Going Beyond the Visible in Type 2 Diabetes Mellitus: Defense Mechanisms and Their Associations With Depression and Health-Related Quality of Life

This article reports on the development and validation of the Italian SF-36 Health Survey using data from seven studies in which an Italian version of the SF-36 was administered to more than 7000 subjects between 1991 and 1995. Empirical findings from a wide array of studies and diseases indicate that the performance of the questionnaire improved as the Italian translation was revised and that it met the standards suggested by the literature in terms of feasibility, psychometric tests, and interpretability. This generally satisfactory picture strengthens the idea that the Italian SF-36 is as valid and reliable as the original instrument and applicable and valid across age, gender, and disease. Empirical evidence from a cross-sectional survey carried out to norm the final version in a representative sample of 2031 individuals confirms the questionnaire's characteristics in terms of hypothesized constructs and psychometric behavior and gives a better picture of its external validity (i.e., robustness and generalizability) when administered in settings that are very close to real world.

According to the World Health Organization, approximately 220 million people worldwide have type 2 diabetes mellitus. Patients with type 2 diabetes not only have a chronic disease to cope with, they are also at increased risk for coronary heart disease, peripheral vascular disease, retinopathy, nephropathy, and neuropathy. The exact causes of type 2 diabetes are still not clear. Since the 17th century, it has been suggested that emotional stress plays a role in the etiology of type 2 diabetes mellitus. So far, review studies have mainly focused on depression as a risk factor for the development of type 2 diabetes mellitus. Yet, chronic emotional stress is an established risk factor for the development of depression. The present review provides an overview of mainly prospective epidemiological studies that have investigated the associations between different forms of emotional stress and the development of type 2 diabetes mellitus. Results of longitudinal studies suggest that not only depression but also general emotional stress and anxiety, sleeping problems, anger, and hostility are associated with an increased risk for the development of type 2 diabetes. Conflicting results were found regarding childhood neglect, life events, and work stress. It is important to emphasize that publication-bias may have occurred, resulting from "fishing-expeditions," where authors search their data for significant associations. Publication bias may also be caused by the tendency of reviewers and Editors to reject manuscripts with negative results for publication. It is therefore essential that research groups, who aim to conduct a new epidemiological cohort study, prospectively describe and publish the design of their study. Future research should focus on identifying mechanisms linking different forms of stress and incident type 2 diabetes.

'Clinimetrics' is the term introduced by Alvan R. Feinstein in the early 1980s to indicate a domain concerned with indexes, rating scales and other expressions that are used to describe or measure symptoms, physical signs and other clinical phenomena. Clinimetrics has a set of rules that govern the structure of indexes, the choice of component variables, the evaluation of consistency, validity and responsiveness. This review illustrates how clinimetrics may help expanding the narrow range of information that is currently used in clinical science. It will focus on characteristics and types of clinimetric indexes and their current use. The clinimetric perspective provides an intellectual home for clinical judgment, whose implementation is likely to improve outcomes both in clinical research and practice.