacy claims data for nursing home residents with chart data to establish how well the claims data identified those receiving drugs within three different psychoactive drug classes (yes/no for each class) and how well the claims estimated total within-class average daily dose. Percent agreement, positive predictive value (PPV), and negative predictive value (NPV) for drug exposure were over 85% for each class. Kappas were excellent for antipsychotics and antidepressants, and good for anxiolytics. Correspondence was lower for average daily dose. Using an algorithm that credits some but not all doses associated with overlapping claims, correlations ranged from 0.97 to 0.66. Agreement on therapeutic dose was excellent for antipsychotics (kappa = 0.81) and fair to good for antidepressants and anxiolytics (kappa = 0.63, and kappa = 0.52, respectively). The findings suggest that Medicaid pharmacy claims data are reasonably accurate for quality assurance and accreditation purposes.

Aged↗

PubMed1991

Pulmonary health risks among northwest loggers.

Spirometry, respiratory symptom questionnaires, and chest radiographs were obtained from 688 loggers in Oregon and Washington. These were compared against previously published National Institute for Occupational Safety and Health studies of nonexposed blue-collar workers to determine if these predictions fit our population. The loggers forced expiratory volume in 1 second and forced vital capacity values were significantly greater than predicted, and their forced expiratory volume in 1 second/forced vital capacity values were less than predicted. The only consistent difference in symptoms between the sample and reference populations was for recent chest illnesses, which were more prevalent in the loggers than in the reference population. The chest radiographs showed a small excess of pleural thickening that we believe is most likely due to chest trauma. We conclude that the National Institute for Occupational Safety and Health studies spirometry prediction equations may not be generalized to other blue-collar populations.

Aged↗

PubMed1990

Long-term reproducibility of tests of small airways function. Comparisons with spirometry.

We used a tracking index to measure the reproducibility of single breath nitrogen test variables (CV/VC, CC/TLC, delta N2/L) and spirometric variables (FEV1 and FEV1/FVC) and to compare the characteristics of individuals whose pulmonary function tracks well with those whose pulmonary function tracks poorly. Data were derived from two cohorts followed longitudinally over a 9-11 year period. All variables were adjusted for age, sex and height by expressing them as Z-scores. In all smoking groups and in both cohorts, the tracking index was highest for FEV1, indicating that this variable was the most reproducible over the period of follow-up; delta N2/L and FEV1/FVC had very similar but slightly lower tracking indices; CV/VC consistently had the lowest tracking indices. Tracking indices were generally higher in smokers than in nonsmokers. The reproducibility of CC/TLC increased over the period of follow-up whereas the FEV1 reproducibility remained constant. We found no significant difference between those with high tracking indices and those with low indices in terms of sex, smoking status, prevalence of respiratory symptoms, history of respiratory disease, and rate of decline of FEV1. We conclude that FEV1 is the most reproducible of the variables examined, both within and between individuals, and that poor tracking or reproducibility are not related to smoking or to the presence of respiratory symptoms or disease.

Adult↗

PubMed1989

Respiratory symptoms, lung function, and mortality in a screening center cohort.

Numerous studies have documented the effects of smoking and reduced pulmonary function on all-cause mortality. The effects of respiratory symptoms are less well studied. This paper examines the joint effects of respiratory symptoms, lung function, and smoking using 11-year mortality data on 698 subjects aged 25 years and older. Copies of death certificates were obtained for all 120 confirmed deaths, and cause of death was coded by a nosologist using the rules of the International Classification of Diseases, Ninth Revision. Symptoms of cough/phlegm, wheeze, and dyspnea were significantly associated with all-cause mortality in separate univariate analyses. On a cause-specific basis, these associations appeared to hold for chronic obstructive pulmonary disease, lung cancer, and vascular disease. Further analysis indicated that, for both smokers and nonsmokers, the presence of chronic cough and/or sputum production was related to mortality only in the presence of wheezing. In addition, among smokers, the presence of both cough/phlegm and wheeze. In addition, among smokers, the presence of both cough/phlegm and wheeze was significantly associated with mortality only among subjects with low initial lung function. Although the limited number of deaths and the nonrandom nature of the cohort limit the generalizability of our findings, it seems clear, based on these results and other published studies, that symptoms of cough, phlegm, and/or wheeze have important adverse health implications even in the absence of smoking and reduced lung function. More studies using common methodological approaches are needed.

Adult↗

PubMed1988

Longitudinal versus cross-sectional estimation of lung function decline--further insights.

This paper explores the extent to which differences in longitudinal versus cross-sectional inference may be influenced by the choice of statistical models. Using lung function data on 524 working men, we first compare the goodness-of-fit and implication for longitudinal decline of a variety of cross-sectional models. We then compare the predicted longitudinal patterns from these models with those observed over a period of four years. In general, both approaches provide qualitatively, if not quantitatively, similar messages concerning the relative effects of smoking and age on lung function decline. Nonetheless, we acknowledge the existence of real selection and cohort effects. Although we recognize the utility of cross-sectional designs, we discourage quantitative comparisons between studies, especially longitudinal versus cross-sectional.

Adult↗

PubMed1988

Does the single-breath N2 test identify the smoker who will develop chronic airflow limitation?

We report here the results of a 9- to 11-yr follow-up of 2 cohorts in which spirometry and the single-breath N2 test were used throughout the follow-up period to determine the usefulness of the single-breath N2 test in identifying the smoker who is experiencing a rapid decline in FEV1 and is therefore likely to be at risk of developing chronic airflow limitation. The analyses are based on 734 subjects tested from 3 to 5 times over the follow-up period; 82 smokers developed an abnormal FEV1 during the follow-up period. Of these, 71 (87%) had had an abnormal single-breath N2 test at some time prior to the FEV1 becoming abnormal. Of the single-breath N2 test variables, CC/TLC was the only one significantly associated with the rate of decline of FEV1 in both cohorts once adjustments were made for age, sex, height, and smoking. We conclude that the single-breath N2 test can be useful in identifying the smoker who is at risk of developing chronic airflow limitation. However, its usefulness is diminished by the high proportion of smokers who have mild functional abnormalities but do not progress to develop chronic airflow limitation. We also find that the single-breath N2 test does not appear to have a useful predictive value in nonsmokers.

Adult↗

PubMed1987

Methodologic issues in the analysis of lung function data.

The forced expiratory volume in one second (FEV1) is routinely used in epidemiologic studies of lung function to assess the presence and severity of obstructive airways disease. Normative prediction equations developed using data from healthy, asymptomatic individuals may then be used both in a clinical setting and to adjust comparisons among risk subgroups for known demographic differences. Unfortunately no concensus has yet developed as to how best to model lung function data. This paper addresses this issue in a systematic manner using data derived from two cohorts followed over a period of 9-11 years. We compare a variety of cross-sectional and longitudinal models for FEV1, show how they may be expressed as members of a larger class of general linear models, and discuss goodness-of-fit procedures for comparing them. We found little objective evidence for discriminating among these models; only those fit to FEV1/ht3 performed poorly. We argue on subjective grounds for the use of models based on FEV1 as a function of age, height and their interactions.

Adult↗

PubMed1986

A four-year prospective study of the respiratory effects of volcanic ash from Mt. St. Helens.

This report describes the 4-yr follow-up of 712 loggers exposed over an extended period to varying levels of fresh volcanic ash from the 1980 eruptions of Mt. St. Helens. Concerns related to the irritant effect the ash might have on the airways and also to its fibrogenic potential if exposures were intense and continued over many years. Our subjects were divided into 3 groups: high, low, and no exposure. Baseline testing was begun in June 1980, 1 month after the major eruption, and follow-up testing continued on an annual basis through 1984; 88% of the loggers have been tested at least 3 times. Analysis of lung function data showed that a significant, exposure-related decline in FEV1 occurred during the first year after the eruption. The decline was short-lived, however, and by 1984 the differences between exposure groups were no longer significant. Self-reported symptoms of cough, phlegm, and wheeze showed a similar pattern. No ash-related changes were seen in chest roentgenograms taken in 1980 and in 1984. Our findings are consistent with the hypothesis that the inhaled ash caused mucus hypersecretion and/or airway inflammation that reversed when the exposure levels decreased. The ash levels to which the loggers were exposed were low compared with permissible occupational levels for nuisance dusts, but generally higher than the total suspended particulate levels permissible in ambient air.

Adolescent↗

PubMed1986

Relationship between serum IgE and cross-sectional and longitudinal FEV1 in two cohort studies.

Evidence is accumulating that elevated levels of serum IgE may play a role in the pathogenesis of chronic airflow obstruction. We examined this question using data on 863 subjects drawn from two cohort studies which we have followed over a period of nine to 11 years. One, the Portland cohort, represents a working population aged 25 to 55 years at baseline. The second, the Screening Center cohort, spans a wider age range (18 to 87 years at baseline) and is biased towards respiratory disease. Spirometric tests and respiratory symptom questionnaires have been administered five times over a nine-year period for the Portland cohort, and over an 11-year period for the Screening Center cohort. IgE was measured one time towards the end of the follow-up. Our data confirm the finding that smokers tend to have higher IgE levels than nonsmokers. For the combined sample, geometric mean levels of IgE were 31.0 IU/ml among smokers and 17.4 IU/ml among nonsmokers. Levels among ex-smokers were intermediate. Among smokers, IgE was not related to either amount smoked or pack-years. Cross-sectionally, FEV1 was inversely related to IgE in the Screening Center cohort, but not in the Portland cohort study. Among smokers, this association was only present for those subjects with symptoms of chronic bronchitis (chronic cough/sputum production). We found no association of IgE with longitudinal rate of decline of FEV1 in either cohort. These findings are consistent with other studies and support the hypothesis that serum IgE is inversely related to function level cross-sectionally, but is not predictive of rate of decline of lung function.

Adult↗