Stats - Economic Evaluation, Delphi and STAR*D Flashcards
What are the 4 basic types of economic evaluation we need to know?
cost-effectiveness analysis (CEA)
cost-benefit analysis (CBA)
cost-utility analysis (CUA)
cost-minimisation analysis (CMA)
E-BUM
What is cost-effectiveness analysis?
CEA compares a number of interventions by relating costs to a single clinical measure of effectiveness (e.g. symptom reduction, improvement in activities of daily living).
cost-effectiveness ratio = total cost / units of effectiveness
For example consider this study on anorexia which compared the costs of three approaches to treatment (inpatient, specialist outpatient, and general outpatient) per improvement on the MorganRussell Average Outcome Scale (Byford, 2007).
Other examples:
£’s spent per lives saved
£’s spent per each depression free day
CEA is generally done when CBA cannot be performed due to the inability to monetise benefits.
Combining both costs and effects, the findings of a CEA are usually reported as an incremental cost-effectiveness ratio (ICER).
ICER intervention A versus intervention B = (costs A - costs B) / (effects A - effects B)
A treatment that is found to be BOTH more costly AND less effective is said to be ‘dominated’ by the other treatment.
The advantage of expressing health outcomes in natural units is that these are often observable, relatively easy to measure and, often, meaningful to clinicians. The disadvantage, however, is that they limit the scope of comparisons. For example, cost-effectiveness analyses using outcomes such as depression-free days achieved only allow comparisons with other interventions that can be expressed using exactly the same metric. Survival-related outcomes such as life years gained allow comparisons over a broader range of conditions, but they disregard morbidity and quality of life.
What is cost-benefit analysis?
CBA is a technique in which all the costs and benefits of an intervention are measured in terms of money. A CBA is used to establish which of the alternatives has the greatest net benefit.
CBA requires that all the consequences of an intervention, such as life-years saved, treatment side-effects, symptom relief, disability, pain and discomfort, are allocated a monetary value.
CBA is relatively rarely used in mental health service evaluation mainly due to the difficulty in converting benefits from mental health programmes into monetary values.
What is cost-utility analysis?
CUA is a special form of CEA in which health benefits / outcomes are measured in broader, more generic ways enabling comparisons between treatments for different diseases and conditions.
Multidimensional health outcomes are measured by a single preference- or utility-based index such as the QALY.
Quality-Adjusted-Life-Years (QALYs). QALYs are a composite measure of gains in life expectancy and health-related quality of life. One QALY is equal to 1 year of life in perfect health. QALYs are calculated by estimating the years of life remaining for a patient following a particular treatment or intervention and weighting each year with a quality-of-life score (on a 0 to 1 scale). The quality of life score can be negative in situations where the outcome is considered to be worse than death (death = 0 on the scale).
CUA offers something that CEA cannot, which is to compare across treatments for different conditions. In principle, it is possible to compare treatments for, say, cancer with, say, schizophrenia to determine which is the most efficient at producing health gain in the form of QALYs.
Findings of CUA are often reported as an incremental cost-utility ratio (ICUR).
ICUR intervention A versus intervention B = (costs A - costs B) / (QALYs gained by A - QALYs gained by B)
Byford (2007) Economic evaluation of a randomised controlled trial for anorexia nervosa in adolescents. The British Journal of Psychiatry Oct, 191 (5) 436-440.
What is cost-minimisation analysis?
An economic evaluation in which consequences of competing interventions are the same and in which only inputs, that is, costs are taken into consideration. The aim is to decide the least costly way of achieving the same outcome.
What are the 3 types of cost we can measure using economic evaluation studies?
1) Direct - those associated directly with the healthcare intervention (e.g. staff time, medical supplies, cost of travel for the patient, childcare costs for the patient, costs falling on other social sectors such as domestic help from social services)
2) Indirect - those incurred by the reduced productivity of the patient (e.g. time of work, reduced work productivity, time spent caring for the patient by relatives)
3) Intangible - those that are difficult to measure (e.g. pain or suffering on the part of the patient)
What is the Delphi Method?
The Delphi technique was developed in the 1950s and is a widely used and accepted method for achieving convergence of opinion concerning real-world knowledge solicited from experts within certain topic areas.
How is the Delphi process carried out?
The Delphi process traditionally begins (round one) with an open-ended questionnaire. After receiving subjects responses, investigators need to convert the collected information into a well-structured questionnaire. This questionnaire is used as the survey instrument for the second round of data collection.
In the second round, each Delphi participant receives a second questionnaire and is asked to review the items summarized by the investigators based on the information provided in the first round. Accordingly,
Delphi panellists may be required to rate or rank-order items to establish preliminary priorities among items. As a result of round two, areas of disagreement and agreement are identified
In the third round, each Delphi panellist receives a questionnaire that includes the items and ratings summarized by the investigator in the previous round and are asked to revise his/her judgements or to specify the reasons for remaining outside the consensus This round gives Delphi panellists an opportunity to make further clarifications of both the information and their judgements of the relative importance of the items. However, compared to the previous round, only a slight increase in the degree of consensus can be expected.
What is the most important step in the process of the Delphi method?
Choosing the appropriate subjects is the most important step in the entire process because it directly relates to the quality of the results generated, despite this, there is no exact criterion currently listed in the literature concerning the selection of Delphi participants. Delphi subjects should be highly trained and competent within the specialized area of knowledge related to the target issue.
What are 4 possible issues with the Delphi method?
1) a Delphi study can be time-consuming as several days or weeks may pass between rounds
2) the potential exists for low response rates and striving to maintain robust feedback can be a challenge
3) the Delphi technique can potentially enable investigators to mould opinions
4) the expertise of Delphi panelists could be unevenly distributed
What does the STAR*D trial stand for?
What is it?
Sequenced Treatment Alternatives to Relieve Depression
It was a pragmatic (real world) trial conducted in 2006 in the USA which aimed to assess the effectiveness of treatments in patients diagnosed with major depressive disorder.
A total of 4,041 patients were enrolled in the first level of treatment, making STAR*D the largest prospective clinical trial of depression ever conducted.
How many treatment levels were there in STAR*D? What did the levels mean?
4
Patients were started on a treatment called level 1. If they failed to respond to this they were given another treatment called level 2. This continued up to level 4.
What was Level 1 in the STAR*D trial?
Level 1 - This consisted of citalopram (given for 14 weeks)
What was Level 2 in the STAR*D trial?
Level 2 - This consisted of either swapping to sertraline, bupropion, or venlafaxine, or augmenting with bupropion, or buspirone. Cognitive psychotherapy was also included as a switch or add on at this level.
What was Level 3 in the STAR*D trial?
Level 3 - This consisted of swapping to mirtazapine or nortriptyline or adding on lithium or triiodothyronine (T3).
