Developing a fall prevention intervention economic model.

PURPOSE: Model-based economic evaluations require conceptualization of the model structure. Our objectives were to identify important health states, events, and patient attributes to be included in a model-based cost-effectiveness analysis of fall prevention interventions, to develop a model structure to examine cost-effectiveness of fall prevention interventions, and to assess the face validity of the model structure. METHODS: An expert panel comprising clinicians, health service researchers, health economists, a patient partner, and policy makers completed two rounds of online surveys to gain consensus on health states, events, and patient attributes important for fall prevention interventions. The surveys were informed by a literature search on fall prevention interventions for older adults (≥65 years) including economic evaluations and clinical practice guidelines. The results of the Delphi surveys and subsequent discussions can support the face validity of a state-transition model for an economic evaluation of fall prevention interventions. RESULTS: In total, 11 experts rated 24 health states/events and 41 patient attributes. Consensus was achieved on 14 health states/events and 26 patient characteristics. The proposed model structure incorporated 12 of the 14 selected health states/events. Panelists confirmed the face validity of the model structure during teleconferences. CONCLUSIONS: There is a dearth of studies presenting the model conceptualization process; consequently, this study involving multiple end user partners with opportunities for input at several stages adds to the literature as another case study. This process is an example of how a fall prevention economic model was developed using a modified Delphi process and assessed for face validity.

Factors associated with screening positive for high falls risk in fragility fracture patients: a cross-sectional study.

BACKGROUND: We sought to report the prevalence of fragility fracture patients who were screened at high falls risk using a large provincial database, and to determine the characteristics associated with being screened at high falls risk. METHODS: The study population included fragility fracture patients 50+ years of age who were screened at 35 hospital fracture clinics in Ontario over a 3.5 year period. The outcome was based on two screening questions measuring the risk of falling, both adapted from the STEADI (Stopping Elderly Accidents, Deaths & Injuries) tool. Multivariable associations of sociodemographic, fracture-related, and health-related characteristics were evaluated using logistic regression. RESULTS: Of the sample, 9735 (44.5%) patients were classified as being at high falls risk, and 12,089 (55.3%) were not. In the multivariable logistic regression, being 80+ years of age (vs. 50-64 years of age), non-community dwelling (vs. living with spouse, family member, roommate), having a mental/physical impairment (vs. none), and taking multiple medications, were all strongly associated with being screened at high falls risk. CONCLUSIONS: Living in a non-community dwelling and taking 4+ medications were the variables most strongly associated with being screened at high falls risk. These are potentially modifiable characteristics that should be considered when assessing falls risk in fragility fracture patients, and particularly when designing interventions for preventing subsequent falls. Ongoing work to address the higher risk of falls in the fragility fracture population is warranted.

Correlations between arsenic in Maine groundwater and microbial populations as determined by fluorescence in situ hybridization.

Arsenic is known to cause serious health effects when consumed in drinking water. In the state of Maine, approximately half of the population relies on private groundwater wells for their drinking water. Of those wells, as many as 13% may contain arsenic levels above the current EPA maximum contaminant level of 10 microgl(-1). Microorganisms can potentially contribute to arsenic release into groundwater through several mechanisms. Some can reduce arsenate to arsenite, which is more toxic and may be more mobile. Sulfurospirillum species NP4, which was isolated from well water, respires arsenate and could act in this way. Microorganisms can also act indirectly by reducing bedrock surface coatings, such as iron oxyhydroxides, that adsorb arsenic in the groundwater environment. The genus Geobacter contains many species that are capable of iron reduction that could play a role in the indirect release of arsenic into groundwater. Water samples from Northport, ME and the Branch Lake region of Ellsworth, ME, which both have elevated groundwater arsenic levels, have been probed using fluorescence in situ hybridization (FISH), to determine the percentage of the population that is NP4 and the percentage that are Geobacter species. Geobacter abundance correlates well with the total arsenic concentration indicating that indirect mechanisms could be important in releasing arsenic. NP4 appears to be reducing arsenate since its prevalence correlates well with arsenite, the end product of arsenate respiration.