What differentiates primary care physicians who predominantly prescribe diuretics for treating mild to moderate hypertension from those who do not? A comparative qualitative study.

BACKGROUND: Thiazide diuretics are cost-effective for the treatment of mild to moderate hypertension, but physicians often opt for more expensive treatment options such as angiotensin II receptor blockers or angiotensin converting enzyme inhibitors. With escalating health care costs, there is a need to elucidate the factors influencing physicians' treatment choices for this highly prevalent chronic condition. The purpose of this study was to describe the characteristics of physicians' decision-making process regarding hypertension treatment choices. METHODS: A comparative qualitative study was conducted in 2009 in the Canadian province of Quebec. Overall, 29 primary care physicians--who are also participating in an electronic health record research program--participated in a semi-structured interview about their prescribing decisions. Physicians were categorized into two groups based on their patterns of prescribing antihypertensive drugs: physicians who predominantly prescribe diuretics, and physicians who predominantly prescribe drug classes other than diuretics. Cases of hypertension that were newly started on antihypertensive therapy were purposely selected from each physician's electronic health record database. Chart stimulated recall interview, a technique utilizing patient charts to probe recall and provide context to physician decision-making during clinical encounters, was used to elucidate reasons for treatment choices. Interview transcripts were synthesized using content analysis techniques, and factors influencing physicians' decision making were inductively generated from the data. RESULTS: We identified three themes that differentiated physicians who predominantly prescribe diuretics from those who predominantly prescribe other drug classes for the initial treatment of mild to moderate hypertension: a) perceptions about the efficacy of diuretics, b) preferred approach to hypertension management and, c) perceptions about hypertension guidelines. Specifically, physicians had differences in beliefs about the efficacy, safety and tolerability of diuretics, the most effective approach for managing mild to moderate hypertension, and in aggressiveness to achieve treatment targets. Marketing strategies employed by the pharmaceutical industry and practice experience appear to contribute to these differences in management approach. CONCLUSIONS: Physicians preferring more expensive treatment options appear to have several misperceptions about the efficacy, safety and tolerability of diuretics. Efforts to increase physicians' prescribing of diuretics may need to be directed at overcoming these misperceptions.

Patient and nurse staffing characteristics associated with high sitter use costs.

AIM: This paper is a report of a study of the relationships between patient health conditions, nurse staffing characteristics and high sitter use costs. BACKGROUND: Increasing recourse to patient sitters is a major cost concern to hospitals. To reduce these expenses, we need to understand better the factors associated with high sitter use costs. METHODS: From a cohort of 43,212 medical/surgical patients admitted to an academic health centre in Montreal (Canada) in 2007 and 2008, all 1151 patients who received a sitter were selected. We applied multivariate logistic regression, using the Generalized Estimating Equation framework, to estimate the relationships between patient health conditions, nurse staffing characteristics and being in the upper two quintiles of sitter costs, vs. the lower three. RESULTS: The median sitter cost per patient, in Canadian dollars, was $772·35 (IQR = $1737·84); and $2397·00 (IQR = $3085·03) among the patients with high sitter use costs. In multivariate analyses, dementia, delirium and other cognitive impairments (OR = 1·49; 95% CI = 1·01-2·22) and schizophrenia and other psychoses (OR = 2·42; 95% CI = 1·08-5·76) increased the likelihood of high sitter use costs. In addition, every additional worked hour per patient per day by Registered Nurses (OR =0·33; 95% CI = 0·27-0·39) and by patient care assistants (OR = 0·11; 95% CI = 0·08-0·15) reduced the likelihood of high sitter use costs. Conclusion. Circumstances of understaffing and patients having psycho-geriatric conditions are associated with high sitter use costs. Improving staffing and providing additional resources to support the care of psycho-geriatric patients may lower these expenses.

Registered nurses' job demands in relation to sitter use: nested case-control study.

BACKGROUND: Increases in overtime and absenteeism among registered nurses (RNs), in conjunction with a workforce having less experience, have resulted in high RN job demands. At the same time, there has been an increase in hospitals' use of patient sitters (i.e., unskilled attendants), but it is not known if these two changes are correlated. OBJECTIVE: The aim of this study was to determine if indicators of RN job demands, specifically overtime, absenteeism, and experience, are related to greater sitter use. METHOD: A nested case-control study design was used. All patients who were assigned a sitter (cases) were selected from a cohort of 43,212 medical and surgical patients who had been admitted to an academic health center in Montreal (Canada) in 2007 and 2008. For each case (n = 1,179), up to four controls (n = 4,167) were selected randomly among patients who did not receive a sitter. Multivariate logistic regression, within a generalized estimating equation framework, was used to assess the association between RN job demand indicators and sitter use, while controlling for other risk factors for sitter use. RESULTS: Compared with controls, patients who were assigned sitters had been subject to high rates of RN overtime and absenteeism and lower RN cumulative experience in the period prior to sitter use. Each additional hour of RN overtime increased the likelihood of sitter use by 108% (odds ratio = 2.08, 95% confidence interval = 1.32-3.29). Every 5 years of collective RN experience reduced the odds of sitter use by 23% (odds ratio = 0.77, 95% confidence interval = 0.66-0.89). Absenteeism was not associated with sitter use. DISCUSSION: High RN overtime and collective inexperience are associated with greater sitter use. A possible explanation is that sitters are used to palliate failures to meet high job demands. Further research is required to assess the impact of sitter use on patient outcomes.

Non-participation bias in health services reseach using data from an integrated electronic prescribing project: the role of informed consent / Sego por falta de participación en la investigación de los servicios de salud al usar datos de un proyecto integrado de prescripción electrónica: el papel del consentimiento informado / Sesgo pela falta de participação na pesquisa dos serviços de saúde ao usar dados de um projeto integrado de prescrição eletrônica: o papel do consentimento informado

Electronic prescribing potentially reduces adverse outcomes and provides critical information for drug safety research but studies may be distorted by non-participation bias. 52,507 patients and 28 physicians were evaluated to determine characteristics associated with consent status in an electronic prescribing project. Physicians with less technology proficiency, seeing more patients, and having patients with higher fragmentation of care were less likely to obtain consent. Older patients with complex health status, higher income, and more visits to the study physician were more likely to consent. These systematic differences could result in significant non-participation bias for research conducted only with consenting patients.

La prescripción electrónica reduce, potencialmente, los resultados adversos. y proporciona información crítica para una investigación segura en drogas, pero los estudios pueden ser distorsionados por un sesgo por falta de participación. Se evaluó a 52.505 pacientes y a 28 médicos para determinar características asociadas con el estatus del consentimiento en un proyecto de prescripción electrónica. Los médicos con menor eficiencia tecnológica, con más cantidad de pacientes que, además, mostraban mayor fragmentación en su atención, presentaban menor opción de obtener consentimiento. Los pacientes de más edad, con estatus de salud complejo, mayor ingreso y con más visitas al médico a cargo, manifestaban mayor disposición a consentir. Estas diferencias sistemáticas podrían desembocar en un sesgo significativo por falta de participación en la investigación llevada a cabo sólo con pacientes con consentimiento.

A prescrição eletrônica reduz potencialmente os resultados adversos e proporciona informação crítica para uma pesquisa segura em drogas, porém os estudos podem ser destorcidos por um sesgo por falta de participação. Avaliou-se 52.505 pacientes e a 28 médicos para determinar características associadas com o estatus do consentimento num projeto de prescrição eletrônica. Os médicos com menor eficiência tecnológica, com mais quantidade de pacientes que os outros, mostravam maior fragmentação em sua atenção, apresentavam menos opção para conseguir o consentimento. Os pacientes mais idosos, com estudos de saúde maiôs complexos, maiores salários e com mais visitas ao médico, manifestavam maior disposição de consentir. Estas diferenças sistemáticas poderiam desembocar num erro significativo por falta de participação na pesquisa levada a cabo somente com pacientes que consentiram.

Use of time-dependent measures to estimate benefits of beta-blockers after myocardial infarction.

PURPOSE: To estimate the reduction in all-cause mortality conferred by beta-blockers in a population-based cohort of elderly survivors of myocardial infarction during the year following hospital discharge. METHODS: A dynamic retrospective cohort was assembled from persons aged 66 years and over surviving myocardial infarction in Quebec between 1990 and 1993. Information on hospitalizations was linked to medication and physician claims, demographic characteristics and vital status. Subjects prescribed beta-blockers at hospital discharge had fewer comorbid medical conditions, less pre-existing cardiovascular disease and less severe infarcts. To control for these differences, analyzes were restricted to subjects receiving at least one beta-blocker and mortality was compared between periods with and without beta-blocker exposure using Cox proportional hazard models. RESULTS: Among 14,547 survivors of myocardial infarction, 41% were dispensed at least one beta-blocker. Among those subjects, the risk of dying during periods of beta-blocker use was reduced 40% (hazard ratio = 0.6; 95% CI: 0.5, 0.7). CONCLUSION: Confounding by indication threatens the validity of observational studies of intended effects of medications. For elderly survivors of myocardial infarction, the estimated benefit of beta-blockers from observational studies is greater than the estimate from randomized trials. Greater benefits do not seem to be an artifact arising from systematically prescribing beta-blockers to subjects with better prognosis. Reducing confounding by indication can enhance the validity of observational studies of medications and widen research applications of administrative health databases. While the actual benefits of medications are never truly known these studies can provide a credible range that brackets the truth.

Bias due to aggregation of individual covariates in the Cox regression model.

The impact of covariate aggregation, well studied in relation to linear regression, is less clear in the Cox model. In this paper, the authors use real-life epidemiologic data to illustrate how aggregating individual covariate values may lead to important underestimation of the exposure effect. The issue is then systematically assessed through simulations, with six alternative covariate representations. It is shown that aggregation of important predictors results in a systematic bias toward the null in the Cox model estimate of the exposure effect, even if exposure and predictors are not correlated. The underestimation bias increases with increasing strength of the covariate effect and decreasing censoring and, for a strong predictor and moderate censoring, may exceed 20%, with less than 80% coverage of the 95% confidence interval. However, covariate aggregation always induces smaller bias than covariate omission does, even if the two phenomena are shown to be related. The impact of covariate aggregation, but not omission, is independent of the covariate-exposure correlation. Simulations involving time-dependent aggregates demonstrate that bias results from failure of the baseline covariate mean to account for nonrandom changes over time in the risk sets and suggest a simple approach that may reduce the bias if individual data are available but have to be aggregated.

Validation of diagnostic codes within medical services claims.

OBJECTIVES: Few studies have attempted to validate the diagnostic information contained within medical service claims data, and only a small proportion of these have attempted to do so using the medical chart as a gold standard. The goal of this study is to determine the sensitivity and specificity of medical services claims diagnoses for surveillance of 14 drug disease contraindications used in drug utilization review, the Charlson comorbidity index and the Johns Hopkins Adjusted Care Group Case-Mix profile (ADGs). STUDY DESIGN AND SETTING: Diagnoses were abstracted from the medical charts of 14,980 patients, and were used as the "gold standard," against which diagnoses obtained from the administrative database for the same patients were compared. RESULTS: Conditions associated with drug disease contraindications with the exception of hypertension and chronic obstructive pulmonary disease (COPD) showed a specificity of 90% or higher. Sensitivity of claims data was substantially lower, with glaucoma, hypertension, and diabetes being the most sensitive conditions at 76, 69, and 64%, respectively. Each of the 18 disease conditions contained in the Charlson comorbidity index showed high specificity, but sensitivity was more variable among conditions as well as by coding definitions. Although ADG specificity was also high, the vast majority of ADGs had sensitivities of less than 60%. CONCLUSION: The administrative data was found to have diagnoses and conditions that were highly specific but that vary greatly by condition in terms of sensitivity. To appropriately obtain diagnostic profiles, it is recommended that data pertaining to all physician billings be used.

The effect of physicians' training on prescribing beta-blockers for secondary prevention of myocardial infarction in the elderly.

PURPOSE: The objective was to determine whether the year and medical school of graduation, the medical specialty and the sex of the treating physician was associated with prescribing beta-blockers after hospital discharge among survivors of myocardial infarction (MI), after adjusting for patient characteristics. METHODS: We carried out a dynamic retrospective cohort study using data from a longitudinal database that contained information on Quebec residents over the age of 65 years sent home from hospital after MI between 1990 and 1993. The outcome was a beta-blocker being dispensed after hospital discharge. Logistic regression was used to estimate the association between training characteristics and beta-blocker dispensation and clustering of patients within physicians was accounted for using Generalized Estimating Equations. RESULTS: The cohort consisted of 14,334 MI survivors who were treated by 3209 physicians, yielding a mean of about 4.5 patients per physician [standard deviation (SD) = 8.2]. Beta-blockers were prescribed to approximately one-third of subjects. After adjusting for patients' demographic characteristics, comorbid medical conditions, and markers of MI severity, physicians who were more likely to prescribe a beta-blocker included cardiologists and the most recent graduates (graduating after 1989). Systematic differences were also observed between graduates of different medical schools. CONCLUSIONS: After adjusting for differences between patients', the sex of the physician was largely unrelated to prescribing beta-blockers for secondary prevention of MI. However, prescribing differed by training characteristics such as medical specialty and year and medical school of graduation.