Lee Carter mortality forecasting: application to the Italian population

In this paper we investigate the feasibility of using the Lee-Carter methodology to construct mortality forecasts for the Italian population. We fit the model to the matrix of Italian death rates for each gender from 1950 to 2000. A time-varying index of mortality is forecasted in an ARIMA framework and is used to generate projected life tables. In particular we focus on life expectancies at birth and, for the purpose of comparison, we introduce an alternative approach for forecasting life expectancies on a period basis. The resulting forecasts generated by the two methods are then compared

Coherent modeling of mortality patterns for age-specific subgroups

The recent actuarial literature has shown that mortality patterns and trajectories in closely related populations are similar in some respects and that small differences are unlikely to increase in the long run. The common feeling is that mortality forecasts for individual countries could be improved by taking into account the patterns from a larger group. Starting from this consideration, we apply the three-way Lee–Carter model to a group of countries, by extending the bilinear LC model to a three-way structure, which incorporates a further component in the decomposition of the log-mortality rates. From a methodological point of view, there are several issues to deal with when focusing on such kind of data. In the presence of a three-way data structure, several choices on the pretreatment of the data could affect the whole modeling process. This kind of analysis is useful to assess the source of variation in the raw mortality data, before the extraction of the rank-one components by the LC model. The proposed procedure is used to extract an ad hoc time mortality trend parameter for age-specific subgroups. The results show that the proposed strategy leads to a more coherent description of mortality for age-specific subgroups

The Poisson Log-Bilinear Lee-Carter Model: Applications Of efficient bootstrap methods to annuity analyses

Life insurance companies deal with two fundamental types of risks when issuing annuity contracts: financial risk and demographic risk. Recent work on the latter has focused on modeling the trend in mortality as a stochastic process. A popular method for modeling death rates is the Lee-Carter model. This methodology has become widely used, and various extensions and modifications have been proposed to obtain a broader interpretation and to capture the main features of the dynamics of mortality rates. In order to improve the measurement of uncertainty in survival probability estimates, in particular for older ages, the paper proposes an extension based on simulation procedures and on the bootstrap methodology. It aims to obtain more reliable and accurate mortality projections, based on the idea of obtaining an acceptable accuracy of the estimate by means of variance reducing techniques. In this way the forecasting procedure becomes more efficient. The longevity question constitutes a critical element in the solvency appraisal of pension annuities. The demographic models used for the cash flow distributions in a portfolio impact on the mathematical reserve and surplus calculations and affect the risk management choices for a pension plan. The paper extends the investigation of the impact of survival uncertainty for life annuity portfolios and for a guaranteed annuity option in the case where interest rates are stochastic. In a framework in which insurance companies need to use internal models for risk management purposes and for determining their solvency capital requirement, the authors consider the surplus value, calculated as the ratio between the market value of the projected assets to that of the liabilities, as a meaningful measure of the company's financial position, expressing the degree to which the liabilities are covered by the assets

Detecting Common Longevity Trends by a Multiple Population Approach

Recently the interest in the development of country and longevity risk models has been growing. The investigation of long-run equilibrium relationships could provide valuable information about the factors driving changes in mortality, in particular across ages and across countries. In order to investigate cross-country common longevity trends, tools to quantify, compare, and model the strength of dependence become essential. On one hand, it is necessary to take into account either the dependence for adjacent age groups or the dependence structure across time in a single population setting-a sort of intradependence structure. On the other hand, the dependence across multiple populations, which we describe as interdependence, can be explored for capturing common long-run relationships between countries. The objective of our work is to produce longevity projections by taking into account the presence of various forms of cross-sectional and temporal dependencies in the error processes of multiple populations, considering mortality data from different countries. The algorithm that we propose combines model-based predictions in the Lee-Carter (LC) framework with a bootstrap procedure for dependent data, and so both the historical parametric structure and the intragroup error correlation structure are preserved. We introduce a model which applies a sieve bootstrap to the residuals of the LC model and is able to reproduce, in the sampling, the dependence structure of the data under consideration. In the current article, the algorithm that we build is applied to a pool of populations by using ideas from panel data; we refer to this new algorithm as the Multiple Lee-Carter Panel Sieve (MLCPS). We are interested in estimating the relationship between populations of similar socioeconomic conditions. The empirical results show that the MLCPS approach works well in the presence of dependence

Association of Methadone Treatment With Substance-Related Hospital Admissions Among a Population in Canada With a History of Criminal Convictions

Importance  People with criminal histories experience high rates of opioid dependence and are frequent users of acute health care services. It is unclear whether methadone adherence prevents hospitalizations. Objective  To compare hospital admissions during medicated and nonmedicated methadone periods. Design, Setting, and Participants  A retrospective cohort study involving linked population-level administrative data among individuals in British Columbia, Canada, with provincial justice contacts (n= 250 884) and who filled a methadone prescription between April 1, 2001, and March 31, 2015. Participants were followed from the date of first dispensed methadone prescription until censoring (date of death, or March 31, 2015). Data analysis was conducted from May 1 to August 31, 2018. Exposures  Methadone treatment was divided into medicated (methadone was dispensed) and nonmedicated (methadone was not dispensed) periods and analyzed as a time-varying exposure. Main Outcome and Measures  Adjusted hazard ratios (aHRs) of acute hospitalizations for any cause and cause-specific (substance use disorder [SUD], non–substance-related mental disorders [NSMDs], and medical diagnoses [MEDs]) were estimated using multivariable Cox proportional hazards regression. Results  A total of 11 401 people (mean [SD] age, 34.9 [9.4] years; 8230 [72.2%] men) met inclusion criteria and were followed up for a total of 69 279.3 person-years. During a median follow-up time of 5.5 years (interquartile range, 2.8-9.1 years), there were 19 160 acute hospital admissions. Dispensed methadone was associated with a 50% lower rate of hospitalization for any cause (aHR, 0.50; 95% CI, 0.46-0.53) during the first 2 years (≤2.0 years) following methadone initiation, demonstrating significantly lower rates of admission for SUD (aHR, 0.32; 95% CI, 0.27-0.38), NSMD (aHR, 0.41; 95% CI, 0.34-0.50), and MED (aHR, 0.57; 95% CI, 0.52-0.62). As duration of time increased (2.1 to ≤5.0 years; 5.1 to ≤10.0 years), methadone was associated with a significant but smaller magnitude of effect: SUD (aHR, 0.43; 95% CI, 0.36-0.52; aHR, 0.47; 95% CI, 0.37-0.61), NSMD (aHR, 0.51; 95% CI, 0.41-0.64; aHR, 0.60; 95% CI, 0.47-0.78), and MED (aHR, 0.71; 95% CI, 0.65-0.77; aHR, 0.85; 95% CI, 0.76-0.95). Conclusions and Relevance  In this study, methadone was associated with a lower rate of hospitalization among a large cohort of Canadian individuals with histories of convictions and prevalent concurrent health and social needs. Practices to improve methadone adherence are warranted. &nbsp

Methadone Maintenance Treatment and Mortality in People with Criminal Convictions: A Population-Based Retrospective Cohort Study from Canada

Background Individuals with criminal histories have high rates of opioid dependence and mortality. Excess mortality is largely attributable to overdose deaths. Methadone maintenance treatment (MMT) is one of the best evidence-based opioid substitution treatments (OSTs), but there is uncertainty about whether methadone treatment reduces the risk of mortality among convicted offenders over extended follow-up periods. The objective of this study was to investigate the association between adherence to MMT and overdose fatality as well as other causes of mortality. Methods and findings We conducted a retrospective cohort study involving linked population-level administrative data among individuals in British Columbia (BC), Canada with a history of conviction and who filled a methadone prescription between January 1, 1998 and March 31, 2015. Participants were followed from the date of first-dispensed methadone prescription until censoring (date of death or March 31, 2015). Methadone was divided into medicated (methadone was dispensed) and nonmedicated (methadone was not dispensed) periods and analysed as a time-varying exposure. Hazard ratios (HRs) with 95% CIs were estimated using multivariable Cox regression to examine mortality during the study period. All-cause and cause-specific mortality rates were compared during medicated and nonmedicated methadone periods. Participants (n = 14,530) had a mean age of 34.5 years, were 71.4% male, and had a median follow-up of 6.9 years. A total of 1,275 participants died during the observation period. The overall all-cause mortality rate was 11.2 per 1,000 person-years (PYs). Participants were significantly less likely to die from both nonexternal (adjusted HR [AHR] 0.27 [95% CI 0.23–0.33]) and external (AHR 0.41 [95% CI 0.33–0.51]) causes during medicated periods, independent of sociodemographic, criminological, and health-related factors. Death due to infectious diseases was 5 times lower (AHR 0.20 [95% CI 0.13–0.30]), and accidental poisoning (overdose) deaths were nearly 3 times lower (AHR 0.39 [95% CI 0.30–0.50]) during medicated periods. A competing risk regression demonstrated a similar pattern of results. The use of a Canadian offender population may limit generalizability of results. Furthermore, our observation period represents community-based methadone prescribing and may omit prescriptions administered during hospital separations. Therefore, the magnitude of the protective effects of methadone from nonexternal causes of death should be interpreted with caution. Conclusions Adherence to methadone was associated with significantly lower rates of death in a population-level cohort of Canadian convicted offenders. Achieving higher rates of adherence may reduce overdose deaths and other causes of mortality among offenders and similarly marginalized populations. Our findings warrant examination in other study centres in response to the crisis of opiate-involved deaths

Extending the Lee Carter Model: a Three-way Decomposition

In this paper, we focus on a Multidimensional Data Analysis approach to the Lee-Carter (LC) model of mortality trends . In particular, we extend the bilinear LC model and specify a new model based on a three-way structure, which incorporates a further component in the decomposition of the log-mortality rates. A multi-way component analysis is performed using the Tucker 3 model. The suggested methodology allows us to obtain combined estimates for the three modes: i) time, ii) agegroups and iii) different populations. From the results obtained by the Tucker 3 decomposition, we can jointly compare, in both a numerical and graphical way, the relationships among all three modes and obtain a time series component as a leading indicator of the mortality trend for a group of populations. Further, we carry out a correlation analysis of the estimated trends in order to assess the reliability of the results of the three-way decomposition. The model’s goodness of fit is assessed using an analysis of the residuals. Finally, we discuss how the synthesised mortality index can be used to build concise projected life tables for a group of populations. An application which compares ten European countries is used to illustrate the approach and provide a deeper insight into the model and its implementation

Efficacy of biofeedback rehabilitation based on visual evoked potentials analysis in patients with advanced age-related macular degeneration

Age-related macular degeneration (AMD) is a progressive and degenerative disorder of the macula. In advanced stages, it is characterized by the formation of areas of geographic atrophy or fibrous scars in the central macula, which determines irreversible loss of central vision. These patients can benefit from visual rehabilitation programmes with acoustic "biofeedback" mechanisms that can instruct the patient to move fixation from the central degenerated macular area to an adjacent healthy area, with a reorganization of the primary visual cortex. In this prospective, comparative, non-randomized study we evaluated the efficacy of visual rehabilitation with an innovative acoustic biofeedback training system based on visual evoked potentials (VEP) real-time examination (Retimax Vision Trainer, CSO, Florence), in a series of patients with advanced AMD compared to a control group. Patients undergoing training were subjected to ten consecutive visual training sessions of 10min each, performed twice a week. Patients in the control group did not receive any training. VEP biofeedback rehabilitation seems to improve visual acuity, reading performances, contrast sensitivity, retinal fixation and sensitivity and quality of life in AMD patients

Tranexamic acid therapy in pediatric cardiac surgery:a single center study

Background: We conducted a retrospective study of cyanotic and acyanotic patients undergoing cardiopulmonary bypass to determine the effect of tranexamic acid on blood loss and blood products administered during the operation in pediatric cardiac surgery. Methods: From January 2008 to December 2011, during 2 different periods, a total of 231 pediatric patients undergoing cardiac surgery with cardiopulmonary bypass (123 cyanotic, 108 acyanotic) were included in this study. A total of 104 patients were in the antifibrinolytic group and exclusively treated with tranexamic acid that was given as a bolus of 20 mg/kg-1 after anesthetic induction and 20 mg/kg-1 after protamine. The other 127 patients were in the control group. We analyzed intraoperative and postoperative outcomes of tranexamic acid administration. Results: There were no differences in mortality or operative time, but blood loss in 48 hours was greater in the control group (p = 0.0012). A significant difference was found in the amount of intraoperative erythrocyte concentrate transfused (140 ± 55 vs 170 ± 78 mL, p = 0.0011) but not in number. The number and amount of erythrocyte concentrate transfused in the first 48 postoperative hours were also greater in the control group (45 vs 77 patients, p = 0.012; 100 ± 40 vs 120 ± 55 mL, p = 0.0022). There were not many differences in the effect of tranexamic acid between the cyanotic and acyanotic subgroup. Conclusions: This retrospective study provides evidence that tranexamic acid may be used in the field of congenital cardiac surgery effectively

First experience with sildenafil after Fontan operation: short-term outcomes.

Background We conducted a retrospective study to determine the effect of oral sildenafil administrated as monotherapy after Fontan operation in single ventricle physiology. Methods From January 2008 to March 2012, during two different periods, a total of 30 pediatric patients undergoing Fontan operation by extracardiac conduit were included in this study. Thirteen patients were in the sildenafil group and exclusively treated with sildenafil given at the dose of 0.35 mg/kg through a nasogastric tube and then orally every 4 h, at the start of cardiopulmonary bypass and for the first postoperative week; then we reduced and discontinued the therapy. The other 17 patients were in the control group. No other vasodilator was administered in both groups. We analyzed intraoperative and postoperative outcomes of sildenafil administration. Results There were no differences in mortality or operative time. The total and relative drainage loss was lower in the sildenafil group (PU0.0003 and 0.0045). The hemodynamic parameters showed a better condition in the sildenafil group, with a lower mean pulmonary artery pressure (mPAP) (PU0.0001) and better mPAP to mean systemic blood pressure (mSBP) ratio (PU0.0043), whereas there was no difference in peripheral oxygen saturation (PU0.31). The sidenafil group patients showed other additional positive differences as well as lower inotropic score (PU0.0005) and intubation time (PU0.0004). No complications related to the use of sildenafil were noted in any of the children studied. Conclusion This initial experience provides evidence that sildenafil may be used in postoperative Fontan operation with positive effectiveness