Long-term health outcomes and cost-effectiveness of a computer-tailored physical activity intervention among people aged over fifty:modelling the results of a randomized controlled trial

Background: Physical inactivity is a significant predictor of several chronic diseases, becoming more prevalent as people age. Since the aging population increases demands on healthcare budgets, effectively stimulating physical activity (PA) against acceptable costs is of major relevance. This study provides insight into long-term health outcomes and cost-effectiveness of a tailored PA intervention among adults aged over fifty. Methods: Intervention participants (N= 1729) received tailored advice three times within four months, targeting the psychosocial determinants of PA. The intervention was delivered in different conditions (i.e. print delivered versus Web based, and with or without additional information on local PA opportunities). In a clustered RCT, the effects of the different intervention conditions were compared to each other and to a control group. Effects on weekly Metabolic Equivalents (MET) hours of PA obtained one year after the intervention started were extrapolated to long-term outcomes (5 year, 10 year and lifetime horizons) in terms of health effects and quality-adjusted life years (OALYs) and its effect on healthcare costs, using a computer simulation model. Combining the model outcomes with intervention cost estimates, this study provides insight into the long-term cost-effectiveness of the intervention. Incremental cost-effectiveness ratios (ICERs) were calculated. Results: For all extrapolated time horizons, the printed and the Web based intervention resulted in decreased incidence numbers for diabetes, colon cancer, breast cancer, acute myocardial infarctions, and stroke and increased QALYs as a result of increased PA. Considering a societal Willingness-to-Pay of 20,000/QALY, on a lifetime horizon the printed (ICER =E7,500/QALY) as well as the Web based interventions (ICER = E10,100/QALY) were cost-eftective. On a 5-year time horizon, the Web based intervention was preferred over the printed intervention. On a 10 year and lifetime horizon, the printed intervention was the preferred intervention condition, since the monetary savings of the Web based intervention did no longer outweigh its lower effects. Adding environmental information resulted in a lower cost-effectiveness. Conclusion: A tailored PA intervention in a printed delivery mode, without environmental information, has the most potential for being cost-effective in adults aged over 50

Motivational factors for initiating and maintaining physical activity among adults aged over fifty targeted by a tailored intervention

Objective: To provide insight into the motivational working mechanisms (i.e. mediators) of an effective physical activity (PA) intervention for adults aged over fifty. Design: The mediation model (N = 822) was investigated in an RCT for the total intervention population, participants who were not norm-active at baseline (targeting PA initiation) and norm-active participants (targeting PA maintenance) separately. Main Outcome Measures: Potential mediators (attitude, self-efficacy, intention, action planning and coping planning) of the effect on PA (6-months) were assessed at baseline, 3 and/or 6 months. Results: The intervention resulted in a decrease in intention (B= −.209; p=.017), and an increase in action planning (B=.214; p=.018) and PA (B=.220; p=.002). Intention and action planning did not mediate the effect on PA. Self-efficacy, although not significantly influenced by the intervention, was found to be the only motivational variable that predicted change in PA (B=.164; p=.007). These results were confirmed among participants initiating PA. Among norm-active participants no significant intervention effects were identified. Conclusion: The motivational factors cannot explain the intervention effect on PA. Most likely, the effect can be explained by an interaction between the motivational factors together. Differences between participants initiating versus maintaining PA, highlight the importance of performing mediation analyses per subgroup

Modeling Longitudinal Relationships Between Habit and Physical Activity: Two Cross-Lagged Panel Design Studies in Older Adults

These longitudinal studies in older adults targeted mediated relationships between habit and physical activity (PA). In The Netherlands two independent studies were conducted among 1976 (Study 1: Mage=63.63, SD=8.66, 30% functional limitations) and 2140 (Study 2: Mage=62.75, SD=8.57, 45% functional limitations) adults aged 50 years or older. Cross-lagged panel designs were applied to examine whether habit mediates the relationship between prior and later PA and whether PA simultaneously mediates the relationship between prior and later habit. Data on habit and PA were collected by means of questionnaires at baseline (t0) and at six (t1) and twelve (t2) months after baseline measurement. Results of structural equation modeling analyses were not unambiguous. Indications for the existence of both hypothesized mediation effects were found, but no clear, unequivocal pattern appeared. Somewhat more support was found for the PA-habit-PA path than for the habit-PA-habit path. More research is needed to draw more definitive conclusions

Predictive Modeling to Study the Treatment-Shortening Potential of Novel Tuberculosis Drug Regimens, Toward Bundling of Preclinical Data

Background Given the persistently high global burden of tuberculosis, effective and shorter treatment options are needed. We explored the relationship between relapse and treatment length as well as interregimen differences for 2 novel antituberculosis drug regimens using a mouse model of tuberculosis infection and mathematical modeling. Methods Mycobacterium tuberculosis-infected mice were treated for up to 13 weeks with bedaquiline and pretomanid combined with moxifloxacin and pyrazinamide (BPaMZ) or linezolid (BPaL). Cure rates were evaluated 12 weeks after treatment completion. The standard regimen of isoniazid, rifampicin, pyrazinamide, and ethambutol (HRZE) was evaluated as a comparator. Results Six weeks of BPaMZ was sufficient to achieve cure in all mice. In contrast, 13 weeks of BPaL and 24 weeks of HRZE did not achieve 100% cure rates. Based on mathematical model predictions, 95% probability of cure was predicted to occur at 1.6, 4.3, and 7.9 months for BPaMZ, BPaL, and HRZE, respectively. Conclusion This study provides additional evidence for the treatment-shortening capacity of BPaMZ over BPaL and HRZE. To optimally use preclinical data for predicting clinical outcomes, and to overcome the limitations that hamper such extrapolation, we advocate bundling of available published preclinical data into mathematical models. By combining the evaluation of treatment efficacy of anti-tuberculosis drug regimens in a mouse tuberculosis infection model with mathematical modeling, it was found that BPaMZ had a higher treatment-shortening potential than BPaL, compared to the standard HRZE regimen

Effectiveness of two intensive treatment methods for smoking cessation and relapse prevention in patients with coronary heart disease: study protocol and baseline description

Contains fulltext : 111068.pdf (publisher's version ) (Open Access)BACKGROUND: There is no more effective intervention for secondary prevention of coronary heart disease than smoking cessation. Yet, evidence about the (cost-)effectiveness of smoking cessation treatment methods for cardiac inpatients that also suit nursing practice is scarce. This protocol describes the design of a study on the (cost-)effectiveness of two intensive smoking cessation interventions for hospitalised cardiac patients as well as first results on the inclusion rates and the characteristics of the study population. METHODS/DESIGN: An experimental study design is used in eight cardiac wards of hospitals throughout the Netherlands to assess the (cost-)effectiveness of two intensive smoking cessation counselling methods both combined with nicotine replacement therapy. Randomization is conducted at the ward level (cross-over). Baseline and follow-up measurements after six and 12 months are obtained. Upon admission to the cardiac ward, nurses assess patients' smoking behaviour, ensure a quit advice and subsequently refer patients for either telephone counselling or face-to-face counselling. The counselling interventions have a comparable structure and content but differ in provider and delivery method, and in duration. Both counselling interventions are compared with a control group receiving no additional treatment beyond the usual care. Between December 2009 and June 2011, 245 cardiac patients who smoked prior to hospitalisation were included in the usual care group, 223 in the telephone counselling group and 157 in the face-to-face counselling group. Patients are predominantly male and have a mean age of 57 years. Acute coronary syndrome is the most frequently reported admission diagnosis. The ultimate goal of the study is to assess the effects of the interventions on smoking abstinence and their cost-effectiveness. Telephone counselling is expected to be more (cost-)effective in highly motivated patients and patients with high SES, whereas face-to-face counselling is expected to be more (cost-)effective in less motivated patients and patients with low SES. DISCUSSION: This study examines two intensive smoking cessation interventions for cardiac patients using a multi-centre trial with eight cardiac wards. Although not all eligible patients could be included and the distribution of patients is skewed in the different groups, the results will be able to provide valuable insight into effects and costs of counselling interventions varying in delivery mode and intensity, also concerning subgroups. TRIAL REGISTRATION: Dutch Trial Register NTR2144