ORAL ABSTRACTS: DIAGNOSIS
Method(s): A discrete-event simulation mathematical model was developed of the depression care pathway experienced by people diagnosed with type-2 diabetes in England. Model parameters were based on systematic reviews of the literature. The model was used to assess the costs and health outcomes associated with the potential service changes from an NHS perspective, wider social benefits were also explored. The lifetime outcomes considered were time spent with depression, diabetes-related complications, quality adjusted life years (QALYs), mortality, and healthcare system costs. The changes were considered both separately and in combination, resulting in three potential service changes.
Result(s): All three changes were associated with reductions in both the time spent with depression and the number of diabetes-related complications experienced. In addition, each of the three policies was associated with an improvement in quality of life and an increase in both life years and depression-free years compared with current practice, but also with an increase in health care costs. Collaborative care dominated improved opportunistic screening, being both cheaper and more effective. The incremental cost-effectiveness ratio (ICER) for collaborative care compared with current care pathways was £10,798 per QALY. Compared to collaborative care, the combined policy of both collaborative care and opportunistic screening had an ICER of £68,017 per QALY.
Conclusion(s): Service changes to improve the diagnosis of, and treatment of, depression in patients with diabetes may lead to reductions in diabetes related complications and depression, which in turn increases life expectancy and improves health-related quality of life. However, all three service changes lead to an increase in health care costs. Of the changes considered, implementing collaborative care was cost-effective based on current national guidance in England.
Method(s): A decision analytic model was developed to estimate healthcare costs and QALYs for a clinical practice strategy and a diagnostic strategy in patients with hepatocellular carcinoma. The clinical practice strategy reflects current clinical decision making. The diagnostic strategy uses a non-invasive diagnostic technology that determines several central aspects of liver function based on magnetic resonance imaging, and processes this information into a visualization tool to support clinical decision making. The decision analytic model incorporates how knowledge of liver function status may impact treatment decisions and the prognosis of implemented treatments due to increased surgical precision. Expert opinion was used to estimate the impact on treatment decisions, the Swedish registry of tumors in the liver and bile ducts (Sweliv), together with published literature was used to inform long-term prognosis of implemented treatments. To reflect the substantial uncertainty associated with the use of the new diagnostic strategy, extensive sensitivity scenarios were investigated. Costs and QALYs were estimated from a Swedish healthcare perspective.
Result(s): In the most plausible scenarios, QALYs gained with a diagnostic strategy varied between 0.07 and 0.26, yielding cost per QALY estimates of €7500 to €3500 compared with a clinical practice strategy. Treatment decisions (a larger proportion of patients undergoing resection) and improved long-term prognosis (due to optimal resection) contributed equally to the gain in QALYs. Incremental costs associated with the diagnostic strategy were primarily driven by resection costs and additional costs associated with improved survival, and not the actual cost of the diagnostic procedure.
Conclusion(s): This early evaluation indicates that a diagnostic visualization tool in patients with hepatocellular carcinoma will improve health outcomes at a cost below generally acceptable thresholds of cost-effectiveness. Furthermore, the evaluation provides a structured framework to prioritize further research, and also to assess the value of the diagnostic technology in other disease areas than hepatocellular carcinoma.
Current diagnostic algorithms for investigating alcoholic liver disease (ALD) are based in secondary care which is associated with considerable costs and late diagnosis. We investigated the cost-effectiveness from an NHS England perspective of a community-based innovative diagnostic pathway (IDP) which stratifies patients at risk of ALD.
An economic evaluation was conducted to compare IDP, a pathway which identifies patients at risk of ALD in primary care and utilises transient elastography and a community hepatologist review to stratify patients, with standard care (SC), a referral to secondary care based on abnormal liver function tests. Brief alcohol intervention was assumed to be implemented in both arms.
Markov modelling of the natural history of ALD was combined with results of a prospective cross-sectional feasibility study (data on IDP and SC diagnostic accuracies). The following states were included in the model: no/mild liver disease (+/-), significant liver disease (+/-), compensated cirrhosis (+/-), split dependent on whether early disease is detected and treated (+) or not (-), decompensated cirrhosis, hepatocellular carcinoma, liver transplant and death. Starting age was 43, with 1-year cycle length and lifetime horizon, costs and utilities were discounted at 3.5%. Transition probability, utility and resource use data were taken from up-to-date UK sources. Due to poor data available for early disease progression and management, an expert panel of hepatologists was consulted to generate indicative estimates of probabilities and resource use.
An incremental cost-effectiveness ratio (ICER) was estimated, with extended one-way sensitivity analysis (OSA) to assess robustness of the results. Probabilistic sensitivity analysis (PSA) was performed, plotting an ICER-scatter-plane and a cost-effectiveness acceptability curve.
The analysis showed an ICER of £6,537 per extra quality adjusted life year (QALY), with QALY gain (0.45) and incremental cost (£2,973). OSA demonstrated ICER was robust and most sensitive to estimates on the effect of treatment on reducing the rate of fibrosis progression. PSA showed an ICER of £7,468/QALY (2.5%- 97.5% percentiles: 988-51,257), with QALY gain, 0.41 (0.00-0.88), and incremental cost, £3,137 (1,306-5,005), and demonstrated an 87% probability of cost-effectiveness at the UK willingness-to-pay threshold of £20,000/QALY.
IDP was cost-effective compared with SC, even in the presence of significant uncertainty around estimates. This suggests that IDP is likely to represent good value for money if implemented.
Method(s): We developed a decision tree model to simulate one year patient courses with each of the strategies. Sensitivity and specificity of clinical diagnosis (56% and 68%) and of NT-proBNP test (90% and 65%) were based on published literature. The probabilities of referral to hospital given a test outcome were based on a survey of Norwegian GPs (n=103). The costs were based on various Norwegian fee schedules. Sensitivity analyses were conducted to examine the uncertainty of the results.
Result(s): The one-year societal costs were NOK4,897, NOK 4,544 and NOK5,467 for clinical diagnosis, POC-test and hospital test, respectively (€1.00≈NOK9.00). Even though POC testing entails higher laboratory costs than the other test modalities, the total primary care costs are lower with such testing because of fewer re-consultations with the GP and less use of spirometry. POC testing also entails lower hospital costs because of fewer false positive heart failure tests. Finally, patients’ travel costs are lower with POC-test because of fewer re-consultations and fewer unnecessary referrals to hospital. While 38% of patients had a delayed correct diagnosis with clinical diagnosis, the proportions were 22% with POC-test and hospital-test. The model was most sensitive to the cost of being referred to a specialist physician and to the specificity to the three tests. The results were only marginally affected by changes in input variables.
Conclusion(s): POC-testing results in earlier diagnosis and lower costs than the other diagnostic modalities.
Method(s): Data from a large Dutch cohort study (n=19484; mean follow up 12.3 years) was used to investigate differences in composite endpoints of four widely used CVD risk prediction models: the Adult Treatment Panel III (ATP), Framingham Global (FRS), Pooled Cohort Equations (PCE) and SCORE-low (SCORE) models. Across these four prediction models, we calculated the 10-year individual CVD risks and the corresponding health loss based on the CVD event types included in the composite endpoint. Subsequently, each prediction model was used to estimate the expected CVD burden in the 25% individuals with highest predicted risks, expressed as Quality-Adjusted Life Years (QALYs) lost.
Result(s): The observed constitution of the composite endpoints varied widely across the four models. For example, the percentage non-fatal MI events was 81%, 19%, 37%, and 0% according to ATP, FRS, PCE, and SCORE respectively, and for fatal MI this was 19%, 5%, 9%, and 57%, respectively. FRS predicted the highest CVD risks and the composite endpoint used in SCORE had the highest health burden. The predicted CVD burden in the 25% individuals with highest predicted risk was 0.19, 0.72, 0.36, and 0.23 QALYs lost per individual when using ATP, FRS, PCE and SCORE, respectively.
Conclusion(s): The investigated CVD risk prediction models showed huge variation in definition and constitution of the composite endpoints. This directly resulted in large differences in estimated CVD burden. When interpreting the estimated CVD burden derived with a risk prediction model, it is therefore crucial to consider which CVD event types are included, and which are excluded, in that prediction model.
Method(s): We adapted an individual-based microsimulation model to reflect HPV and cervical cancer burden in Norway, including HPV infection status and persistence in progression to precancer and cancer. We projected the health and economic consequences associated with ten candidate strategies to triage women with minor cervical cytological lesions who were also high-risk HPV-positive. Candidate strategies varied by: 1) the triage test(s): HPV testing with cytology (i.e., current Norwegian guidelines), HPV testing alone with or without genotyping for HPV-16 and-18 (the two most carcinogenic types), and immediate colposcopy, and 2) the length of time between index and triage testing (i.e., ranging 6-18 months). Model outcomes included lifetime risk of cervical cancer, quality-adjusted life-years (QALYs), lifetime societal costs, and resource use (e.g., number of colposcopy referrals) associated with each strategy. We estimated the incremental cost-effectiveness ratio (ICER) to identify cost-efficient strategies.
Result(s): The candidate strategies were projected to reduce the lifetime risk of cervical cancer by 84.2% to 85.9%, and were more effective and less costly than current Norwegian guidelines. Given current willingness-to-pay recommendations in Norway of $100,000 per QALY gained, the preferred strategy involved immediate colposcopy for all high-risk HPV-positive women ($80,310 per QALY gained). This strategy was associated with a 21% increase in colposcopy referrals and a 15% increase in precancer treatments compared with current levels. Strategies involving immediate colposcopy only for women with HPV-16 or -18, and repeat HPV testing for women with non-HPV-16/-18 high-risk genotypes (at 18 or 12 months), had lower, more attractive ICERs, and required moderate increases in colposcopy and treatment referrals compared with current guidelines.
Conclusion(s): New applications of HPV testing in screening triage are likely to increase health benefit at lower costs than current Norwegian guidelines. However, the minor improvements in health benefits associated with more effective strategies require a tradeoff of increased colposcopy referrals and precancer treatments.