Table 2.
Main study characteristics of cost-effectiveness studies of total knee arthroplasty (n = 33).
| Study characteristic | Number of studies | Percentage contribution to total (% to 1 decimal point) |
|---|---|---|
| Country of study | ||
| United States | 12 | 36.4 |
| United Kingdom | 9 | 27.3 |
| Canada | 3 | 9.1 |
| Other (Europe) | 9 | 27.3 |
| Study design | ||
| Randomised controlled trial | 5 | 15.2 |
| Prospective cohort | 3 | 9.1 |
| Markov | 17 | 51.5 |
| Decision Tree | 4 | 12.1 |
| Not stated | 4 | 12.1 |
| Data mining (health outcomes and costs) explained | ||
| Yes | 33 | 100 |
| No | 0 | 0 |
| Level of evidencea | ||
| I | 12 | 36.4 |
| II | 9 | 27.3 |
| III | 5 | 15.2 |
| IV | 7 | 21.2 |
| Perspective | ||
| Healthcare payer | 18 | 54.5 |
| Societal | 7 | 21.2 |
| Both | 4 | 12.1 |
| Not stated | 4 | 12.1 |
| Time Horizon | ||
| ≤10 years | 9 | 27.3 |
| >10 years | 7 | 21.2 |
| Lifetime | 17 | 51.5 |
| Not stated | 1 | 3.0 |
| Sufficient Time Horizon and Discounting (both costs and health outcomes) present | ||
| Yes | 26 | 78.8 |
| No | 7 | 21.2 |
| Sensitivity Analysis | ||
| Deterministic only | 5 | 15.2 |
| Probabilistic only | 4 | 12.1 |
| Both | 15 | 45.5 |
| Not stated | 8 | 24.2 |
| Unspecified | 1 | 3.0 |
| Statement of funding | ||
| Yes | 19 | 57.6 |
| No | 14 | 42.4 |
| Discussion of potential bias present | ||
| Yes | 8 | 24.2 |
| No | 25 | 75.8 |
“Other” countries include: Belgium, Denmark, Germany, Italy, Netherlands, Norway, Romania, and Spain.
a
Based on recommendations by Wright et al. (2003) for judging the level of evidence for a primary research question [64].