Large-scale Morbidity Research Articles

Response to Abraham

More than 4000 patients have been evaluated in randomized controlled trials of cardiac resynchronization therapy (CRT). These studies have demonstrated that CRT with or without an implantable cardioverter-defibrillator (ICD) consistently improves quality of life, functional status, exercise capacity, and cardiac structure and function and reduces morbidity and mortality in heart failure patients with ventricular dyssynchrony. The magnitude of benefit seen with CRT is comparable to or exceeds that seen with evidence-based drug therapies for heart failure but occurs in patients who are already receiving such medications. Thus, CRT has been added to the list of evidence-based therapies that make heart failure patients feel better and live longer (the Table). Consequently, a strong ethical mandate exists for the use of CRT in heart failure. This mandate is reflected in our current practice guidelines for the management of chronic heart failure, which state that all eligible patients should receive CRT unless contraindicated.1,2 End of debate! CRT should be a routine part of any evidence-based treatment regimen for heart failure. View this table: Major Benefits of Evidence-Based Heart Failure Therapies Of course, things are never quite so simple, so let us take a look at the evidence supporting this clinical mandate for CRT and address patient selection, some of the limitations of CRT, and some of the unanswered questions about the use of CRT in heart failure. None of this discussion will lessen the role of CRT in the treatment of heart failure; rather, it will guide the selection of appropriate patients and speculate on the future application of CRT to an even broader group of heart failure patients. Response by Greenberg and Mehra p 2698 Approximately one third of patients with systolic heart failure exhibit ventricular dyssynchrony, defined as a QRS duration >120 ms on the surface ECG.3,4 Ventricular dyssynchrony produces suboptimal ventricular …

Costs and benefits of a second measles inoculation of children in Israel, the West Bank, and Gaza.

Measles has been targeted by the WHO as a disease which should be eradicated. Use of existing vaccines during infancy has resulted in a substantial decline in cases in Israel, the West Bank, and Gaza. However the disease continues to occur in epidemic waves with large scale morbidity and mortality in all of these populations. This paper estimates the costs and benefits of three alternative strategies of adding immunisation at school age, and during young adult life to the present vaccination at 15 months. A policy of immunising all Israeli children aged 6 (option A) would cost around $1 million and have estimated benefits of $4.5 million, yielding a benefit cost ratio of 4.53/1. Despite relatively lower medical care costs and work absence costs (as a result of the lower per capita GNP and lower female participation rate in the workforce), the West Bank and Gaza situations yield benefit to cost ratios of 5.74/1 and 9.59/1 respectively because of their relatively higher incidence rates. If implemented in Israel, a vaccination programme (such as option A) would prevent, over the next 10 years, approximately 28,700 simple cases, 3400 hospital admissions, eight non-fatal cases of encephalitis, and 2.2 cases of SSPE. It would save 28 lives. The adoption of option A, is expected to reduce incidence and mortality by around 13,600 and 32 cases in the West Bank, and by 18,000 and 64 cases in Gaza. The adoption of a two dose policy appears to be economically justifiable.

Health effects of environmental exposure to cadmium: objectives, design and organization of the cadmibel study: a cross-sectional morbidity study carried out in Belgium from 1985 to 1989

Cadmium is a cumulative environmental pollutant. For the general population mainly exposed by the oral route and through tobacco smoke inhalation, the kidney is the critical organ. Belgium is the principal producer of cadmium in Europe, and certain areas of the country are polluted by cadmium mainly because of past emissions from nonferrous industries. Preliminary studies carried out in one polluted area have suggested that environmental pollution might lead to an increased uptake of cadmium by the human body and possibly to health effects. Thus, a large-scale morbidity study has been initiated to assess the validity of this hypothesis. The present paper describes the protocol of this study. Its main objectives are to determine to what extent environmental exposure to cadmium resulting from industrial emissions may lead to accumulation of the metal in the human organism; to establish whether or not environmental exposure may induce renal changes and/or influence blood pressure; and to assess the acceptable internal dose of cadmium for the general population. The study design takes advantage of the fact that biological indicators of exposure, body burden, and early nephrotoxic effects of cadmium are available, which increase the likelihood of detecting a cause-effect relationship.

Wildlife diseases in South Africa : a review.

The first category includes endemic African diseases which have evolved with and cycle in the various indigenous wildlife populations which, in turn, act as sylvatic reservoirs of the infectious agents. These diseases usually cause only minimal debility or mortality in indigenous wildlife and the infections are often subclinical. In contrast, infection of domestic livestock with these agents usually results in high morbidity and variable mortality. They are thus of considerable agricultural economic importance. African swine fever, African horse sickness, foot and mouth disease (SA T virus types), bovine malignant catarrh, bluetongue, Rift Valley fever, trypanosomiasis and theileriosis are good examples of this disease category. The second category includes exotic diseases which have been, or are suspected of having been introduced onto the African continent (by domestic animals). These diseases are capable of infecting certain species of indigenous wildlife, often causing large-scale morbidity and mortality. Rinderpest, rabies, anthrax and brucellosis are good examples of this category. This paper reviews our present knowledge and the current status of such diseases in South Africa.

Application of a pilot study to the development of an industrial hygiene sampling strategy.

An industrial hygiene pilot study was conducted to estimate the concentrations of respirable dust likely to be encountered during the personal sampling phase of a large-scale morbidity study of the portland cement industry. An analysis of the pilot study data showed little variability in exposure for subjects working in the same job in the same area of the same plant. Thus, one could estimate mean exposure by sampling several subjects rather than sampling the same subject several times. It was concluded that for statistical considerations, the best approach would be to sample four jobs per area and six subjects per job. Practical considerations required one more often to select six jobs with two subjects per job, however. Overall, the collection of fewer samples was required during the morbidity study than was anticipated originally. In turn, the reduction in the number of samples to be collected resulted in a savings of time and resources.

Longitudinal records of anxiety and depression in general practice: the Second National Morbidity Survey.

This paper analyses patterns of episodes of anxiety and depression as recorded by 22 general practices which took part in the Second National Morbidity Survey (RCGP, 1980). The data comprise 6 years' records. Simple Markov chains are fitted to each age-group of men and women, and the inter-practice variation in the resulting parameter estimates are compared, using Andrews' plots and principal components plots. The implications for the presentation and interpretation of data from large-scale morbidity surveys are discussed.

Prevalence of essential tremor. Results from the Copiah County study.

This investigation determined the prevalence of essential tremor in a US population. The findings were derived from a large-scale morbidity survey conducted in a rural, biracial Mississippi county (Copiah County). Both the household and the institutionalized populations of the county were included. Results were limited to persons 40 years old or older. Prevalence ratios were higher for women than for men and were higher for whites than for blacks. Age-specific prevalence ratios generally increased with age. The overall prevalence ratio was 414.6 per 100,000 inhabitants.