Deaths from heart failure: using coarsened exact matching to correct cause-of-death statistics

<p>Abstract</p> <p>Background</p> <p>Incomplete information on death certificates makes recorded cause-of-death data less useful for public health monitoring and planning. Certifying physicians sometimes list only the mode of death without indicating the underlying disease or diseases that led to the death. Inconsistent cause-of-death assignment among cardiovascular causes of death is of particular concern. This can prevent valid epidemiologic comparisons across countries and over time.</p> <p>Methods</p> <p>We propose that coarsened exact matching be used to infer the underlying causes of death where only the mode of death is known. We focus on the case of heart failure in US, Mexican, and Brazilian death records.</p> <p>Results</p> <p>Redistribution algorithms derived using this method assign the largest proportion of heart failure deaths to ischemic heart disease in all three countries (53%, 26%, and 22% respectively), with larger proportions assigned to hypertensive heart disease and diabetes in Mexico and Brazil (16% and 23% vs. 7% for hypertensive heart disease, and 13% and 9% vs. 6% for diabetes). Reassigning these heart failure deaths increases the US ischemic heart disease mortality rate by 6%.</p> <p>Conclusions</p> <p>The frequency with which physicians list heart failure in the causal chain for various underlying causes of death allows for inference about how physicians use heart failure on the death certificate in different settings. This easy-to-use method has the potential to reduce bias and increase comparability in cause-of-death data, thereby improving the public health utility of death records.</p

Current trends in the cardiovascular clinical trial arena (I)

The existence of effective therapies for most cardiovascular disease states, coupled with increased requirements that potential benefits of new drugs be evaluated on clinical rather than surrogate endpoints, makes it increasingly difficult to substantiate any incremental improvements in efficacy that these new drugs might offer. Compounding the problem is the highly controversial issue of comparing new agents with placebos rather than active pharmaceuticals in drug efficacy trials. Despite the recent consensus that placebos may be used ethically in well-defined, justifiable circumstances, the problem persists, in part because of increased scrutiny by ethics committees but also because of considerable lingering disagreement regarding the propriety and scientific value of placebo-controlled trials (and trials of antihypertensive drugs in particular). The disagreement also substantially affects the most viable alternative to placebo-controlled trials: actively controlled equivalence/noninferiority trials. To a great extent, this situation was prompted by numerous previous trials of this type that were marked by fundamental methodological flaws and consequent false claims, inconsistencies, and potential harm to patients. As the development and use of generic drugs continue to escalate, along with concurrent pressure to control medical costs by substituting less-expensive therapies for established ones, any claim that a new drug, intervention, or therapy is "equivalent" to another should not be accepted without close scrutiny. Adherence to proper methods in conducting studies of equivalence will help investigators to avoid false claims and inconsistencies. These matters will be addressed in the third article of this three-part series

Culture and management control interdependence: An analysis of control choices that complement the delegation of authority in Western cultural regions

This study examines the influence of cultural regions on the interdependence between delegation of authority and other management control (MC) practices. In particular, we assess whether one of the central contentions of agency theory, that incentive contracting and delegation are jointly determined, holds in different cultural regions. Drawing on prior literature, we hypothesise that the MC practices that operate as a complement to delegation vary depending on societal values and preferences, and that MC practices other than incentive contracting will complement delegation in firms in non-Anglo cultural regions. Using data collected from 584 strategic business units across three Western cultural regions (Anglo, Germanic, Nordic), our results show that the interdependence between delegation and incentive contracting is confined to Anglo firms. In the Nordic and Germanic regions, we find that strategic and action planning participation operate as a complement to delegation, while delegation is also complemented by manager selection in Nordic firms. Overall, our study demonstrates that cultural values and preferences significantly influence MC interdependence, and suggests that caution needs to be taken in making cross-cultural generalisations about the complementarity of MC practices

Impact of housing on the survival of persons with AIDS

<p>Abstract</p> <p>Background</p> <p>Homeless persons with HIV/AIDS have greater morbidity and mortality, more hospitalizations, less use of antiretroviral therapy, and worse medication adherence than HIV-infected persons who are stably housed. We examined the effect of homelessness on the mortality of persons with AIDS and measured the effect of supportive housing on AIDS survival.</p> <p>Methods</p> <p>The San Francisco AIDS registry was used to identify homeless and housed persons who were diagnosed with AIDS between 1996 and 2006. The registry was computer-matched with a housing database of homeless persons who received housing after their AIDS diagnosis. The Kaplan-Meier product limit method was used to compare survival between persons who were homeless at AIDS diagnosis and those who were housed. Proportional hazards models were used to estimate the independent effects of homelessness and supportive housing on survival after AIDS diagnosis.</p> <p>Results</p> <p>Of the 6,558 AIDS cases, 9.8% were homeless at diagnosis. Sixty-seven percent of the persons who were homeless survived five years compared with 81% of those who were housed (p < 0.0001). Homelessness increased the risk of death (adjusted relative hazard [RH] 1.20; 95% confidence limits [CL] 1.03, 1.41). Homeless persons with AIDS who obtained supportive housing had a lower risk of death than those who did not (adjusted RH 0.20; 95% CL 0.05, 0.81).</p> <p>Conclusion</p> <p>Supportive housing ameliorates the negative effect of homelessness on survival with AIDS.</p