Einsatz entscheidungsanalytischer Modelle für die ökonomische Evaluation medizinischer Verfahren am Beispiel chronisch obstruktiver Lungenerkrankungen

Die chronisch obstruktive Lungenerkrankung (COPD), derzeit weltweit die vierthäufigste Todesursache, hat schwerwiegende Auswirkungen auf die betroffenen Patienten und verursacht jedes Jahr hohe Kosten für die Gesellschaft. Ziel dieser Arbeit war es, ein entscheidungsanalytisches Modell zu COPD mit aktuellen Parametern für Deutschland zu erstellen, das zur gesundheitsökonomischen Evaluation von Interventionen eingesetzt werden kann. Dazu wurde ein Markov-Modell mit sieben Zuständen entwickelt, mit dem eine Kosten-Nutzwert-Analyse aus gesellschaftlicher Perspektive mit einer Laufzeit von 60 Jahren durchgeführt wurde. Die Patienten starteten im Alter von 45 und mit leichter COPD in das Modell. Neben Wahrscheinlichkeiten für die Übergänge zwischen den Zuständen wurden auch stadienspezifische Nutzwerte und Kosten bestimmt und jeweils mit 3% diskontiert. Die Schätzung der Übergangswahrscheinlichkeiten basiert auf umfangreichen Literaturrecherchen, um für jeden Bereich die beste derzeit verfügbare Evidenz zu identifizieren. Da kaum deutsche Studien zum Krankheitsverlauf von COPD existieren, mussten größtenteils die Ergebnisse internationaler Studien verwendet werden. Im Bereich von Nutzwerten bei akuten Exazerbationen lagen dagegen auch international kaum Informationen vor. Daher wurde eine eigene Studie zur Gewinnung solcher Nutzwerte geplant und in Zusammenarbeit mit den Asklepios-Fachkliniken München-Gauting durchgeführt. Dazu füllten Patienten standardisierte Instrumente zur Messung ihrer gesundheitsbezogenen Lebensqualität aus. So war es möglich, deutsche Daten in das Modell aufzunehmen, die auf einer Selbsteinschätzung der Patienten basieren. Der Ressourcenverbrauch zur Bestimmung der stadienspezifischen Kosten und die Bewertung beruhen auf einer deutschen Kostenstudie und aktuellen Preisen. Dabei wurden Krankenhausaufenthalte, ambulante ärztliche Leistungen, Medikamente, Rehabilitationen und Hilfsmittel sowie Produktionsausfälle durch Arbeits- und Erwerbsunfähigkeit berücksichtigt. Als Beispiel zur Anwendbarkeit des Modells diente ein Raucherentwöhnungsprogramm für Patienten mit leichter COPD. Dabei beeinflusste der Raucherstatus die Mortalität und die Wahrscheinlichkeit eines Krankheitsfortschritts. Die Implementierung dieses Modells erfolgte in den drei Softwarepaketen TreeAge, Excel und ARENA. Zur technischen Validierung wurden die Ergebnisse der drei Programme anschließend auf ihre Übereinstimmung hin überprüft. Außerdem wurden uni- und multivariate sowie probabilistische Sensitivitätsanalysen durchgeführt, um die Robustheit des Modellergebnisses zu untersuchen. Es zeigte sich, dass die gewählte Intervention im Vergleich zur Standardbehandlung dominant ist, also zu höheren Gesundheitseffekten bei gleichzeitig geringeren Kosten führt. Sensitivitätsanalysen wiesen darauf hin, dass die mit diesem Ergebnis verbundene Unsicherheit besonders auf fehlende Evidenz im Bereich der Kosten in leichten Krankheitsstadien basiert. Obwohl ein Großteil der COPD-Patienten in Deutschland ein leichtes oder moderates Stadium aufweist, fehlen gerade für diese frühen Schweregrade Studien zum Ressourcenverbrauch und den Krankheitskosten. Solche Daten sind jedoch dringend erforderlich, um die Wirtschaftlichkeit von Interventionen und die Belastung der Gesellschaft durch diese Erkrankung abschätzen zu können.Chronic obstructive pulmonary disease (COPD) is currently the forth leading cause of death worldwide. It has serious effects on patients and causes substantial societal costs every year. The aim of this work was to develop a decision-analytic model for COPD that applies current parameter values for Germany and that can be used for a health economic evaluation of interventions. A seven-stage Markov model was developed to conduct a cost-utility analysis from the societal perspective with a time horizon of 60 years. Patients entered the model at the age of 45 with mild COPD. In addition to stage-specific probabilities, utilities and costs were estimated and were discounted with 3%. To assess transition probabilities, an extensive literature search was conducted to identify the best available evidence for each parameter. As German data on disease progression are scarce, results of international studies had to be used for most parts. However, even internationally there are hardly any data available on utilities during acute exacerbations. Therefore, a study was planned to obtain these utilities. This study was conducted in cooperation with the Asklepios-Fachkliniken München-Gauting. Patients were asked about their health-related quality of life using standardized instruments. Thus, German data based on self-assessed health could be applied to the model. To calculate stage-specific costs, resource utilization from a German cost-study was used and valued with current price data. Costs for hospital stays, ambulatory physician visits, drug consumption, rehabilitation and devices as well as production losses caused by temporary inability to work or by permanent disability were considered. A smoking cessation program for patients with mild COPD was evaluated to demonstrate the applicability of the model. For this, an influence of smoking status was assumed on mortality and disease progression. This model was implemented in the three software packages TreeAge, Excel and ARENA. For a technical validation, the results of all three programmes were then tested for consistency. Furthermore, uni- and multivariate as well as probabilistic sensitivity analyses were conducted to assess the robustness of the model results. The intervention was the dominant strategy compared with usual care, as it resulted in increased health effects and reduced costs. Sensitivity analyses showed that uncertainty associated with the model result was mostly due to the lack of evidence for costs in early disease stages. Although the majority of COPD patients in Germany suffers from mild or moderate COPD, studies on resource use and costs are lacking especially for these early stages. However, these data are needed to assess the societal burden of disease and the cost-effectiveness of interventions

Multimorbidity and health-related quality of life in the older population: results from the German KORA-Age study

<p>Abstract</p> <p>Background</p> <p>Multimorbidity in the older population is well acknowledged to negatively affect health-related quality of life (HRQL). Several studies have examined the independent effects of single diseases; however, little research has focused on interaction between diseases. The purpose of this study was to assess the impact of six self-reported major conditions and their combinations on HRQL measured by the EQ-5D.</p> <p>Methods</p> <p>The EQ-5D was administered in the population-based KORA-Age study of 4,565 Germans aged 65 years or older. A generalised additive regression model was used to assess the effects of chronic conditions on HRQL and to account for the nonlinear associations with age and body mass index (BMI). Disease interactions were identified by a forward variable selection method.</p> <p>Results</p> <p>The conditions with the greatest negative impact on the EQ-5D index were the history of a stroke (regression coefficient -11.3, p < 0.0001) and chronic bronchitis (regression coefficient -8.1, p < 0.0001). Patients with both diabetes and coronary disorders showed more impaired HRQL than could be expected from their separate effects (coefficient of interaction term -8.1, p < 0.0001). A synergistic effect on HRQL was also found for the combination of coronary disorders and stroke. The effect of BMI on the mean EQ-5D index was inverse U-shaped with a maximum at around 24.8 kg/m².</p> <p>Conclusions</p> <p>There are important interactions between coronary problems, diabetes mellitus, and the history of a stroke that negatively affect HRQL in the older German population. Not only high but also low BMI is associated with impairments in health status.</p

Juvenile obesity and its association with utilisation and costs of pharmaceuticals - results from the KiGGS study

<p>Abstract</p> <p>Background</p> <p>According to a national reference, 15% of German children and adolescents are overweight (including obese) and 6.3% are obese. An earlier study analysed the impact of childhood overweight and obesity on different components of direct medical costs (physician, hospital and therapists). To complement the existing literature for Germany, this study aims to explore the association of body mass index (BMI) with utilisation of pharmaceuticals and related costs in German children and adolescents.</p> <p>Methods</p> <p>Based on data from 14, 836 respondents aged 3-17 years in the German Interview and Examination Survey for Children and Adolescents (KiGGS), drug intake and associated costs were estimated using a bottom-up approach. To investigate the association of BMI with utilisation and costs, univariate analyses and multivariate generalised mixed models were conducted.</p> <p>Results</p> <p>There was no significant difference between BMI groups regarding the probability of drug utilisation. However, the number of pharmaceuticals used was significantly higher (14%) for obese children than for normal weight children. Furthermore, there was a trend for more physician-prescribed medication in obese children and adolescents. Among children with pharmaceutical intake, estimated costs were 24% higher for obese children compared with the normal weight group.</p> <p>Conclusions</p> <p>This is the first study to estimate excess drug costs for obesity based on a representative cross-sectional sample of the child and adolescent population in Germany. The results suggest that obese children should be classified as a priority group for prevention. This study complements the existing literature and provides important information concerning the relevance of childhood obesity as a health problem.</p

Effects of general practitioner training and family support services on the care of home-dwelling dementia patients - Results of a controlled cluster-randomized study

<p>Abstract</p> <p>Background</p> <p>More than 90% of dementia patients are cared for by their general practitioners, who are decisively involved in the diagnosis, therapy and recommendation of support services. <it>Objective: </it>To test whether special training of general practitioners alters the care of dementia patients through their systematic recommendation of caregiver counseling and support groups.</p> <p>Method</p> <p>129 general practitioners enrolled 390 dementia patients and their informal caregivers in a prospective, three-arm cluster-randomized 2-year study. Arm A constituted usual care, in Arm B and C support groups and caregiver counseling (in Arm B one year after baseline, in Arm C at baseline) were recommended by the general practitioners. The general practitioners received arm-specific training. Diagnostic and therapeutic behavior of physicians was recorded at baseline. Informal caregivers were questioned in follow-up after 2 years about the utilization of support services.</p> <p>Results</p> <p>The diagnostic behavior of the general practitioners conforms to relevant guidelines. The procedure in newly-diagnosed patients does not differ from previously diagnosed patients with the exception of the rate of referral to a specialist. About one-third of the newly-diagnosed dementia patients are given an anti-dementia drug. The utilization of support groups and counseling increased five- and fourfold, respectively. Utilization of other support services remained low (< 10%), with the exception of home nursing and institutional short-term nursing.</p> <p>Conclusion</p> <p>Trained general practitioners usually act in conformity with guidelines with respect to diagnosing dementia, and partly in conformity with the guidelines with respect to recommended drug therapy. Recommendations of support services for informal caregivers by the general practitioner are successful. They result in a marked increase in the utilization rate for the recommended services compared to offers which are not recommended by the general practitioner.</p> <p>Trial registration</p> <p>ISRCTN68329593</p

Comparing Three Software Tools for Implementing Markov Models for Health Economic Evaluations

Background: Various software packages are commonly used for the implementation and calculation of decision-analytic models for health economic evaluations. However, comparison of these programs with regard to ease of implementing a model is lacking. Objectives: (i) to compare the assets and drawbacks of three commonly used software packages for Markov models with regard to ease of implementation; and (ii) to investigate how a technical model validation can be conducted by comparing the results of the three implementations. Methods: A Markov model on chronic obstructive pulmonary disease was implemented in TreeAge, Microsoft Excel and Arena with the same assumptions on model structure, transition probabilities and costs. A hypothetical smoking cessation programme for patients in stage 1 was evaluated against usual care. The packages were compared with respect to time and effort for implementation, run-time, features for the presentation of results, and flexibility. Agreement between the packages on average costs and life-years gained and on the incremental cost-effectiveness ratio was considered for technical validation in the form of expected values (between TreeAge and Excel only) and Monte Carlo simulations. Results: Ease of implementation was best in TreeAge, whereas Arena offered the highest flexibility. Deterministic results were in agreement between TreeAge and Excel, as were simulated values between all three packages. Conclusions: Excel offers an intuitive spreadsheet interface, but the acquisition of and the training in TreeAge or Arena is worthwhile for more complex models. Double implementation is a practicable validation technique that should be conducted to ensure correct model implementation.

The cost-effectiveness of tracking newborns with bilateral hearing impairment in Bavaria: a decision-analytic model

Abstract Background Although several countries, including Germany, have established newborn hearing screening programmes for early detection and treatment of newborns with hearing impairments, nationwide tracking systems for follow-up of newborns with positive test results until diagnosis of hearing impairment have often not been implemented. However, a recent study on universal newborn hearing screening in Bavaria showed that, in a high proportion of newborns, early diagnosis was only possible with the use of a tracking system. The aim of this study was, therefore, to assess the cost-effectiveness of tracking newborns with bilateral hearing impairment in Bavaria. Methods Data from a Bavarian pilot project on newborn hearing screening and Bavarian newborn hearing screening facilities were used to assess the cost-effectiveness of the inclusion of a tracking system within a newborn hearing screening programme. A model-based cost-effectiveness analysis was conducted. The time horizon of the model was limited to the newborn hearing screening programme. Costs of the initial hearing screening test and subsequent tests were included, as well as costs of diagnosis and costs of tracking. The outcome measure of the economic analysis was the cost per case of bilateral hearing impairment detected. In order to reflect uncertainty, deterministic and probabilistic sensitivity analyses were performed. Results The incremental cost-effectiveness ratio of tracking vs. no tracking was €1,697 per additional case of bilateral hearing impairment detected. Conclusions Compared with no tracking, tracking resulted in more cases of bilateral hearing impairment detected as well as higher costs. If society is willing to pay at least €1,697 per additional case of bilateral hearing impairment detected, tracking can be recommended.</p

Measurement of informal care time in a study of patients with dementia

Background: Previous assessments of informal care time have tended to consider only the amount of time spent with the patient by the primary informal caregiver; however, in many cases, more than one person is providing care for the patient. We assess total informal care time of people caring for patients with dementia, and estimate the bias that can arise if consideration is not made of the time spent by all participating informal caregivers. Method: We used an extended version of the questions on informal care time from the Resource Utilization in Dementia (RUD) instrument. Caregivers were asked to state the number of days and the number of hours on a typical day they had assisted the patient in activities of daily living (ADL), instrumental ADL (IADL), and supervision during the last four weeks. Multivariate regression analyses were conducted to identify factors that could account for the amount of informal care time. Results: 357 informal caregivers took part. Values were missing from only 4.5% of all interviews. On average, the primary informal caregiver cared for the patient 1.5, 2.1 and 1.9 hours per day in ADL, IADL and supervision respectively. Fifty-seven percent of all patients had more than one informal caregiver. Total informal care time was underestimated by about 14% if the time of caregivers other than the primary caregiver was not taken into account. The informal care time was significantly higher if the caregiver was the patient's partner and the patient's health status was lower. Conclusion: Our results show that most previous studies probably underestimated costs of informal care because the time of informal caregivers other than the primary caregiver was not considered