Using Age-Specific Rates for Parametric Survival Function Estimation in Simulation Models

PURPOSE

To describe a procedure for incorporating parametric functions into individual-level simulation models to sample time to event when age-specific rates are available but not the individual data.

METHODS

Using age-specific event rates, regression analysis was used to parametrize parametric survival distributions (Weibull, Gompertz, log-normal, and log-logistic), select the best fit using the R2 statistic, and apply the corresponding formula to assign random times to events in simulation models. We used stroke rates in the Spanish population to illustrate our procedure.

RESULTS

The 3 selected survival functions (Gompertz, Weibull, and log-normal) had a good fit to the data up to 85 y of age. We selected Gompertz distribution as the best-fitting distribution due to its goodness of fit.

CONCLUSIONS

Our work provides a simple procedure for incorporating parametric risk functions into simulation models without individual-level data.

HIGHLIGHTS

We describe the procedure for sampling times to event for individual-level simulation models as a function of age from parametric survival functions when age-specific rates are available but not the individual dataWe used linear regression to estimate age-specific hazard functions, obtaining estimates of parameter uncertainty.Our approach allows incorporating parameter (second-order) uncertainty in individual-level simulation models needed for probabilistic sensitivity analysis in the absence of individual-level survival data.

GOIZ ZAINDU study: a FINGER-like multidomain lifestyle intervention feasibility randomized trial to prevent dementia in Southern Europe

BACKGROUND

GOIZ ZAINDU ("caring early" in Basque) is a pilot study to adapt the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) methodology to the Basque population and evaluate the feasibility and adherence to a FINGER-like multidomain intervention program. Additional aims included the assessment of efficacy on cognition and data collection to design a large efficacy trial.

METHOD

GOIZ ZAINDU is a 1-year, randomized, controlled trial of a multidomain intervention in persons aged 60+ years, with Cardiovascular Risk Factors, Aging and Dementia (CAIDE) risk score ≥ 6, no diagnosis of dementia, and below-than-expected performance in at least one of three cognitive screening tests. Randomization to a multidomain intervention (MD-Int) or regular health advice (RHA) was stratified by sex, age (>/≤ 75), and cognitive status (mild cognitive impairment (MCI)/normal cognition). MD-Int included cardiovascular risk factor control, nutritional counseling, physical activity, and cognitive training. The primary outcomes were retention rate and adherence to the intervention program. Exploratory cognitive outcomes included changes in the Neuropsychological Test Battery z-scores. Analyses were performed according to the intention to treat.

RESULTS

One hundred twenty-five participants were recruited (mean age: 75.64 (± 6.46); 58% women). The MD-Int (n = 61) and RHA (n = 64) groups were balanced in terms of their demographics and cognition. Fifty-two (85%) participants from the RHA group and 56 (88%) from the MD-Int group completed the study. More than 70% of the participants had high overall adherence to the intervention activities. The risk of cognitive decline was higher in the RHA group than in the MD-Int group in terms of executive function (p =.019) and processing speed scores (p =.026).

CONCLUSIONS

The GOIZ-ZAINDU study proved that the FINGER methodology is adaptable and feasible in a different socio-cultural environment. The exploratory efficacy results showed a lower risk of decline in executive function and processing speed in the intervention group. These results support the design of a large-scale efficacy trial.

TRIAL REGISTRATION

GOIZ ZAINDU feasibility trial was approved and registered by the Euskadi Drug Research Ethics Committee (ID: PI2017134) on 23 January 2018. Retrospectively registered in ClinicalTrials.gov (NCT06163716) on 8 December 2023.

Effectiveness of the booster dose of COVID-19 vaccine in the Basque Country during the sixth wave: A nationwide cohort study

The aim of the study was to assess the effect of a booster dose of COVID-19 vaccine on the rates of hospital ward and intensive care unit (ICU) admissions around the time of emergence of the Omicron variant in the Basque Country. A retrospective cohort population-based study was conducted. The population with any records related to COVID-19 vaccination up to 28 February 2022 was classified into four cohorts by vaccination status. For every cohort, the hospital ward and ICU admission rates were calculated for each day between November 2021 and February 2022. Generalized linear models with a negative binomial distribution were used to estimate the age-adjusted hospitalization rate ratio of the cohort of individuals who had received a booster compared to the other cohorts. The age-adjusted rates of hospital ward and ICU admissions were 70.4 % and 72.0 % lower, respectively, in the fully vaccinated plus booster group compared to the fully vaccinated but no booster group. Analysing changes in the 14-day admission incidence rates showed that as the prevalence of the Omicron variant increased, the corresponding rate ratios decreased. The immunity acquired with the booster dose allowed the hospital network to meet all the demand for hospitalization during a period of high incidence of COVID-19, despite the fact that vaccine protection decreased as the prevalence of the Omicron variant increased.

Brief cognitive tests as a decision-making tool in primary care. A population and validation study

INTRODUCTION AND OBJECTIVES

Brief cognitive tests (BCT) are used in primary care (PC) for the detection of cognitive impairment (CI). Still, there are little data on their diagnostic utility (DU) in a community setting. This work evaluates the DU at the population level of Fototest, T@M, AD8 questionnaire and MMSE. It provides new cut-off points (CoP) validated in a CI early detection program.

MATERIAL AND METHODS

In the population and validation samples, the evaluation was carried out in two phases, a first of screening and administration of BCT and a second of clinical diagnosis, blinded to the results of the BCT, applying the current NIA-AA criteria. The DU of BCT in the population sample was evaluated with the area under the ROC curve (aROC). Youden index and the CoP with the best specificity that ensured a sensitivity of 80% were used to decide on the most appropriate CoP. The sensitivity, specificity, and predictive values for these CoP were calculated in the validation sample.

RESULTS

260 participants (23.1% with CI) from the population sample and 177 (42.4% with CI) from the validation sample were included. The Fototest has the best UD at the population level (aROC 0.851), which improves with the combination of Fototest and AD8 (aROC 0.875). The proposed CoP are AD8 ≥ 1, Fototest ≤ 35, T@M ≤ 40, and MMSE ≤ 26.

CONCLUSION

BCT are helpful in detecting CI in PC. This work supports the use of more demanding PoC.

Estimation of the epidemiology of dementia and associated neuropsychiatric symptoms by applying machine learning to real-world data

INTRODUCTION

Incidence rates of dementia-related neuropsychiatric symptoms (NPS) are not known and this hampers the assessment of their population burden. The objective of this study was to obtain an approximate estimate of the population incidence and prevalence of both dementia and NPS.

METHODS

Given the dynamic nature of the population with dementia, a retrospective study was conducted within the database of the Basque Health Service (real-world data) at the beginning and end of 2019. Validated random forest models were used to identify separately depressive and psychotic clusters according to their presence in the electronic health records of all patients diagnosed with dementia.

RESULTS

Among the 631,949 individuals over 60 years registered, 28,563 were diagnosed with dementia, of whom 15,828 (55.4%) showed psychotic symptoms and 19,461 (68.1%) depressive symptoms. The incidence of dementia in 2019 was 6.8/1000 person-years. Most incident cases of depressive (72.3%) and psychotic (51.9%) NPS occurred in cases of incident dementia. The risk of depressive-type NPS grows with years since dementia diagnosis, living in a nursing home, and female sex, but falls with older age. In the psychotic cluster model, the effects of male sex, and older age are inverted, both increasing the probability of this type of symptoms.

CONCLUSIONS

The stigmatization factor conditions the social and attitudinal environment, delaying the diagnosis of dementia, preventing patients from receiving adequate care and exacerbating families' suffering. This study evidences the synergy between big data and real-world data for psychiatric epidemiological research.

[Low transmission of SARS-CoV-2 at school settings: a population-based study in the Basque Country.]

OBJECTIVE

Studies about SARS-CoV-2 transmission at school settings have been outbreaks or schools clusters. There are scarce population-based studies has been studied. We aimed at describing SARS-CoV-2 school-related transmission and its relationship with baseline community cumulative incidence rate in the Basque Country after school reopening in order to inform Public Health decision-making.

METHODS

We conducted a scholar surveillance population-based study of SARS-CoV-2 transmission from 7 September to 31 October 2020. We calculated percentages of cases in school-age population, secondary attack rates by education level among close contacts and correlation between population´s and scholars´ incidence rates at municipal level.

RESULTS

There were 35,477 SARS-CoV-2 laboratory confirmed cases. Among them, 7.65% happened at school settings. Secondary attack rate at schools ranged from 2.9%, in preschools to 7.1% in high schools; Scholars caused a household and social secondary attack rate from 13% (high scholars) to 23.2% (elementary scholars). We found a low correlation between population´s and scholars´ incidence rates at municipal level (R2=0.047).

CONCLUSIONS

Secondary attack rate at school settings increased as educational level did; conversely, to social and family secondary attack rate, that decreased with higher educational level. School attendance, during a SARS-CoV-2 high transmission period showed feasible and did not rise transmission. These findings happened under strict non-pharmaceutical measures at school settings and proper epidemiological surveillance, including tracing of laboratory confirmed cases of SARS-CoV-2 looking for close contacts, isolation and testing of close contacts during isolation period. The different degree of transmission of the circulating variants in the different periods of the pandemic must also be taken into account.

Diagnostic accuracy of adenosine deaminase for pleural tuberculosis in a low prevalence setting: A machine learning approach within a 7-year prospective multi-center study

OBJECTIVE

To analyze the performance of adenosine deaminase in pleural fluid combined with other parameters routinely measured in clinical practice and assisted by machine learning algorithms for the diagnosis of pleural tuberculosis in a low prevalence setting, and secondly, to identify effusions that are non-tuberculous and most likely malignant.

PATIENTS AND METHODS

We prospectively analyzed 230 consecutive patients diagnosed with lymphocytic exudative pleural effusion from March 2013 to June 2020. Diagnosis according to the composite reference standard was achieved in all cases. Pre-test probability of pleural tuberculosis was 3.8% throughout the study period. Parameters included were: levels of adenosine deaminase, pH, glucose, proteins, and lactate dehydrogenase, red and white cell counts and lymphocyte percentage in pleural fluid, as well as age. We tested six different machine learning-based classifiers to categorize the patients. Two different classifications were performed: a) tuberculous/non-tuberculous and b) tuberculous/malignant/other.

RESULTS

Out of a total of 230 patients with pleural effusion included in the study, 124 were diagnosed with malignant effusion and 44 with pleural tuberculosis, while 62 were given other diagnoses. In the tuberculous/non-tuberculous classification, and taking into account the validation predictions, the support vector machine yielded the best result: an AUC of 0.98, accuracy of 97%, sensitivity of 91%, and specificity of 98%, whilst in the tuberculous/malignant/other classification, this type of classifier yielded an overall accuracy of 80%. With this three-class classifier, the same sensitivity and specificity was achieved in the tuberculous/other classification, but it also allowed the correct classification of 90% of malignant cases.

CONCLUSION

The level of adenosine deaminase in pleural fluid together with cell count, other routine biochemical parameters and age, combined with a machine-learning approach, is suitable for the diagnosis of pleural tuberculosis in a low prevalence scenario. Secondly, non-tuberculous effusions that are suspected to be malignant may also be identified with adequate accuracy.

Development and Validation of a Discrete Event Simulation Model to Evaluate the Cardiovascular Impact of Population Policies for Obesity

Introduction

Our aim was to describe the development and validation of an obesity model representing the cardiovascular risks associated with different body mass index (BMI) categories, through simulation, designed to evaluate the epidemiological and economic impact of population policies for obesity.

Methods

A discrete event simulation model was built in R considering the risk of cardiovascular events (heart failure, stroke, coronary heart disease, and diabetes) associated with BMI categories in the Spanish population. The main parameters included in the model were estimated from Spanish hospital discharge records and the Spanish Health Survey and allowed both first-order and second-order (probabilistic sensitivity analysis) uncertainty to be programmed into the model. The simulation yielded the incidence and prevalence of cardiovascular events as validation outputs. To illustrate the capacity of the model, we estimated the reduction in cardiovascular events and cost-utility (incremental cost/incremental quality-adjusted life-years [QALYs]) of a hypothetical intervention that fully eliminated the cardiovascular risks associated with obesity and overweight.

Results

The Validation Status of Health-Economic decision models (AdViSHE) tool was applied. Internal validation plots showed adequate goodness of fit for the Spanish population. External validation was achieved by comparing the simulated and real incidence by age group for stroke, acute myocardial infarction, and heart failure. The intervention reduced the population hazard ratios of stroke, acute myocardial infarction, and heart failure to 0.81, 0.74, and 0.78, respectively, and added 0.74 QALYs to the whole population.

Conclusions

This obesity simulation model evidenced good properties for estimating the long-term epidemiological and economic impact of policies to tackle obesity in Spain. The conceptual model could be implemented for other counties using country-specific input data.

Cerebrospinal Fluid 7-Ketocholesterol Level is Associated with Amyloid-β42 and White Matter Microstructure in Cognitively Healthy Adults

BACKGROUND

Abnormal cholesterol metabolism changes the neuronal membrane and may promote amyloidogenesis. Oxysterols in cerebrospinal fluid (CSF) are related to Alzheimer's disease (AD) biomarkers in mild cognitive impairment and dementia. Cholesterol turnover is important for axonal and white matter (WM) microstructure maintenance.

OBJECTIVE

We aim to demonstrate that the association of oxysterols, AD biomarkers, and WM microstructure occurs early in asymptomatic individuals.

METHODS

We studied the association of inter-individual variability of CSF 24-hydroxycholesterol (24-OHC), 27-hydroxycholesterol (27-OHC), 7-ketocholesterol (7-KC), 7β-hydroxycholesterol (7β-OHC), amyloid-β42 (Aβ42), total-tau (t-tau), phosphorylated-tau (p-tau), neurofilament (NfL), and WM microstructure using diffusion tensor imaging, generalized linear models and moderation/mediation analyses in 153 healthy adults.

RESULTS

Higher 7-KC levels were related to lower Aβ42, indicative of greater AD pathology (p = 0.041) .  Higher 7-KC levels were related to lower fractional anisotropy (FA) and higher mean (MD), axial (AxD), and radial (RD) diffusivity. 7-KC modulated the association between AxD and NfL in the corpus callosum splenium (B = 39.39, p = 0.017), genu (B = 68.64, p = 0.000), and fornix (B = 10.97, p = 0.000). Lower Aβ42 levels were associated to lower FA and higher MD, AxD, and RD in the fornix, corpus callosum, inferior longitudinal fasciculus, and hippocampus. The association between AxD and Aβ42 was moderated by 7K-C (p = 0.048).

CONCLUSION

This study adds clinical evidence to support the role of 7K-C on axonal integrity and the involvement of cholesterol metabolism in the Aβ42 generation process.

Plasma lipids are associated with white matter microstructural changes and axonal degeneration

Dislipidemia is a risk factor for cognitive impairment. We studied the association between interindividual variability of plasma lipids and white matter (WM) microstructure, using diffusion tensor imaging (DTI) in 273 healthy adults. Special focus was placed on 7 regions of interest (ROI) which are structural components of cognitive neurocircuitry. We also investigated the effect of plasma lipids on cerebrospinal fluid (CSF) neurofilament light chain (NfL), an axonal degeneration marker. Low density lipoprotein (LDL) and triglyceride (TG) levels showed a negative association with axial diffusivity (AxD) in multiple regions. High density lipoproteins (HDL) showed a positive correlation. The association was independent of Apolipoprotein E (APOE) genotype, blood pressure or use of statins. LDL moderated the relation between NfL and AxD in the body of the corpus callosum (p = 0.041), right cingulum gyrus (p = 0.041), right fornix/stria terminalis (p = 0.025) and right superior longitudinal fasciculus (p = 0.020) and TG in the right inferior longitudinal fasciculus (p = 0.004) and left fornix/stria terminalis (p = 0.001). We conclude that plasma lipids are associated to WM microstructural changes and axonal degeneration and might represent a risk factor in the transition from healthy aging to disease.

Estimation of the epidemiology of dementia and associated neuropsychiatric symptoms by applying machine learning to real-world data

INTRODUCTION

Incidence rates of dementia-related neuropsychiatric symptoms (NPS) are not known and this hampers the assessment of their population burden. The objective of this study was to obtain an approximate estimate of the population incidence and prevalence of both dementia and NPS.

METHODS

Given the dynamic nature of the population with dementia, a retrospective study was conducted within the database of the Basque Health Service (real-world data) at the beginning and end of 2019. Validated random forest models were used to identify separately depressive and psychotic clusters according to their presence in the electronic health records of all patients diagnosed with dementia.

RESULTS

Among the 631,949 individuals over 60 years registered, 28,563 were diagnosed with dementia, of whom 15,828 (55.4%) showed psychotic symptoms and 19,461 (68.1%) depressive symptoms. The incidence of dementia in 2019 was 6.8/1000 person-years. Most incident cases of depressive (72.3%) and psychotic (51.9%) NPS occurred in cases of incident dementia. The risk of depressive-type NPS grows with years since dementia diagnosis, living in a nursing home, and female sex, but falls with older age. In the psychotic cluster model, the effects of male sex, and older age are inverted, both increasing the probability of this type of symptoms.

CONCLUSIONS

The stigmatization factor conditions the social and attitudinal environment, delaying the diagnosis of dementia, preventing patients from receiving adequate care and exacerbating families' suffering. This study evidences the synergy between big data and real-world data for psychiatric epidemiological research.

Dynamic evaluation of the comparative effectiveness of an integrated program for heart failure care

RATIONALE, AIMS AND OBJECTIVES

An integrated care program for heart failure (HF) was developed in the Basque Country in 2013. The objective of this research was to evaluate its effectiveness through the number of hospital admissions in three integrated healthcare organizations (IHOs), taking into account the longitudinal nature of the disease and the intensity of the implementation.

METHODS

A retrospective observational study was carried out, based on data entered in administrative and clinical databases between 2014 and 2018 for a total population of 230 000. In addition to conventional statistical analyses, Andersen-Gill models for recurrent events were used, incorporating dynamic variables that allowed assessment of the intervention's intensity before each hospitalization.

RESULTS

A total of 6768 patients were analysed. Age (hazard ratio [HR] = 1.016; 95% confidence interval [CI] 1.011-1.022), the Charlson index (HR = 1.067, 95% CI 1.047-1.087), and the number of previous hospitalizations (HR = 1.632, 95% CI 1.557-1.712) were risk factors for readmission. Differences between IHOs were also statistically significant. Greater intervention intensity was associated with a lower hospitalization rate (HR = 0.995, 95% CI 0.990-1.000). As indicated by the interaction between intervention intensity and IHO, differences between IHOs disappeared when intensity rose. No inequities in hospitalization were found as a function of deprivation index or sex. Nonetheless, inequity in the implementation of the program by sex was clear, women with HF receiving less intense intervention than men with the same level of comorbidity and age.

CONCLUSIONS

The extent of program implementation measured by intervention intensity is a main driver of the effectiveness of an educational and monitoring program for HF. The evaluation of HF program effectiveness on readmissions must take into account the entire natural history of the disease. Implementation intensity explains differences between IHOs.

Economic evaluation of supplementing the diet with Souvenaid in patients with prodromal Alzheimer's disease

Background

The LipiDiDiet trial showed that Souvenaid, a medical food, might delay progression to dementia in prodromal Alzheimer’s disease (AD). The objective of this study was to assess the cost-utility of Souvenaid compared to placebo in patients with prodromal AD under the conditions applied in that trial.

Methods

A discrete event simulation model was developed based on the LipiDiDiet trial and a literature review to assess the cost-utility of Souvenaid from a societal perspective considering direct and indirect costs. For both intervention and control groups, patient trajectories in terms of functional decline on the Clinical Dementia Rating Sum of Boxes (CDR-SB) scale in LipiDiDiet were reproduced statistically with mixed models by assigning time until events to simulated patients. From the societal perspective, four scenarios were analysed by combining different options for treatment duration and diagnostic test cost. Univariate sensitivity analysis assessed parameter uncertainties.

Results

Validation results at year 2 of disease progression fit with CDR-SB progression in LipiDiDiet. The incremental cost-utility ratio (ICUR) in the baseline case was €22,743/quality-adjusted life year (QALY). All scenarios rendered an ICUR lower than €25,000/QALY (the societal threshold). Moreover, the treatment option was cost-saving and increased health benefits when diagnostic costs were not considered and treatment was only administered during the prodromal stage.

Conclusions

Treating prodromal AD with Souvenaid is a cost-effective intervention in all scenarios analysed. The LipiDiDiet trial showed a modest improvement in disease course but as the social costs of AD are very high, the intervention was efficient. Assessing small benefits at specific stages of AD is relevant because it is reasonable to expect that no effective, safe and affordable disease-modifying therapies will become available in the short to medium term.

Impact of an organised population screening programme for colorectal cancer: Measurement after first and second rounds

OBJECTIVE

The first and second rounds of the Basque programme for organised colorectal cancer screening were implemented between 2009 and 2014. Our objective was to measure the changes in incidence, tumour, node, metastasis staging distribution and tumour, node, metastasis-adjusted survival of patients with colorectal cancer from 2003 to 2014.

METHOD

Colorectal cancer cases with screening (patients <70 years old) and without screening (patients ≥70 years old) were compared during three four-year periods: 2003-2006, 2007-2010 and 2011-2014 (fully implemented phase). Cox regression, five-year relative survival and cancer probability of death were calculated for each four-year period, age group and tumour, node, metastasis stage. Adjusted incidence rates were analysed by joinpoint regression.

RESULTS

In an analysis of 23,301 cases of colorectal cancer, the incidence in patients younger than 70 years in 2013 showed a 17% annual decrease. The survival hazard ratios for stages I, II and III for 2003-2006 and 2007-2010 were compared to those for 2011-2014. From the first to the third period, diagnosis in the early stages (I and II) rose from 45.1% to 50.9% in the younger patient group and remained stable in the older group (49.6% and 49.4%). Additionally, the five-year relative survival rate increased significantly from 0.67 to 0.82 in those patients younger than 70 years, whereas in patients 70 years or older the rate did not change significantly (0.61 and 0.65).

CONCLUSION

The screening reduced incidence and improved survival by anticipating the diagnosis and by reducing mortality for each tumour, node, metastasis stage in the target population. The effect on survival could also be due to lead-time bias.

Validity of a computerised population registry of dementia based on clinical databases

INTRODUCTION

The handling of information through digital media allows innovative approaches for identifying cases of dementia through computerised searches within the clinical databases that include systems for coding diagnoses. The aim of this study was to analyse the validity of a dementia registry in Gipuzkoa based on the administrative and clinical databases existing in the Basque Health Service.

METHODS

This is a descriptive study based on the evaluation of available data sources. First, through review of medical records, the diagnostic validity was evaluated in two samples of cases identified and not identified as dementia. The sensitivity, specificity and positive and negative predictive value of the diagnosis of dementia were measured. Subsequently, the cases of living dementia in December 31, 2016 were searched in the entire Gipuzkoa population to collect sociodemographic and clinical variables.

RESULTS

The validation samples included 986 cases and 327 no cases. The calculated sensitivity was 80.2% and the specificity was 99.9%. The negative predictive value was 99.4% and positive value was 95.1%. The cases in Gipuzkoa were 10 551, representing 65% of the cases predicted according to the literature. Antipsychotic medication were taken by a 40% and a 25% of the cases were institutionalised.

CONCLUSIONS

A registry of dementias based on clinical and administrative databases is valid and feasible. Its main contribution is to show the dimension of dementia in the health system.

Changes in lung cancer survival by TNM stage in the Basque country from 2003 to 2014 according to period of diagnosis

INTRODUCTION

The objective of this study was to analyze the survival of patients with lung cancer by TNM stage in the 4-year periods 2003-2006, 2007-2010 and 2011-2014, treated in the Basque Health Service, and to compare this with survival in an equivalent sample of the general population.

METHODS

A retrospective observational design was applied to cases from the Hospital Cancer Registry of Euskadi. A cohort of 11,635 patients had complete data for the following variables: TNM stage, age, sex, histology, date of diagnosis, vital status and date of death. Relative survival and Cox and parametric regression models were used to assess changes in survival.

RESULTS

The lung cancer 5-year survival probability decreased with increasing stage, from 50-65% in patients with stage I disease to 2-3% in those with stage IV disease. Comparing patients diagnosed from 2011-2014 and 2003-2006, we found that survival improved: (a) the risk of death (hazard ratio) in 2003-2006 was 1.66 for stage I, 1.51 for stage II, 1.21 for stage III, and 1.10 for stage IV; (b) the 5-year relative survival increased from 11.0% to 17.8% in the period 2011-2014; and (c) the years of life lost decreased significantly from 2003-2006 to 2011-2014, varying between 6.16 (stage I) and 16.21 (stage IV).

CONCLUSIONS

Survival from lung cancer by stage in the Basque Country has lengthened significantly across all disease stages. Nonetheless, since we estimated that lung cancer patients still have significantly lower mean survival times than the general population, there is a need for more research to improve these outcomes.

Validation of Random Forest Machine Learning Models to Predict Dementia-Related Neuropsychiatric Symptoms in Real-World Data

BACKGROUND

Neuropsychiatric symptoms (NPS) are the leading cause of the social burden of dementia but their role is underestimated.

OBJECTIVE

The objective of the study was to validate predictive models to separately identify psychotic and depressive symptoms in patients diagnosed with dementia using clinical databases representing the whole population to inform decision-makers.

METHODS

First, we searched the electronic health records of 4,003 patients with dementia to identify NPS. Second, machine learning (random forest) algorithms were applied to build separate predictive models for psychotic and depressive symptom clusters in the training set (N = 3,003). Third, calibration and discrimination were assessed in the test set (N = 1,000) to assess the performance of the models.

RESULTS

Neuropsychiatric symptoms were noted in the electronic health record of 58% of patients. The area under the receiver operating curve reached 0.80 for the psychotic cluster model and 0.74 for the depressive cluster model. The Kappa index and accuracy also showed better discrimination in the psychotic model. Calibration plots indicated that both types of model had less predictive accuracy when the probability of neuropsychiatric symptoms was <25%. The most important variables in the psychotic cluster model were use of risperidone, level of sedation, use of quetiapine and haloperidol and the number of antipsychotics prescribed. In the depressive cluster model, the most important variables were number of antidepressants prescribed, escitalopram use, level of sedation, and age.

CONCLUSION

Given their relatively good performance, the predictive models can be used to estimate prevalence of NPS in population databases.

Economic evaluation of a population strategy for the treatment of chronic hepatitis C with direct-acting antivirals

The high initial cost of antivirals against hepatitis C prompted development of the "Strategic Plan for Tackling Chronic Hepatitis C in the Spanish National Health System". The objective of this study was the economic evaluation of the first two years of its application in Navarre, Spain. The change in the natural history of hepatitis C produced by the sustained virological response (SVR) was compared to an alternative without treatment and modeled with patient-level data. By means of a discrete events simulation model, the cost-effectiveness and the budget impact analysis of the treatment program were measured from the perspective of the Navarre Health Service. Of 656 patients treated, 98% had SVR. The average cost of the treatments was 18,743 euros per patient. The incremental cost-effectiveness ratio (ICER) with discount was 5,346 euros per quality-adjusted life years, which became more efficient as the stage of fibrosis increased until it reached levels of dominance in stage 4 fibrosis. The associated costs for chronic liver disease decreased as the benefit of the treatment was expressed. The implementation of the Strategic Plan is cost-effective, with an ICER well below the threshold, since the cost of treatment is largely compensated by savings in long-term health expenditure. The budgetary impact foresees a net saving from the third year on. The two key parameters were the decrease in the price of the treatment and the SVR in nearly 100% of the patients.

Dementia-related neuropsychiatric symptoms: inequalities in pharmacological treatment and institutionalization

BACKGROUND

Dementia-related neuropsychiatric symptoms (NPS) are the main determinant of family stress and institutionalization of patients. This study aimed to identify inequalities by gender and socioeconomic status in the management of NPS in patients diagnosed with dementia.

METHODS

An observational study was carried out to study all the cases of dementia in the corporate database of the Basque Health Service (29,864 patients). The prescription of antipsychotics and antidepressants and admission to a nursing home were used to establish the presence of NPS. The socioeconomic status of individuals was classified by a deprivation index. Logistic regressions were used to identify drivers for drug prescriptions and institutionalization.

RESULTS

NPS are poorly recorded in the clinical databases (12%). Neuropsychiatric symptoms were severe enough in two thirds of patients with dementia to be treated with psychoactive medication. Institutionalization showed an increase from those who did not receive medication to those who had been prescribed antidepressants (OR: 1.546), antipsychotics (OR: 2.075) or both (OR: 2.741). The resulting inequalities were the increased prescription of antidepressant drugs in women and more nursing-home admissions for women who were the least socioeconomically deprived and men who were the most deprived.

CONCLUSIONS

In large clinical databases, psychoactive drugs prescriptions can be useful to underscore the considerable burden of dementia-related NPS. Specific tools are needed to monitor social and health care programs targeted to dementia-related NPS from a population perspective. Programs aimed at reducing the family burden of care of dementia patients at home become the key elements in reducing inequalities in these patients' care. Socioeconomic status is the most important driver of inequality, and gender inequality may simply be hidden within the social environment. Integrated programs boosting the continuity of care are an objective for which compliance could be measured according to the NPS coding in the electronic health record.

Gender and socioeconomic inequalities in the implementation of the Basque programme for multimorbid patients

Background

The aim of our study was to increase awareness of the relevance of the implemented programmes to inequity of access and inequality of health by analyzing the impact of a patient-centred strategy for multimorbid patients.

Methods

This retrospective study compared the 2014 multimorbid patient group (intervention group) with its 2012 analogue (control group), before the Department of Health of the Basque Country launched the strategy for managing disease chronicity. Inequalities in healthcare access were represented by differences in the inclusion of patients in the programme and in contacts with primary care (PC) services by gender and socioeconomic status (measured by deprivation index by census track). Likewise, differences in hospital care represented inequalities in health outcomes. Generalized linear models were used to analyze relationships among variables. A propensity score by a genetic matching approach was used to minimize possible selection bias.

Results

At baseline, women had less probability of being eligible for the programme. No clear patterns were seen in resource consumption in PC. The probability of hospitalization was higher for men and increased according to socioeconomic status. The implementation of the programme yielded more contacts with PC services in all groups and a reduction in hospitalizations, especially among men and the most socioeconomically deprived patients.

Conclusion

The patient-centred, integrated-care intervention launched by the Department of Health of the Basque Country might have reduced some gender and socioeconomic inequalities in health outcomes, as it avoided more hospitalizations in subgroups that presented with more episodes of decompensation in the reference year.

Inequalities in health-related quality of life according to age, gender, educational level, social class, body mass index and chronic diseases using the Spanish value set for Euroquol 5D-5L questionnaire

BACKGROUND

Reducing health inequalities on the basis of social factors has been a key driver in the development of Public Health policies. Health-related quality of life is a global indicator useful to assess health inequalities within a society. The objective of this study was to identify inequalities on health by analysing the interactive effects of gender, age, educational level, social class, body mass index and chronic diseases on health-related quality of life in a Spanish population sample.

METHODS

We used data from the Spanish National Health Survey 2011-2012. Health-related quality of life was measured by the EQ-5D-5L instrument applying the Spanish value set. Probability of being in perfect health was ascertained by logistic regression models including gender, age, educational level, body mass index and social class and the corresponding terms of interaction. A two-part model combining logistic regression analysis and generalized linear models was applied to calculate the adjusted utility loss associated with chronic conditions (disutility values).

RESULTS

The sample used for analysis contained 18,450 individuals. The mean age was 50 years, 51.3% were women, 55% were overweight or obese and 46.7% had low social status. The mean utility was 0.94 in men and 0.89 in women. Elderly women, obese people, those of low social class and those with chronic conditions had significant lower utility values. Within the regression analysis, interaction assessment revealed that the detrimental effect of obesity disappeared in higher social classes. Utility values for all chronic conditions considered were lower in women than in men and were on a gradient within social class, the lowest for individuals declaring stroke. The greatest decrease on health-related quality of life was determined by declaration of stroke (17.6%) or mental diseases (18.6%).

CONCLUSIONS

The interactive effects of gender, age, educational level, social class, body mass index and chronic diseases on health-related quality of life in the Spanish population revealed important inequalities in health. Social class acted as a modulator of the stigma associated with obesity. Chronic conditions producing loss of autonomy had the greatest impact on reduction of health-related quality of life. This is the first study using the Spanish EQ-5D-5L value set to estimate utilities.

[Factors associated with the prevalence of hypovitaminosis D in pregnant women and their newborns]

BACKGROUND

The finding of hypovitaminosis in pregnancy D has prompted the debate about its supplementation. The objective of the study was to measure the prevalence of hypovitaminosis D in mothers and newborns.

METHODS

A one-year observational study was conducted including the measuring of vitamin D levels in mothers and in the umbilical cord blood of newborns. An analysis was made of the variables as regards maternal characteristics, delivery and sun exposure.

RESULTS

Values lower than 20 ng/ml were found in 64.4% of 745 mothers and 41.3% of 560 newborns, and less than 30 ng/ml in 88.7% and 67.1%, respectively. Mean levels were higher in summer-autumn than in winter-spring (21.73 and 13.70 ng / ml in mothers and 29.04 and 20.49 ng/ml in cord), and higher in the umbilical cord than in the maternal plasma. Multiple pregnancies (OR: 6.29) and non-European origin (OR: 13.09) were risk factors for maternal hypovitaminosis, while maternal supplementation (OR: 0.19), physical activity (OR: 0.57), and sun exposure (OR: 0.46) had a preventive effect.

CONCLUSIONS

The high rates of hypovitaminosis support the policy of giving dietary supplements to newborns. The high level of hypovitaminosis found supports the extension of screening and supplementation to all pregnant women, and not only to those with risk factors. The greater difference between mothers and newborns in seasons of low sun exposure can be interpreted as a protective effect.

Impact of stratification on the effectiveness of a comprehensive patient-centered strategy for multimorbid patients

OBJECTIVE

The objective of this work was to assess the effectiveness of a population-level patient-centered intervention for multimorbid patients based on risk stratification for case finding in 2014 compared with the baseline scenario in 2012.

DATA SOURCE

Clinical and administrative databases.

STUDY DESIGN

This was an observational cohort study with an intervention group and a historical control group. A propensity score by a genetic matching approach was used to minimize bias. Generalized linear models were used to analyze relationships among variables.

DATA COLLECTION

We included all eligible patients at the beginning of the year and followed them until death or until the follow-up period concluded (end of the year). The control group (2012) totaled 3558 patients, and 4225 patients were in the intervention group (2014).

PRINCIPAL FINDING

A patient-centered strategy based on risk stratification for case finding and the implementation of an integrated program based on new professional roles and an extensive infrastructure of information and communication technologies avoided 9 percent (OR: 0.91, CI: 0.86-0.96) of hospitalizations. However, this effect was not found in nonprioritized groups whose probability of hospitalization increased (OR: 1.19, CI = 1.09-1.30).

CONCLUSIONS

In a before-and-after analysis using propensity score matching, a comprehensive, patient-centered, integrated care intervention was associated with a lower risk of hospital admission among prioritized patients, but not among patients who were not prioritized to receive the intervention.

Increased CAIDE dementia risk, cognition, CSF biomarkers, and vascular burden in healthy adults

OBJECTIVE

To investigate the cognitive profile of healthy individuals with increased Cardiovascular Risk Factors, Aging and Dementia (CAIDE) dementia risk score and to explore whether this association is related to vascular burden and CSF biomarkers of amyloidosis and neurodegeneration.

METHOD

Cognitively normal participants (mean age 57.6 years) from the Gipuzkoa Alzheimer Project study were classified as having high risk (HR; n = 82) or low risk (LR; n = 293) for dementia according to a CAIDE score cutoff of 9. Cognitive composites were compared between groups. We explored using generalized linear models the role of APOE genotype, MRI white matter hyperintensities (WMH), and CSF (n = 218) levels of β-amyloid_1-42 (Aβ_1-42), total tau (t-tau), and phosphorylated tau (p-tau) in the association between CAIDE score and cognition.

RESULTS

HR participants obtained lower scores on executive function (EF) (p = 0.001) and visual perception and construction (VPC) (p < 0.001) composites. EF composite was associated with CAIDE score × p-tau (p = 0.001), CAIDE score × t-tau (p = 0.001), and WMH (p = 0.003). VPC composite was associated with APOE (p = 0.001), Aβ_1-42 (p = 0.004), the interaction APOE × Aβ_1-42 (p = 0.003), and WMH (p = 0.004). Performance on global memory was associated with Aβ_1-42 (p = 0.006), APOE (p = 0.008), and their interaction (p = 0.006). Analyses were adjusted for age, education, sex, premorbid intelligence, and stress.

CONCLUSION

Healthy participants at increased dementia risk based on CAIDE scores show lower performance in EF and VPC. This difference is related to APOE, WMH, and Alzheimer biomarkers.

Cost-effectiveness analysis of laparoscopic versus open surgery in colon cancer

BACKGROUND

Few economic evaluations have assessed laparoscopy for colon cancer. This study aimed to compare the cost-effectiveness of laparoscopic and open surgery for the treatment of colon cancer.

METHOD

A cost-effectiveness analysis was performed comparing two groups of patients treated according to standard clinical practice (REDISSEC-CARESS/CCR cohort) by laparoscopic or open surgery. Data were collected from health records on clinical characteristics and resource use over 2 years after surgery. To calculate the incremental cost-effectiveness ratio, costs and quality-adjusted life years (QALYs) were obtained for each patient. Clinical heterogeneity was addressed using propensity score and joint multivariable analysis (seemingly unrelated regression) that included interactions between TNM stage, age, and surgical procedure to perform subgroup analysis.

RESULTS

The sample was composed of 1591 patients, 963 who underwent laparoscopy and 628 open surgery. Using propensity score and regression analysis, we found that laparoscopy was associated with more QALYs and less resource use than open surgery (0.0163 QALYs, 95% CI 0.0114-0.0212; and - €3461, 95% CI - 3337 to - 3586). Costs were lower for laparoscopy in all subgroups. In the subgroups younger than 80 years old, utility was higher in patients who underwent laparoscopy. Nevertheless, open surgery had better outcomes in older patients in stages I-II (0.0618 QALYs) and IV (0.5090 QALYs).

CONCLUSION

Overall, laparoscopy appears to be dominant, resulting in more QALYs and lower costs. Nevertheless, while laparoscopy required fewer resources in all subgroups, outcomes may be negatively affected in elderly patients, representing an opportunity for shared decision making between surgeons and patients. ClinicalTrials.gov Identifier: NCT02488161.

Validity of a computerized population registry of dementia based on clinical databases

INTRODUCTION

The handling of information through digital media allows innovative approaches for identifying cases of dementia through computerized searches within the clinical databases that include systems for coding diagnoses. The aim of this study was to analyze the validity of a dementia registry in Gipuzkoa based on the administrative and clinical databases existing in the Basque Health Service.

METHODS

This is a descriptive study based on the evaluation of available data sources. First, through review of medical records, the diagnostic validity was evaluated in 2 samples of cases identified and not identified as dementia. The sensitivity, specificity and positive and negative predictive value of the diagnosis of dementia were measured. Subsequently, the cases of living dementia in December 31, 2016 were searched in the entire Gipuzkoa population to collect sociodemographic and clinical variables.

RESULTS

The validation samples included 986 cases and 327 no cases. The calculated sensitivity was 80.2% and the specificity was 99.9%. The negative predictive value was 99.4% and positive value was 95.1%. The cases in Gipuzkoa were 10,551, representing 65% of the cases predicted according to the literature. Antipsychotic medication were taken by a 40% and a 25% of the cases were institutionalized.

CONCLUSIONS

A registry of dementias based on clinical and administrative databases is valid and feasible. Its main contribution is to show the dimension of dementia in the health system.

Cost-effectiveness and budget impact analyses of a colorectal cancer screening programme in a high adenoma prevalence scenario using MISCAN-Colon microsimulation model

Background

The Basque Colorectal Cancer Screening Programme began in 2009 and the implementation has been complete since 2013. Faecal immunological testing was used for screening in individuals between 50 and 69 years old. Colorectal Cancer in Basque country is characterized by unusual epidemiological features given that Colorectal Cancer incidence is similar to other European countries while adenoma prevalence is higher. The object of our study was to economically evaluate the programme via cost-effectiveness and budget impact analyses with microsimulation models.

Methods

We applied the Microsimulation Screening Analysis (MISCAN)-Colon model to predict trends in Colorectal Cancer incidence and mortality and to quantify the short- and long-term effects and costs of the Basque Colorectal Cancer Screening Programme. The model was calibrated to the Basque demographics in 2008 and age-specific Colorectal Cancer incidence data in the Basque Cancer Registry from 2005 to 2008 before the screening begun. The model was also calibrated to the high adenoma prevalence observed for the Basque population in a previously published study. The multi-cohort approach used in the model included all the cohorts in the programme during 30 years of implementation, with lifetime follow-up. Unit costs were obtained from the Basque Health Service and both cost-effectiveness analysis and budget impact analysis were carried out.

Results

The goodness-of-fit of the model adaptation to observed programme data was evidence of validation. In the cost-effectiveness analysis, the savings from treatment were larger than the added costs due to screening. Thus, the Basque programme was dominant compared to no screening, as life expectancy increased by 29.3 days per person. The savings in the budget analysis appeared 10 years after the complete implementation of the programme. The average annual budget was €73.4 million from year 2023 onwards.

Conclusions

This economic evaluation showed a screening intervention with a major health gain that also produced net savings when a long follow-up was used to capture the late economic benefit. The number of colonoscopies required was high but remain within the capacity of the Basque Health Service. So far in Europe, no other population Colorectal Cancer screening programme has been evaluated by budget impact analysis.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4362-1) contains supplementary material, which is available to authorized users.

[The impact of patient identification on an integrated program of palliative care in Basque Country]

Objetivo

Evaluar el proceso y el impacto económico de un programa integrado de cuidados paliativos.

Diseño

Estudio transversal comparativo.

Emplazamiento

Organizaciones Sanitarias Integradas Alto Deba y Goierri Alto-Urola, País Vasco.

Participantes

Pacientes fallecidos (oncológicos y no oncológicos) en 2012 (grupo control) y 2015 (grupo intervención) susceptibles de necesitar cuidados paliativos según la estimación mínima de McNamara.

Intervenciones

Identificación de pacientes con el código de cuidados paliativos en atención primaria, uso de rutas asistenciales conjuntas en atención primaria y hospitalaria e impartición de cursos formativos.

Mediciones principales

Cambio en el perfil de uso de recursos del paciente durante sus últimos 3 meses de vida. Se utilizó el genetic matching para evitar sesgos. Mediante análisis univariante se compararon los grupos y mediante regresiones logísticas y modelos lineales generalizados se analizaron las relaciones entre variables.

Resultados

Se identificaron 1.023 pacientes en 2012 y 1.142 en 2015. En 2015 aumentó al doble la probabilidad de ser identificado como paliativo en pacientes oncológicos (19-33%) y no oncológicos (7-16%). La prescripción de opiáceos subió (25-68%) y el fallecimiento en hospital se mantuvo estable. Los contactos por paciente con atención primaria y hospitalización a domicilio aumentaron, mientras que las hospitalizaciones tradicionales disminuyeron. El coste por paciente aumentó un 26%.

Conclusiones

El modelo integrado incrementó la identificación de la población diana. La relación entre variables mostró que la identificación repercutió positivamente en la prescripción de opiáceos, fallecimiento fuera del hospital y extensión a enfermedades no oncológicas. Aunque también disminuyeron los ingresos, el coste aumentó debido al uso de hospitalización a domicilio.

Evaluation of the colorectal cancer screening Programme in the Basque Country (Spain) and its effectiveness based on the Miscan-colon model

Abstract

The population-based Basque Colorectal Cancer (CRC) Screening Programme started in 2009 with a biennial immunochemical quantitative test (FIT) biennial and colonoscopy under sedation in positive cases. The population target of 586,700 residents was from 50 to 69 years old and the total coverage was reached at the beginning of 2014. The aim of our study was to determine possible scenarios in terms of incidence, mortality and reduction of Life-years-Lost (L-y-L) in the medium and long term of CRC.

Methods

Invitations were sent out by the Programme from 2009 to 2014, with combined organizational strategies. Simulation was done by MISCAN-colon (Microsimulation Screening Analysis) over 30 years comparing the results of screening vs no-screening, taking the population-based Cancer Registry into account. Lifetime population and real data from the Programme were used from 2008 to 2012. The model was run differentially for men and women.

Results

924,416 invitations were sent out from 2009 to 2014. The average participation rate was 68.4%, CRC detection rate was 3.4% and the Advanced Adenoma detection rate was 24.0‰, with differences observed in sex and age. Future scenarios showed a higher decrease of incidence (17.2% vs 14.7%), mortality (28.1% vs 22.4%) and L-y-L (22.6% vs 18.4%) in men than women in 2030.

Conclusions

The Basque Country CRC Programme results are aligned to its strategy and comparable to other programmes. MISCAN model was found to be a useful tool to predict the benefits of the programme in the future. The effectiveness of the Programme has not been formally established as case control studies are required to determine long term benefits from the screening strategy.

The cost of colorectal cancer according to the TNM stage

INTRODUCTION

The aim of this study was to measure the cost of treatment of colorectal cancer in the Basque public health system according to the clinical stage.

METHODS

We retrospectively collected demographic data, clinical data and resource use of a sample of 529 patients. For stagesi toiii the initial and follow-up costs were measured. The calculation of cost for stageiv combined generalized linear models to relate the cost to the duration of follow-up based on parametric survival analysis. Unit costs were obtained from the analytical accounting system of the Basque Health Service.

RESULTS

The sample included 110 patients with stagei, 171 with stageii, 158 with stageiii and 90 with stageiv colorectal cancer. The initial total cost per patient was 8,644€ for stagei, 12,675€ for stageii and 13,034€ for stageiii. The main component was hospitalization cost. Calculated by extrapolation for stageiv mean survival was 1.27years. Its average annual cost was 22,403€, and 24,509€ to death. The total annual cost for colorectal cancer extrapolated to the whole Spanish health system was 623.9million€.

CONCLUSIONS

The economic burden of colorectal cancer is important and should be taken into account in decision-making. The combination of generalized linear models and survival analysis allows estimation of the cost of metastatic stage.

Incorporating Budget Impact Analysis in the Implementation of Complex Interventions: A Case of an Integrated Intervention for Multimorbid Patients within the CareWell Study

OBJECTIVES

To develop a framework for the management of complex health care interventions within the Deming continuous improvement cycle and to test the framework in the case of an integrated intervention for multimorbid patients in the Basque Country within the CareWell project.

METHODS

Statistical analysis alone, although necessary, may not always represent the practical significance of the intervention. Thus, to ascertain the true economic impact of the intervention, the statistical results can be integrated into the budget impact analysis. The intervention of the case study consisted of a comprehensive approach that integrated new provider roles and new technological infrastructure for multimorbid patients, with the aim of reducing patient decompensations by 10% over 5 years. The study period was 2012 to 2020.

RESULTS

Given the aging of the general population, the conventional scenario predicts an increase of 21% in the health care budget for care of multimorbid patients during the study period. With a successful intervention, this figure should drop to 18%. The statistical analysis, however, showed no significant differences in costs either in primary care or in hospital care between 2012 and 2014. The real costs in 2014 were by far closer to those in the conventional scenario than to the reductions expected in the objective scenario. The present implementation should be reappraised, because the present expenditure did not move closer to the objective budget.

CONCLUSIONS

This work demonstrates the capacity of budget impact analysis to enhance the implementation of complex interventions. Its integration in the context of the continuous improvement cycle is transferable to other contexts in which implementation depth and time are important.

Projecting Burden of Dementia in Spain, 2010-2050: Impact of Modifying Risk Factors

Risk and protective factors such as obesity, hypercholesterolemia, physical activity, and hypertension can play a role in the development of dementia. Our objective was to measure the effect of modification of risk and protective factors on the prevalence and economic burden of dementia in the aging Spanish population during 2010-2050. A discrete event simulation model including risk and protective factors according to CAIDE (Cardiovascular Risk Factors, Aging and Incidence of Dementia) Risk Score was built to represent the natural history of dementia. Prevalence of dementia was calculated from 2010 to 2050 according to different scenarios of risk factor prevalence to assess the annual social and health care costs of dementia. The model also supplied hazard ratios for dementia. Aging will increase between 49% and 16% each decade in the number of subjects with dementia. The number of working-age individuals per person with dementia will decrease to a quarter by 2050. An intervention leading to a 20% change in risk and protective factors would reduce dementia by 9% , prevent over 100,000 cases, and save nearly 4,900 million euros in 2050. Switching individuals from a group with a specific risk factor to one without it nearly halved the risk of the development of dementia. Dementia prevalence will grow unmanageable if effective prevention strategies are not developed. Interventions aiming to reduce modifiable risk factor prevalence represent valid and effective alternatives to reduce dementia burden. However, further research is needed to identify causal relationships between dementia and risk factors.

Economic evaluation of the breast cancer screening programme in the Basque Country: retrospective cost-effectiveness and budget impact analysis

Background

Breast cancer screening in the Basque Country has shown 20 % reduction of the number of BC deaths and an acceptable overdiagnosis level (4 % of screen detected BC). The aim of this study was to evaluate the breast cancer early detection programme in the Basque Country in terms of retrospective cost-effectiveness and budget impact from 1996 to 2011.

Methods

A discrete event simulation model was built to reproduce the natural history of breast cancer (BC). We estimated for lifetime follow-up the total cost of BC (screening, diagnosis and treatment), as well as quality-adjusted life years (QALY), for women invited to participate in the evaluated programme during the 15-year period in the actual screening scenario and in a hypothetical unscreened scenario. An incremental cost-effectiveness ratio was calculated with the use of aggregated costs. Besides, annual costs were considered for budget impact analysis. Both population level and single-cohort analysis were performed. A probabilistic sensitivity analysis was applied to assess the impact of parameters uncertainty.

Results

The actual screening programme involved a cost of 1,127 million euros and provided 6.7 million QALYs over the lifetime of the target population, resulting in a gain of 8,666 QALYs for an additional cost of 36.4 million euros, compared with the unscreened scenario. Thus, the incremental cost-effectiveness ratio was 4,214€/QALY. All the model runs in the probabilistic sensitivity analysis resulted in an incremental cost-effectiveness ratio lower than 10,000€/QALY. The screening programme involved an increase of the annual budget of the Basque Health Service by 5.2 million euros from year 2000 onwards.

Conclusions

The BC screening programme in the Basque Country proved to be cost-effective during the evaluated period and determined an affordable budget impact. These results confirm the epidemiological benefits related to the centralised screening system and support the continuation of the programme.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2386-y) contains supplementary material, which is available to authorized users.

[Prevalence of altered mismatch repair protein nuclear expression detected by immunohistochemistry on adenomas with high-grade dysplasia and features associated with this risk in a population-based study]

INTRODUCTION

Alteration of mismatch repair system protein expression detected by immunohistochemistry (IHQ) in tumoural tissue is a useful technique for Lynch Syndrome (LS) screening. A recent review proposes LS screening through immunohistochemical study not only in all diagnosed cases of colorectal cancer (CRC) but also in advanced adenomas, especially in young patients.

OBJECTIVE

To assess the prevalence of altered IHQ carried out in all adenomas with high-grade dysplasia (HGD) diagnosed in our community in 2011, as well as the variables associated with this alteration.

METHODS

We included all the cases of adenomatous polyps with HGD diagnosed in the three public pathology laboratories of Navarre during 2011 and performed a statistical study to assess the association between different patient and lesion characteristics and altered IHQ results.

RESULTS

A total of 213 colonic adenomas with HGD were diagnosed, and 26 (12.2%) cases were excluded from the final analysis (2 known LS, 22 without IHQ study and 2 with inconclusive IHQ studies). The final number of adenomas included was 187. Pathologic results were found in 10 cases (5.35%)-6 cases in MLH1 and PMS2, 2 cases in PMS2, 1 case in MSH6 and 1 case in MSH2 and MSH6. The factors showing a statistically significant association with the presence of abnormal proteins were the synchronous presence of CRC, the presence of only one advanced adenoma, proximal location of HGD and age <50 years.

CONCLUSIONS

The percentage of pathologic nuclear expression found in IHQ is high. Consequently, screening of all diagnosed HGD could be indicated, especially in young patients, with a single AA and proximal HGD.

[Cost of breast cancer treatment by clinical stage in the Basque Country, Spain]

BACKGROUND

The burden of breast cancer is important for the healthcare system. In the context of the evaluation of the breast cancer screening program in the Basque Country it is important to determine the unitary costs related to diagnosis as well as the treatment costs depending on the clinical stage at detection. The main objective was to calculate the total cost and the components of breast cancer (BC) treatment depending on the clinical stage by 2011.

METHODS

The estimated costs include BC diagnosis as so as to initial treatment and follow-up, based on resource consumption and unitary costs of the Basque Health Services. Micro-costing technique was applied based on the clinical guidelines.

RESULTS

Our model showed the estimated loss of productivity due to premature The initial cost was 9.838€ for the stage 0, 17.273€ for stage I, 22.145€ for stage II and 28.776€ for stage III. The follow up annual cost was 172€ for the stage 0, 908€ for stage I, 994€ for stage II and 1.166€ for stage III. The annual cost for stage IV was 17879€.

CONCLUSIONS

Chemotherapy determines the greatest percentage of BC costs. The two main drivers of the total cost of breast cancer are the initial treatment of stages I to III and the cost of stage IV, the latter reaching € 50,061 per patient.

Evaluation of health benefits and harms of the breast cancer screening programme in the Basque Country using discrete event simulation

BACKGROUND

Since the breast cancer screening programme in the Basque Country (BCSPBC) was started in 1996, more than 400,000 women aged 50 to 69 years have been invited to participate. Based on epidemiological observations and simulation techniques it is possible to extend observed short term data into anticipated long term results. The aim of this study was to assess the effectiveness of the programme through 2011 by quantifying the outcomes in breast cancer mortality, life-years gained, false positive results, and overdiagnosis.

METHODS

A discrete event simulation model was constructed to reproduce the natural history of breast cancer (disease-free, pre-clinical, symptomatic, and disease-specific death) and the actual observed characteristics of the screening programme during the evaluated period in the Basque women population. Goodness-of-fit statistics were applied for model validation. The screening effects were measured as differences in benefits and harms between the screened and unscreened populations. Breast cancer mortality reduction and life-years gained were considered as screening benefits, whereas, overdiagnosis and false positive results were assessed as harms. Results for a single cohort were also obtained.

RESULTS

The screening programme yielded a 16 % reduction in breast cancer mortality and a 10 % increase in the incidence of breast cancer through 2011. Almost 2 % of all the women in the programme had a false positive result during the evaluation period. When a single cohort was analysed, the number of deaths decreased by 13 %, and 4 % of screen-detected cancers were overdiagnosed. Each woman with BC detected by the screening programme gained 2.5 life years due to early detection corrected by lead time.

CONCLUSIONS

Fifteen years after the screening programme started, this study supports an important decrease in breast cancer mortality due to the screening programme, with reasonable risk of overdiagnosis and false positive results, and sustains the continuation of the breast cancer screening programme in the Basque population.

Cost-Effectiveness Analysis of a National Newborn Screening Program for Biotinidase Deficiency

BACKGROUND AND OBJECTIVES

There are conflicting views as to whether testing for biotinidase deficiency (BD) ought to be incorporated into universal newborn screening (NBS) programs. The aim of this study was to evaluate the cost-effectiveness of adding BD to the panel of conditions currently screened under the national NBS program in Spain.

METHODS

We used information from the regional NBS program for BD that has been in place in the Spanish region of Galicia since 1987. These data, along with other sources, were used to develop a cost-effectiveness decision model that compared lifetime costs and health outcomes of a national birth cohort of newborns with and without an early detection program. The analysis took the perspective of the Spanish National Health Service. Effectiveness was measured in terms of quality-adjusted life years (QALYs). We undertook extensive sensitivity analyses around the main model assumptions, including a probabilistic sensitivity analysis.

RESULTS

In the base case analysis, NBS for BD led to higher QALYs and higher health care costs, with an estimated incremental cost per QALY gained of $24,677. Lower costs per QALY gained were found when conservative assumptions were relaxed, yielding cost savings in some scenarios. The probability that BD screening was cost-effective was estimated to be >70% in the base case at a standard threshold value.

CONCLUSIONS

This study indicates that NBS for BD is likely to be a cost-effective use of resources.

Regional variability in changes in the incidence of hip fracture in the Spanish population (2000-2012)

The objective is to analyse the evolution of the incidence of hip fracture in the female population of Spain from 2000 to 2012 and to establish the possible changes which may have been seen over this period of time, including the trends in the different regions of the country.

INTRODUCTION

Fragility-related hip fractures are considered to be the fractures of greatest significance to public health due to their high degree of morbidity and mortality. The change in their incidence, both in absolute values and when adjusted for age, is the subject of debate. The objective of this article is to describe the changes in the rates of hip fracture in Spain by autonomous community between the years 2000 and 2012.

METHODS

Using the data from the Spanish Minimum Basic Data Set, in which are all the recorded cases of women with a principal diagnosis of hip fracture, the incidence rates by age group and by autonomous community were obtained. Poisson distribution or negative binomial regressions were carried out to estimate the average annual change over the time period analysed.

RESULTS

There have been statistically significant changes in the trends of rates of incidence for all age groups of women over 65 years of age. The annual reduction was 2.2% for women of 65-74 years of age and less for those between 75 and 84. The rates of incidence for those over 85 increased annually by 0.58%.

CONCLUSIONS

Hip fractures continue to increase in absolute numbers, although if the rates are adjusted for age, a downward trend is seen in certain age groups. These findings have various origins, although in the absence of great changes in population structure, we believe that drug treatments for osteoporosis may play a role. There is variability in the change in incidence of hip fractures in different parts of the country. Further studies are required to be able to identify the causes.

Fitting the epidemiology and neuropathology of the early stages of Alzheimer's disease to prevent dementia

Introduction

Recent research on biomarkers has made possible the diagnosis of pre-dementia and even preclinical Alzheimer’s disease (AD), thus providing the ideal context for prevention. The aim of this study was to investigate the epidemiology of the early stages of AD by fitting neuropathologic and epidemiological data to assess the feasibility of prevention programs.

Methods

The study addressed primarily the construction of a discrete event simulation model of the stages of dementia. Age was included in the mathematical functions to combine the two competitive risks that determine the epidemiology of AD, that is, time to onset of dementia and time until death by other causes. Subsequently, this model was calibrated to reproduce the prevalence of pathological findings associated with AD. The beginning of the preclinical stage was taken to coincide with Thal phase 1 deposition of amyloid-beta. The duration of the prodromal stage, marked by mild cognitive impairment, was based on a 10% annual conversion rate from this level of impairment to dementia. The validation of prevalence figures also permitted estimation of the incidence and duration of preclinical and prodromal stages.

Results

In Spain, half of the nearly 10 million people aged more than 60 years are in the early stages of AD; 35.9% are in a preclinical stage, and up to 14.2% are in a prodromal stage. However, dementia will develop in only 38% of this population. The weighted mean time to dementia was 22.0 years from the start of Thal phase 1 and 9.0 years from the start of phase 2. Results of simulation models showed a lack of correlation between clinical and pathological classifications.

Conclusions

These findings raise questions about the feasibility of drug-based prevention strategies. Currently, screening programs with biomarkers in the early stages of AD cannot be applied to the half of the general population older than 60 years. Hence, intensive research is needed regarding risk factors, so that more affordable strategies may be planned. More efficient criteria are also needed to select those subjects with mild cognitive impairment who have an increased probability of positive screening for biomarkers (prodromal stage).

Electronic supplementary material

The online version of this article (doi:10.1186/s13195-014-0079-9) contains supplementary material, which is available to authorized users.

Budget impact analysis of switching to digital mammography in a population-based breast cancer screening program: a discrete event simulation model

Objective

To assess the budgetary impact of switching from screen-film mammography to full-field digital mammography in a population-based breast cancer screening program.

Methods

A discrete-event simulation model was built to reproduce the breast cancer screening process (biennial mammographic screening of women aged 50 to 69 years) combined with the natural history of breast cancer. The simulation started with 100,000 women and, during a 20-year simulation horizon, new women were dynamically entered according to the aging of the Spanish population. Data on screening were obtained from Spanish breast cancer screening programs. Data on the natural history of breast cancer were based on US data adapted to our population. A budget impact analysis comparing digital with screen-film screening mammography was performed in a sample of 2,000 simulation runs. A sensitivity analysis was performed for crucial screening-related parameters. Distinct scenarios for recall and detection rates were compared.

Results

Statistically significant savings were found for overall costs, treatment costs and the costs of additional tests in the long term. The overall cost saving was 1,115,857€ (95%CI from 932,147 to 1,299,567) in the 10^th year and 2,866,124€ (95%CI from 2,492,610 to 3,239,638) in the 20^th year, representing 4.5% and 8.1% of the overall cost associated with screen-film mammography. The sensitivity analysis showed net savings in the long term.

Conclusions

Switching to digital mammography in a population-based breast cancer screening program saves long-term budget expense, in addition to providing technical advantages. Our results were consistent across distinct scenarios representing the different results obtained in European breast cancer screening programs.

[Cost and mortality associated to the surgical delay of patients with a hip fracture. Spain]

BACKGROUND

Hip fractures surgery is often delayed for several days. The present work has two objectives. The first one is to determine the preoperative hospital length of stay of patients with a hip fracture in our region and its possible correlation with an increase in mortality rate. Secondly we assessed the healthcare expenditure associated to this preoperative period.

METHODS

We carried out an observational, retrospective study in which all hip fractures attended in the Basque Country throughout 2010 were assessed by the Minimun Basic Data Set (MSBD): hospital, age, sex, preoperative hospital length, status at hospital discharge, comorbidities and surgical procedure. Furthermore we studied the Charlson Index and the total cost associated stratified by pre and post-operative period using a multiple model regression.

RESULTS

A total of 1856 surgical procedures were analyzed. Average pre and post-operative length of stay was 2.7 and 9.7 days respectively. The mean total cost per hospital admission was 12,552 € with 1,295.5 € € corresponding to the preoperative period. The duration of preoperative stay is not associated with a significant reduction in mortality, although it did with an increase in the total cost.

CONCLUSIONS

Preoperative hospital stay in patients with hip fracture is still challenging. We could not find an association between the delays in surgical procedures and hospital mortality, although it seems to be associated with an increased the total procedure cost. These results can serve as a foundation for setting up strategies to decrease the length of hospital stay, not only for cost-saving purposes.