M.A.L.M. van Assen

The prediction of disability by self-reported physical frailty components of the Tilburg Frailty Indicator (TFI)

Disability is an important health outcome for older persons; it is associated with impaired quality of life, future hospitalization, and mortality. Disability also places a high burden on health care professionals and health care systems. Disability is regarded as an adverse outcome of physical frailty. The main objective of this study was to assess the predictive validity of the eight individual self-reported components of the physical frailty subscale of the TFI for activities of daily living (ADL) and instrumental activities of daily living (IADL) disability. This longitudinal study was carried out with a sample of Dutch citizens. At baseline the sample consisted at 429 people aged 65 years and older and a subset of all respondents participated again two and a half years later (N=355, 83% response rate). The respondents completed a web-based questionnaire comprising the TFI and the Groningen Activity Restriction Scale (GARS) for measuring disability. Five components together (unintentional weakness, weakness, poor endurance, slowness, low physical activity), referring to the phenotype of Fried et al., predicted disability, even after controlling for previous disability and other background characteristics. The other three components of the physical frailty subscale of the TFI (poor balance, poor hearing, poor vision) together did not predict disability. Low physical activity predicted both total and ADL disability, and slowness both total and IADL disability. In conclusion, self-report assessment using the physical subscale of the TFI aids the prediction of future ADL and IADL disability in older persons two and a half years later.

Profiles of individually defined recovery of people with major psychiatric problems

Background: Research on factors associated with individually defined recovery is limited. Several phases of recovery have been described in the literature. Individuals in these distinct phases have different characteristics and problems. Aims: To identify classes of people with major psychiatric problems who have comparable profiles of individually defined recovery, to relate these classes to the phases of recovery as described by Spaniol, Wewiorsky, Gagne, and Anthony (2002), and to associate the classes to demographic and psychiatric characteristics, and health-related variables. Methods: Data of 333 participants with major psychiatric problems were used. A latent class analysis was conducted on the mean scores of four proxy measures of recovery. Results: Three well-defined classes were found that differed on the recovery measures. The classes differed significantly on variables corresponding to Spaniol’s phases of recovery (Spaniol et al., 2002) and on health care utilization, health care needs and anxiety disorder, but not on demographic variables. Conclusions: It is possible to identify classes of people with major psychiatric problems who have comparable profiles of individually defined recovery that seem to correspond to phases of recovery. More knowledge of the characteristics of people in different phases of recovery will contribute to more fine-tuned and recovery-oriented health care.

Dynamic exchange networks

Considering the theoretical and empirical untenability of static exchange networks, researchers have asked how exchange outcomes change when links are added or deleted. The present paper assesses the validity of seemingly sensible propositions concerning the effects of adding and deleting a link on (i) the payoffs of the actors in the link, (ii) the payoffs of actors in neighboring links and (iii) the variance of payoffs in the exchange network. The propositions were examined by applying expected value theory (EVT) to all 13,597 networks up to size 8. All propositions were falsified. Some falsifications of propositions could be attributed to EVTs prediction that actors use sub-optimal exchange relations. Since other well-known theories of exchange, like power-dependence theory and network exchange theory, also predict that actors use sub-optimal relations, these results are robust to selection of the theory of exchange.

Fragiliteit bij jonge ouderen: meting met de Tilburg Frailty Indicator

BACKGROUND Frail elderly have a higher risk of adverse outcomes, e.g., hospitalization,institutionalization, or premature death. The Tilburg Frailty Indicator (TFI) is a validated questionnaire for measuring frailty in independently living older people aged 70 years and over. AIMS Determining the prevalence of frailty among independently living young elderly, and examining which factors predict frailty among this target group. METHODS 308 young elderly (58 to 64 years) completed the TFI before they visited the ambulatory health screening centre in Roosendaal. The TFI includes questions concerning physical, psychological and social frailty, and questions on possible determinants of frailty. RESULTS 18-4% of the sample of young elderly was frail. Women scored significantly higher on psychological and social frailty. The determinants explained 37% of the frailty score. As expected,low income, an unhealthy lifestyle, multimorbidity, experiencing life events, and dissatisfaction with the living environment predicted frailty. The three frailty domains(physical, psychological, social) were affected by different determinants. CONCLUSION A substantial part of the young elderly in the sample turned out to be frail. The finding that the three domains of frailty are predicted by different determinants underlines the importance the importance of a broad perspective regarding the functioning of the individual older person.

Stability of Exchange Networks

This paper develops a formal model of exchange network stability that combines expected value theory (Friedkin 1995) with the economic literature on network dynamics. We identify stable networks up to size 8 for varying costs and investigate whether they are Pareto efficient and egalitarian. Only a very small number of networks are stable. Odd cycles and networks consisting of dyads and at most one isolate are the only egalitarian, efficient, and stable networks for a large cost range. We show that some of these results are generalizable to networks of any size and are independent of using expected value theory.