Considerations For Conducting An Economic Evaluation Of Complex System Intervention - Medication Review
T. Szymanski1, 2, J. Reed1, 2, L. Holger Ehlers3, 4, D. Bell1, 2
1Imperial College London, 2NIHR CLAHRC Northwest London, 3Aalborg University, 4Danish
Center for Healthcare Improvements
Currently, there is not much agreed methodology on economic evaluation in quality improvement. Many cost-effectiveness studies fail to include complexity in their evaluations. We aim to consider how the role of complexity can influence the results of cost-effectiveness analysis. We apply 6 criteria published by Institute of Health Economics (IHE)1 in order to see what is the difference when evaluating simple and complex interventions. To illustrate this we use a medication review in acute care as a case study.
We conducted a literature review to identify articles describing the complexity of medication review. A database search of MEDLINE and Google Scholar was conducted, followed by snowballing of relevant results. Framework analysis using the IHE criteria was used to classify the complexity of hospital medication review.
Complex system interventions like medication review are difficult to evaluate given the scope and number of factors to consider. When evaluating these interventions, the classic health economic approach may not fully capture the complexity of the intervention. Therefore it is essential to account for context and complexity when conducting a cost-effectiveness analysis in this setting.
Four systematic literature reviews3-6, three cost-effectiveness studies7-9 and one national guidance10 were included in the review. The differences in evaluation of simple and complex intervention (medication review) are presented in the table below.
- Valuing outcomes:
Single outcome e.g. Quality Adjusted Life Years
Health service perspective
Gold standard for evaluating effectiveness of an intervention are systematic reviews and randomized control trials. They rarely account for context in which the intervention is delivered.
- Resource use and costs:
Cost and resources quantifiable
Long-term outcomes e.g. mortality
- Valuing outcomes
Multiple outcomes (apart from patient health outcomes, medication review can provide broader health system outcomes e.g. staff engagement, accessibility, patient and public engagement/involvement
Medication review is already in place in the UK. However, its consistency and quality could be improved. Therefore, the comparator can be a medication review done irregularly or low quality medication review
Broader perspective that includes benefits and costs for every stakeholder
Context is a critical determining factor on the success of an intervention. There are many variables likely to influence effectiveness of medication review:
a) Behavioural factors (experience of the healthcare professional; engagement of the patient; communication between different health care professionals)
b) Systemic factors (resources in place; time availability; interaction between different parts of the healthcare system)
- Resource use and costs:
Main resource (time to complete medication review) is case sensitive. It might be dependent on the number of drugs prescribed, age and condition of the patient
Results from studies might not reflect long-term outcomes. The final outcomes, can be estimated based on surrogate outcomes
1. Economic evaluation of complex health system interventions: a discussion paper. 2014;(July):38.
2. Christensen, M. & Lundh, A., 2016. Medication review in hospitalised patients to reduce morbidity and mortality. The Cochrane database of systematic reviews, 2(2), p.CD008986. Available at: http://www.ncbi.nlm.nih.gov/pubmed/23450593.
3. Christensen, M. & Lundh, A., 2013. Medication review in hospitalised patients to reduce morbidity and mortality. The Cochrane database of systematic reviews, 2(2), p.CD008986. Available at: http://www.ncbi.nlm.nih.gov/pubmed/23450593.
4. Graabaek, T. & Kjeldsen, L.J., 2013. Medication Reviews by Clinical Pharmacists at Hospitals Lead to Improved Patient Outcomes: A Systematic Review. Basic & Clinical Pharmacology & Toxicology, 112(6), pp.359–373. Available at: http://doi.wiley.com/10.1111/bcpt.12062.
5. Hohl, C.M. et al., 2015. The effect of early in-hospital medication review on health outcomes: a systematic review. British Journal of Clinical Pharmacology, p.n/a–n/a. Available at: http://doi.wiley.com/10.1111/bcp.12585.
6. Gallagher, J. et al., 2016. Structured Pharmacist Review of Medication in Older Hospitalised Patients: A Cost-Effectiveness Analysis. Drugs & Aging, pp.1–10. Available at: http://link.springer.com/10.1007/s40266-016-0348-3.
7. Ghatnekar, O. et al., 2013. Health economic evaluation of the Lund Integrated Medicines Management Model ( LIMM ) in elderly patients admitted to hospital, pp.1–10.
8. Wallerstedt, S.M., Bladh, L. & Ramsberg, J., 2012. A cost-effectiveness analysis of an in-hospital clinical pharmacist service. BMJ Open, 2(1), pp.e000329–e000329. Available at: http://bmjopen.bmj.com/content/2/1/e000329.
9. NICE, 2015. Medicines optimisation : the safe and effective use of medicines to enable the best possible outcomes. National Institute for Health and Care Excellence guidance, pp.1–47. Available at: https://www.nice.org.uk/guidance/ng5