Biomedical subjects
Publications and source records attributed to J A Hanley.
In this paper we describe the main features of a small-scale plotting language used to produce medical data forms. It requires no previous knowledge of computers and is easily learned and used. Its use at the Statistical Laboratory at the State University of New York at Buffalo has resulted in considerable time savings, a greater unification of data items and data forms, and an increase in the quality of data collected.
Cigarette smoking behaviour among the young was examined in the light of the responses of over 78 000 students to a 1972 questionnaire survey of Canadian schools. As few as 2% (8-year-old girls) and as many as 60% (16 year--old boys) were smoking one or more cigarettes per week. The prevalence of smoking was higher than that reported in earlier studies. Students, particularly girls, were beginning to smoke at progressively earlier ages. Some differences in smoking behaviour were found between regions, language groups and groups of children whose parents did or did not smoke. Recognition of immediate rather than long-term effects of smoking on health was reported as an important consideration in not smoking.
In this study, 16 experienced oncologists each measured 12 simulated tumor masses employing their usual clinical methods. Unknown to the oncologists, two pairs of these tumors were identical in size. This permitted a total of 64 measurement comparisons of the same investigator measuring the same size mass and 1920 comparisons of different investigators measuring the same size mass. If a 50% reduction in the product of perpendicular diameters is accepted as a criterion, the objective response rate due to measuring error alone was 7.8% by the same investigator and 6.8% by different investigators. If a 25% reduction criterion is used, the respective "placebo" response rates were 19% and 25%. In the clinical setting it is recommended that the 50% reduction criterion be employed and that the investigator should anticipate an objective response rate of 5 to 10% due to human error in tumor measurement.
Twenty-four subjects smoked two brands of filter-tipped cigarettes delivering different amounts of nicotine, on the following 4-week schedule: 1. Smoking their usual brand for 1 week. 2. Smoking another brand similar in size, but delivering less nicotine, for 2 weeks. 3. Reverting to their usual brand for 1 week. The amount of nicotine entering the mouth, defined as the mouth-level exposure, was estimated from a determination of the amount of nicotine trapped in the filter of each cigarette smoked. The results indicate a substantial variation in mouth-level exposure for the subjects studied, even among smokers of cigarettes that deliver similar amounts of nicotine when smoked on a machine under standard conditions. For the majority of subjects, however, changing to a lower nicotine cigarette reduced the total daily mouth-level exposure to nicotine and, therefore, presumably the total tar intake.
53 patients with intractable malignant diseases that were treated with a new alkylating agent, 4-N,N-bis (2-chloroethyl) amino phenyl N (P-carboxyphenyl) carbanate, also knows as 'IC-140' were evaluated. The records of an additional 41 patients entered on this study could not be assessed from the standpoint of toxicity. At the dose level of 150 mg/m2/week, severe leukopenia (less than 2,000) and thrombocytopenia ( less than 75,000) were encountered in 23 of 34 patients. On the other hand, at the 100 mg/m2/week dose level, the severe toxicity was reduced to 8 out of 19 patients. Tumor response was evaluated in 43 patients. The overall response was 23% (29% at the 150 mg/m2, 13% at the 100 mg/m2) and the duration of the response varied from 3 to 32 weeks with a mean duration of 13 weeks. Responses were noted in patients with ovarian, renal, lung, hepatic, breast carcinomas and lymphosarcoma.
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CONTEXT: Rising costs of medications and inequities in access have sparked calls for drug policy reform in the United States and Canada. Control of drug expenditures by prescription cost-sharing for elderly persons and poor persons is a contentious issue because little is known about the health impact in these subgroups. OBJECTIVES: To determine (1) the impact of introducing prescription drug cost-sharing on use of essential and less essential drugs among elderly persons and welfare recipients and (2) rates of emergency department (ED) visits and serious adverse events associated with reductions in drug use before and after policy implementation. DESIGN AND SETTING: Interrupted time-series analysis of data from 32 months before and 17 months after introduction of a prescription coinsurance and deductible cost-sharing policy in Quebec in 1996. Separate 10-month prepolicy control and postpolicy cohort studies were conducted to estimate the impact of the drug reform on adverse events. PARTICIPANTS: A random sample of 93 950 elderly persons and 55 333 adult welfare medication recipients. MAIN OUTCOME MEASURES: Mean daily number of essential and less essential drugs used per month, ED visits, and serious adverse events (hospitalization, nursing home admission, and mortality) before and after policy introduction. RESULTS: After cost-sharing was introduced, use of essential drugs decreased by 9.12% (95% confidence interval [CI], 8.7%-9.6%) in elderly persons and by 14.42% (95% CI, 13.3%-15.6%) in welfare recipients; use of less essential drugs decreased by 15.14% (95% CI, 14.4%-15.9%) and 22.39% (95% CI, 20.9%-23.9%), respectively. The rate (per 10 000 person-months) of serious adverse events associated with reductions in use of essential drugs increased from 5.8 in the prepolicy control cohort to 12.6 in the postpolicy cohort in elderly persons (a net increase of 6.8 [95% CI, 5.6-8.0]) and from 14.7 to 27.6 in welfare recipients (a net increase of 12.9 [95% CI, 10.2-15.5]). Emergency department visit rates related to reductions in the use of essential drugs also increased by 14.2 (95% CI, 8.5-19.9) per 10 000 person-months in elderly persons (prepolicy control cohort, 32.9; postpolicy cohort, 47.1) and by 54.2 (95% CI, 33.5-74.8) among welfare recipients (prepolicy control cohort, 69.6; postpolicy cohort, 123.8). These increases were primarily due to an increase in the proportion of recipients who reduced their use of essential drugs. Reductions in the use of less essential drugs were not associated with an increase in risk of adverse events or ED visits. CONCLUSIONS: In our study, increased cost-sharing for prescription drugs in elderly persons and welfare recipients was followed by reductions in use of essential drugs and a higher rate of serious adverse events and ED visits associated with these reductions.
The use of hospital databases for research into the respiratory effects of air pollution has been questioned. In an attempt to address that issue, reabstracts of 1,279 discharge records from 14 Montreal hospitals were compared with the universal health insurance database of Quebec. Agreement levels on discharge diagnoses were 94.9% for asthma; 75.5% for all other respiratory diagnoses combined, including upper airway infections, pneumonia, and coronary obstructive pulmonary disease (COPD) (90% after ignoring disagreements between closely related respiratory diagnoses); and 93.1% for a nonrespiratory comparison group. Factors associated with misclassification included use of nonurgent admissions; delays in hospital admission from emergency rooms; and differences in levels of diagnostic agreement between hospitals, age groups, and outcome groups. These should be taken into account in air pollution epidemiologic research in which databases of the kind commonly maintained in North American health care systems are used.
The binormal form is the most common model used to formally fit ROC curves to the data from signal detection studies that employ the "rating" method. The author lists a number of justifications that have been offered for this choice, ranging from theoretical considerations of probability laws and signal detection theory, to mathematical tractability and convenience, to empirical results showing that "it fits!" To these justifications is added another, namely that even if an alternative formulation based on another underlying form (e.g., power law) or model (e.g., binomial, Poisson, or gamma type distributions) were in fact correct, the binormal fit differs so little from the true form as to be of no practical consequence. Moreover, the small lack of fit is unlikely to be demonstrated in practice: it is obscured by the much larger variation that can be attributed to sampling of cases. In addition, even if a very large sample of cases could be studied, the small number of rating categories used does not permit seemingly very different models to be distinguished from one another.
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Receiver operating characteristic (ROC) analysis, which yields indices of accuracy such as the area under the curve (AUC), is increasingly being used to evaluate the performances of diagnostic tests that produce results on continuous scales. Both parametric and nonparametric ROC approaches are available to assess the discriminant capacity of such tests, but there are no clear guidelines as to the merits of each, particularly with non-binormal data. Investigators may worry that when data are non-Gaussian, estimates of diagnostic accuracy based on a binormal model may be distorted. The authors conducted a Monte Carlo simulation study to compare the bias and sampling variability in the estimates of the AUCs derived from parametric and nonparametric procedures. Each approach was assessed in data sets generated from various configurations of pairs of overlapping distributions; these included the binormal model and non-binormal pairs of distributions where one or both pair members were mixtures of Gaussian (MG) distributions with different degrees of departures from binormality. The biases in the estimates of the AUCs were found to be very small for both parametric and nonparametric procedures. The two approaches yielded very close estimates of the AUCs and the corresponding sampling variability even when data were generated from non-binormal models. Thus, for a wide range of distributions, concern about bias or imprecision of the estimates of the AUC should not be a major factor in choosing between the nonparametric and parametric approaches.
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One hundred and ninety-seven patients with measurable metastatic cancer of the colon have been treated with one of four anticancer drugs which have had little prior trial in this disease. Objective tumor responses lasting a median of 9 weeks occurred with 0.5 g/m of streptozotocin given intravenously every week (10 percent), 130 mg/m of CCNU given orally every 6 weeks (10%), 1.0 mg/kg/day of 6-thioguanine given orally (8%), and 3 mg/kg/day of procarbazine given orally (3%). Performance status declined more rapidly with streptozotocin and 6-thioguanine and the median survival time was less (12 and 16 weeks respectively) than with procarbazine and CCNU (23 and 20 weeks respectively). This study suggests that procarbazine given in this way is ineffective but trials of streptozotocin or 6-thioguanine combined with other agents active against colon cancer should ensue as well as further exploration of the usefulness of other nitrosoureas.
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